Regional left ventricular myocardial contraction abnormalities and asynchrony in patients with hypertrophic cardiomyopathy evaluated by magnetic resonance spatial modulation of magnetization myocardial tagging

International Nuclear Information System (INIS)

Mishiro, Yuichiro; Oki, Takashi; Iuchi, Arata

1999-01-01

Global left ventricular (LV) pump function is generally preserved in patients with hypertrophic cardiomyopathy (HCM). However, it is unknown whether regional myocardial contractility is impaired, especially in nonhypertrophied regions. The purpose of this study was to evaluate regional LV myocardial contraction in patients with HCM using magnetic resonance (MR) spatial modulation of magnetization (SPAMM) myocardial tagging. The study group comprised 20 patients with asymmetric septal hypertrophy (HCM group) and 16 age-matched normal patients (control group), and data were collected using transthoracic M-mode and 2-dimensional echocardiography, and MR SPAMM myocardial tagging. The systolic strain ratio, maximum systolic strain velocity, and time from end-diastole to maximum systolic strain (ΔT) in the anterior, ventricular septal, inferior and lateral regions for 2 LV short-axis sections at the levels of the chordae tendineae and papillary muscles were measured at 50-ms intervals by MR myocardial tagging. The end-diastolic anterior and ventricular septal wall thicknesses and LV mass index were significantly different between the HCM and control groups. The systolic strain ratio for all 4 walls, particularly the anterior and ventricular septal regions, was significantly lower in the HCM group. In the HCM group, the maximum systolic strain velocity was significantly lower and ΔT was significantly shorter for all 4 walls, particularly the anterior and ventricular septal regions. The standard deviation for the ΔT, calculated from the ΔT for the 8 regions of the 2 LV short-axis sections, was significantly greater in the HCM group. In conclusion, regional LV myocardial contraction is impaired in both hypertrophied and nonhypertrophied regions, and systolic LV wall asynchrony occurs in patients with HCM. (author)

Contribution of contractile state of the non-infarcted area to global ventricular performance after acute myocardial infarction

International Nuclear Information System (INIS)

Nishimura, Tsunehiko; Yasuda, Tsunehiro; Gold, H.K.; Leinbach, R.C.; Boucher, C.A.; McKusick, K.A.; Strauss, H.W.

1986-01-01

To evaluate the regional contractile state of the non-infarcted zone and to determine the contribution of this area to left ventricular (LV) performance, 112 patients (42 anterior and 70 inferior infarction) with their first acute myocardial infarction were investigated by radionuclide ventriculography at admission and 10 days after admission. Wall motion at the non-infarcted area was defined as hyperkinetic, normal, or hypokinetic, if radial chord shortening had above normal, normal, or below normal values, respectively, by quantitative wall motion analysis. Hyperkinetic, normal, and hypokinetic wall motion of the non-infarcted area were observed in three (7 %), 12 (29 %), and 27 (64 %) patients in anterior infarction and 14 (20 %), 28 (40 %), and 28 (40 %) in inferior infarction, respectively. In the patients with hypokinetic wall motion at the non-infarcted area, the infarct involved more than 30 % of the left ventricle manifesting akinetic contractile segment (ACS), radial chord shortening in the infarcted area was severely depressed, and the incidence of multi-vessel involvement was higher compared with those with hyperkinetic or normal wall motion. In serial measurements, radial chord shortening in the infarcted and non-infarcted area, percent ACS, left ventricular ejection fraction, and left ventricular end-diastolic volume index did not change significantly from acute to follow-up study in any group. In conclusion, our data indicated that the non-infarcted area following acute infarction had various contractile states and these conditions were determined primarily by the severity and extent of infarct and underlying coronary artery disease. Furthermore, the contractile state of the non-infarcted area has a supplemental role in determination of LV function following acute infarction. (author)

Cardiac-Specific Overexpression of Catalase Attenuates Lipopolysaccharide-Induced Myocardial Contractile Dysfunction: Role of Autophagy

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Turdi, Subat; Han, Xuefeng; Huff, Anna F.; Roe, Nathan D.; Hu, Nan; Gao, Feng; Ren, Jun

2012-01-01

Lipopolysaccharide (LPS) from Gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complication in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged with LPS (6 mg/kg) and cardiac function was evaluated. Levels of oxidative stress, autophagy, apoptosis and protein damage were examined using fluorescence microscopy, Western blot, TUNEL assay, caspase-3 activity and carbonyl formation. Kaplan-Meier curve was constructed for survival following LPS treatment. Our results revealed a lower mortality in catalase mice compared with FVB mice following LPS challenge. LPS injection led to depressed cardiac contractile capacity as evidenced by echocardiography and cardiomyocyte contractile function, the effect of which was ablated by catalase overexpression. LPS treatment induced elevated TNF-α level, autophagy, apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), production of ROS and O2−, and protein carbonyl formation, the effects of which were significantly attenuated by catalase overexpression. Electron microscopy revealed focal myocardial damage characterized by mitochondrial injury following LPS treatment, which was less severe in catalase mice. Interestingly, LPS-induced cardiomyocyte contractile dysfunction was prevented by antioxidant NAC and the autophagy inhibitor 3-methyladenine. Taken together, our data revealed that catalase protects against LPS-induced cardiac dysfunction and mortality, which may be associated with inhibition of oxidative stress and autophagy. PMID:22902401

The cardiomyopathy in Friedreich's ataxia: isotopic ventriculography and myocardial imaging with thallium-201

International Nuclear Information System (INIS)

Therriault, L.; Lamoureux, G.; Cote, M.; Plourde, G.; Lemieux, B.

1984-01-01

Myocardial scanning after the intravenous administration of Thallium 201 was used to evaluate regional myocardial perfusion in 14 patients with Friedreich's ataxia. Isotopic ventriculography was also used to assess left ventricular contractility. Myocardial images in patients with Friedreich's ataxia were found to be precociously abnormal irrespective of the degree of neurological impairment or of the severity of myocardial hypertrophy

Cardiac-specific overexpression of catalase attenuates lipopolysaccharide-induced myocardial contractile dysfunction: role of autophagy.

Science.gov (United States)

Turdi, Subat; Han, Xuefeng; Huff, Anna F; Roe, Nathan D; Hu, Nan; Gao, Feng; Ren, Jun

2012-09-15

Lipopolysaccharide (LPS) from gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complications in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged with LPS (6 mg/kg) and cardiac function was evaluated. Levels of oxidative stress, autophagy, apoptosis, and protein damage were examined using fluorescence microscopy, Western blot, TUNEL assay, caspase-3 activity, and carbonyl formation. A Kaplan-Meier curve was constructed for survival after LPS treatment. Our results revealed a lower mortality in catalase mice compared with FVB mice after LPS challenge. LPS injection led to depressed cardiac contractile capacity as evidenced by echocardiography and cardiomyocyte contractile function, the effect of which was ablated by catalase overexpression. LPS treatment induced elevated TNF-α level, autophagy, apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), production of ROS and O(2)(-), and protein carbonyl formation, the effects of which were significantly attenuated by catalase overexpression. Electron microscopy revealed focal myocardial damage characterized by mitochondrial injury after LPS treatment, which was less severe in catalase mice. Interestingly, LPS-induced cardiomyocyte contractile dysfunction was prevented by the antioxidant N-acetylcysteine and the autophagy inhibitor 3-methyladenine. Taken together, our data revealed that catalase protects against LPS-induced cardiac dysfunction and mortality, which may be associated with inhibition of oxidative stress and autophagy. Copyright © 2012 Elsevier Inc. All rights reserved.

Ventricular and myocardial scintiscanning: Methodical fundamentals

International Nuclear Information System (INIS)

Standke, R.; Hoer, G.; Maul, F.D.

1984-01-01

Nuclear cardiology is concerned with non invasive procedures to quantitate global and regional left ventricular function (Radionuclide ventriculography), also the imaging of vitally perfused myocardium (Myocardial scintigraphy) is achieved. A gammacamera and a minicomputer are necessary. Radionuclide ventriculography enables the analysis of global and regional time dependent left ventricular volume curves and hence the evaluation of contraction and contractility of the heart muscle. The basis is a sequence of scans covering an average heartcycle. This sequence may be produced either by first pass or equilibrium technique. Myocardial scintigraphy at rest images vital myocardium, scans immediately after exercise represent the interference of myocardial perfusion and muscle mass. The regional difference (Redistribution) between normalized exercise- and rest scans provide quantitative parameters to detect impairment of exercise-induced myocardial perfusion anomalies. The procedures of sectorial analysis of left ventricular function and myocardial perfusion are presented. (orig.) [de

3D cardiac wall thickening assessment for acute myocardial infarction

Science.gov (United States)

Khalid, A.; Chan, B. T.; Lim, E.; Liew, Y. M.

2017-06-01

Acute myocardial infarction (AMI) is the most severe form of coronary artery disease leading to localized myocardial injury and therefore irregularities in the cardiac wall contractility. Studies have found very limited differences in global indices (such as ejection fraction, myocardial mass and volume) between healthy subjects and AMI patients, and therefore suggested regional assessment. Regional index, specifically cardiac wall thickness (WT) and thickening is closely related to cardiac function and could reveal regional abnormality due to AMI. In this study, we developed a 3D wall thickening assessment method to identify regional wall contractility dysfunction due to localized myocardial injury from infarction. Wall thickness and thickening were assessed from 3D personalized cardiac models reconstructed from cine MRI images by fitting inscribed sphere between endocardial and epicardial wall. The thickening analysis was performed in 5 patients and 3 healthy subjects and the results were compared against the gold standard 2D late-gadolinium-enhanced (LGE) images for infarct localization. The notable finding of this study is the highly accurate estimation and visual representation of the infarct size and location in 3D. This study provides clinicians with an intuitive way to visually and qualitatively assess regional cardiac wall dysfunction due to infarction in AMI patients.

Three-dimensional regional strain analysis in porcine myocardial infarction: a 3T magnetic resonance tagging study

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Soleimanifard Sahar

2012-12-01

Full Text Available Abstract Background Previous studies of mechanical strain anomalies in myocardial infarction (MI have been largely limited to analysis of one-dimensional (1D and two-dimensional (2D strain parameters. Advances in cardiovascular magnetic resonance (CMR methods now permit a complete three-dimensional (3D interrogation of myocardial regional strain. The aim of this study was to investigate the incremental value of CMR-based 3D strain and to test the hypothesis that 3D strain is superior to 1D or 2D strain analysis in the assessment of viability using a porcine model of infarction. Methods Infarction was induced surgically in 20 farm pigs. Cine, late gadolinium enhancement, and CMR tagging images were acquired at 11 days before (baseline, and 11 days (early and 1 month (late after induction of infarct. Harmonic phase analysis was performed to measure circumferential, longitudinal, and radial strains in myocardial segments, which were defined based on the transmurality of delayed enhancement. Univariate, bivariate, and multivariate logistic regression models of strain parameters were created and analyzed to compare the overall diagnostic accuracy of 3D strain analysis with 1D and 2D analyses in identifying the infarct and its adjacent regions from healthy myocardium. Results 3D strain differed significantly in infarct, adjacent, and remote segments (p  Conclusions Cumulative 3D strain information accurately identifies infarcts and their neighboring regions from healthy myocardium. The 3D interrogation of myocardial contractility provides incremental diagnostic accuracy in delineating the dysfunctional and nonviable myocardium in comparison with 1D or 2D quantification of strain. The infarct neighboring regions are the major beneficiaries of the 3D assessment of regional strain.

Myocardial Contractile Dysfunction is Present Without Histopathology in a Mouse Model of Limb-Girdle Muscular Dystrophy-2F and is Prevented after Claudin-5 Virotherapy

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Nima Milani-Nejad

2016-12-01

Full Text Available AbstractMutations in several members of the dystrophin glycoprotein complex lead to skeletal and cardiomyopathies. Cardiac care for these muscular dystrophies consists of management of symptoms with standard heart medications after detection of reduced whole heart function. Recent evidence from both Duchenne muscular dystrophy patients and animal models suggests that myocardial dysfunction is present before myocardial damage or deficiencies in whole heart function, and that treatment prior to heart failure symptoms may be beneficial. To determine whether this same early myocardial dysfunction is present in other muscular dystrophy cardiomyopathies, we conducted a physiological assessment of cardiac function at the tissue level in the δ-sarcoglycan null mouse model (Sgcd-/- of Limb-girdle muscular dystrophy type 2F. Baseline cardiac contractile force measurements using ex vivo intact linear muscle preparations, were severely depressed in these mice without the presence of histopathology. Virotherapy with claudin-5 prevents the onset of cardiomyopathy in another muscular dystrophy model. After virotherapy with claudin-5, the cardiac contractile force deficits in Sgcd-/- mice are no longer significant. These studies suggest that screening Limb-girdle muscular dystrophy patients using methods that detect earlier functional changes may provide a longer therapeutic window for cardiac care.

The Myocardial Performance Index During Low Dose Dobutamine Echocardiography in Normals and Patients With a Recent Myocardial Infarction

DEFF Research Database (Denmark)

Nørager, Betina; Husic, Mirza; Møller, Jacob E

2004-01-01

BACKGROUND: Wall-motion analysis during low-dose dobutamine echocardiography (LDDE) is a semiquantitative measure of left ventricular contractile reserve after myocardial infarction (MI). The Doppler echocardiographic myocardial performance index (MPI) is a quantitative measure of combined left...

Gestational changes in left ventricular myocardial contractile function: new insights from two-dimensional speckle tracking echocardiography.

Science.gov (United States)

Sengupta, Shantanu P; Bansal, Manish; Hofstra, Leonard; Sengupta, Partho P; Narula, Jagat

2017-01-01

The goal of this study was to evaluate the impact of pregnancy and labor on left ventricular (LV) myocardial mechanics using speckle tracking echocardiography (STE). Pregnancy is characterized by profound hormonal and hemodynamic alterations that directly or indirectly influence cardiac structure and function. However, the impact of these changes on left ventricular (LV) myocardial contractile function has not been fully elucidated. In this prospective, longitudinal study, 35 pregnant women underwent serial clinical and echocardiographic evaluation during each trimester and at labor. Two dimensional STE was performed to measure global LV longitudinal, circumferential and radial strain (GLS, GCS and GRS, respectively). Similar data obtained from 20 nulliparous, age-matched women were used as control. All strain values during pregnancy were adjusted for age and hemodynamic parameters. There was a progressive increase in heart rate, systolic and diastolic blood pressure, cardiac output and LV stroke-work during pregnancy. LV end-diastolic and end-systolic volumes also increased progressively but LV ejection fraction remained unaltered, except for slight reduction during the second trimester. Compared to the controls, GLS and GCS were reduced in the first trimester itself (GLS -22.39 ± 5.43 % vs. -18.66 ± 0.64 %, P 0.0002; GCS -20.84 ± 3.20 vs. -17.88 ± 0.09, P counterbalancing changes in the myocardial mechanics. LV longitudinal and circumferential strain are reduced whereas radial strain is increased. These counterbalancing changes serve to maintain overall LV ejection performance within a normal range and enable the maternal heart to meet the hemodynamic demands of pregnancy and labor.

Normal nonuniformity of left ventricular contraction. Assessment by cine MR imaging with presaturation myocardial tagging

International Nuclear Information System (INIS)

Naito, H.; Arisawa, J.; Harada, K.; Yamagami, H.; Kozuka, T.; Tamura, S.

1996-01-01

Purpose: To identify the normal performance of left ventricular (LV) regional contraction using cine MR imaging with presaturation myocardial tagging. Material and Methods: Sixteen normal volunteers were examined on a 1.5 T MR system with tagging cine sequences. Tags were applied at end-diastole as 2 parallel black lines on short-axis and 4-chamber sections, and the fractional shortenings were calculated at 7 LV locations. Results: The following results were obtained with significance: A transmural gradient of contractility in the short-axis section; prolonged late-systolic endocardial shortening and epicardial early termination in the free wall; initial delay of shortening in the anterior wall; apical predominance of contractility; predominance of circumferential shortening in the free wall and of meridional shortening in the septum. These findings could be associated with myocardial fiber architecture, presumed wall stress and temporal asynergy of excitation. Conclusion: Cine MR imaging with myocardial tagging proved to be useful in assessing the nonuniformity of LV contraction. (orig.)

The effect of N-acetylcysteine on cardiac contractility to dobutamine in rats with streptozotocin-induced diabetes.

Science.gov (United States)

Cheng, Xing; Xia, Zhengyuan; Leo, Joyce M; Pang, Catherine C Y

2005-09-05

We examined if myocardial depression at the acute phase of diabetes (3 weeks after injection of streptozotocin, 60 mg/kg i.v.) is due to activation of inducible nitric oxide synthase and production of peroxynitrite, and if treatment with N-acetylcysteine (1.2 g/day/kg for 3 weeks, antioxidant) improves cardiac function. Four groups of rats were used: control, N-acetylcysteine-treated control, diabetic and N-acetylcysteine-treated diabetic. Pentobarbital-anaesthetized diabetic rats, relative to the controls, had reduced left ventricular contractility to dobutamine (1-57 microg/min/kg). The diabetic rats also had increased myocardial levels of thiobarbituric acid reactive substances, immunostaining of inducible nitric oxide synthase and nitrotyrosine, and similar baseline 15-F2t-isoprostane. N-acetylcysteine did not affect responses in the control rats; but increased cardiac contractility to dobutamine, reduced myocardial immunostaining of inducible nitric oxide synthase and nitrotyrosine and level of 15-F2t-isoprostane, and increased cardiac contractility to dobutamine in the diabetic rats. Antioxidant supplementation in diabetes reduces oxidative stress and improves cardiac function.

Maternal protein restriction compromises myocardial contractility in the young adult rat by changing proteins involved in calcium handling.

Science.gov (United States)

de Belchior, Aucelia C S; Freire, David D; da Costa, Carlos P; Vassallo, Dalton V; Padilha, Alessandra S; Dos Santos, Leonardo

2016-02-01

Maternal protein restriction (MPR) during pregnancy is associated with increased cardiovascular risk in the offspring in adulthood. In this study we evaluated the cardiac function of young male rats born from mothers subjected to MPR during pregnancy, focusing on the myocardial mechanics and calcium-handling proteins. After weaning, rats received normal diet until 3 mo old, when the following parameters were assessed: arterial and left ventricular hemodynamics and in vitro cardiac contractility in isolated papillary muscles. The body weight was lower and arterial pressure higher in the MPR group compared with young adult offspring of female rats that received standard diet (controls); and left ventricle time derivatives increased in the MPR group. The force developed by the cardiac muscle was similar; but time to peak and relaxation time were longer, and the derivatives of force were depressed in the MPR. In addition, MPR group exhibited decreased post-pause potentiation of force, suggesting reduced reuptake function of the sarcoplasmic reticulum. Corroborating, the myocardial content of SERCA-2a and phosphorylated PLB-Ser16/total PLB ratio was decreased and sodium-calcium exchanger was increased in the MPR group. The contraction dependent on transsarcolemmal influx of calcium was higher in MPR if compared with the control group. In summary, young rats born from mothers subjected to protein restriction during pregnancy exhibit changes in the myocardial mechanics with altered expression of calcium-handling proteins, reinforcing the hypothesis that maternal malnutrition is related to increased cardiovascular risk in the offspring, not only for hypertension, but also cardiac dysfunction. Copyright © 2016 the American Physiological Society.

Operative contractility: a functional concept of the inotropic state.

Science.gov (United States)

Curiel, Roberto; Perez-Gonzalez, Juan; Torres, Edwar; Landaeta, Ruben; Cerrolaza, Miguel

2005-10-01

1. Initial unsuccessful attempts to evaluate ventricular function in terms of the 'heart as a pump' led to focusing on the 'heart as a muscle' and to the concept of myocardial contractility. However, no clinically ideal index exists to assess the contractile state. The aim of the present study was to develop a mathematical model to assess cardiac contractility. 2. A tri-axial system was conceived for preload (PL), afterload (AL) and contractility, where stroke volume (SV) was represented as the volume of the tetrahedron. Based on this model, 'operative' contractility ('OperCon') was calculated from the readily measured values of PL, AL and SV. The model was tested retrospectively under a variety of different experimental and clinical conditions, in 71 studies in humans and 29 studies in dogs. A prospective echocardiographic study was performed in 143 consecutive subjects to evaluate the ability of the model to assess contractility when SV and PL were measured volumetrically (mL) or dimensionally (cm). 3. With inotropic interventions, OperCon changes were comparable to those of ejection fraction (EF), velocity of shortening (Vcf) and dP/dt-max. Only with positive inotropic interventions did elastance (Ees) show significantly larger changes. With load manipulations, OperCon showed significantly smaller changes than EF and Ees and comparable changes to Vcf and dP/dt-max. Values of OperCon were similar when AL was represented by systolic blood pressure or wall stress and when volumetric or dimensional values were used. 4. Operative contractility is a reliable, simple and versatile method to assess cardiac contractility.

Hydrogen ion changes and contractile behavior in the perfused rat heart

NARCIS (Netherlands)

Cingolani, H.E.; Maas, A.H.J.; Zimmerman, A.N.E.; Meijler, F.L.

1975-01-01

The effect of acid-base alterations was analyzed using isolated rat hearts perfused at constant coronary perfusion pressure, and stimulated to contract at constant rate. The amount of shortening in the major axis and its derivative were measured to assess myocardial contractility. Both the

Regional Longitudinal Myocardial Deformation Provides Incremental Prognostic Information in Patients with ST-Segment Elevation Myocardial Infarction.

Directory of Open Access Journals (Sweden)

Tor Biering-Sørensen

Full Text Available Global longitudinal systolic strain (GLS has recently been demonstrated to be a superior prognosticator to conventional echocardiographic measures in patients after myocardial infarction (MI. The aim of this study was to evaluate the prognostic value of regional longitudinal myocardial deformation in comparison to GLS, conventional echocardiography and clinical information.In total 391 patients were admitted with ST-Segment elevation myocardial infarction (STEMI, treated with primary percutaneous coronary intervention and subsequently examined by echocardiography. All patients were examined by tissue Doppler imaging (TDI and two-dimensional strain echocardiography (2DSE.During a median-follow-up of 5.3 (IQR 2.5-6.1 years the primary endpoint (death, heart failure or a new MI was reached by 145 (38.9% patients. After adjustment for significant confounders (including conventional echocardiographic parameters and culprit lesion, reduced longitudinal performance in the anterior septal and inferior myocardial regions (but not GLS remained independent predictors of the combined outcome. Furthermore, inferior myocardial longitudinal deformation provided incremental prognostic information to clinical and conventional echocardiographic information (Harrell's c-statistics: 0.63 vs. 0.67, p = 0.032. In addition, impaired longitudinal deformation outside the culprit lesion perfusion region was significantly associated with an adverse outcome (p<0.05 for all deformation parameters.Regional longitudinal myocardial deformation measures, regardless if determined by TDI or 2DSE, are superior prognosticators to GLS. In addition, impaired longitudinal deformation in the inferior myocardial segment provides prognostic information over and above clinical and conventional echocardiographic risk factors. Furthermore, impaired longitudinal deformation outside the culprit lesion perfusion region seems to be a paramount marker of adverse outcome.

[The cardioprotective action of the anticonvulsant preparation sodium valproate in disorders of cardiac contractile function caused by acute myocardial infarct in rats].

Science.gov (United States)

Belkina, L M; Korchazhkina, N B; Kamskova, Iu G; Fomin, N A

1997-01-01

The preventive and therapeutical effects of sodium valproate (SV), 200 mg/kg, on cardiac contractile disorders (developed pressure, rate-pressure products, dp/dt) were studied in rats having 2-day myocardial infarction (MI). The postinfarction rather than preinfarction use of SV substantially restricted the depressed resting left ventricular function. Given by two regimens, SV increased cardiac resistance to the maximum isometric load induced by 60-sec ligation of the ascending aorta. The cardioprotective effect of the drug was shown due to its positive chronotropic action rather than its inotropic one. Thus, SV may be used as an effective drug for the prevention and treatment of postinfarct cardiac dysfunctions.

Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

International Nuclear Information System (INIS)

Nakajima, Hiroshi; Onishi, Katsuya; Kurita, Tairo

2010-01-01

Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years ±10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07±0.62 ml min -1 g -1 , whereas stress MBF was 3.15±1.93 ml min -1 g -1 and the MPR was 3.33±1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, β=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, β=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia. (author)

Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

Energy Technology Data Exchange (ETDEWEB)

Nakajima, Hiroshi; Onishi, Katsuya; Kurita, Tairo [Mie Univ., Graduate School of Medicine, Tsu, Mie (Japan)

2010-11-15

Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years {+-}10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07{+-}0.62 ml min{sup -1} g{sup -1}, whereas stress MBF was 3.15{+-}1.93 ml min{sup -1} g{sup -1} and the MPR was 3.33{+-}1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, {beta}=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, {beta}=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia. (author)

Milrinone and levosimendan administered after reperfusion improve myocardial stunning in swine.

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Shibata, Itsuko; Cho, Sungsam; Yoshitomi, Osamu; Ureshino, Hiroyuki; Maekawa, Takuji; Hara, Tetsuya; Sumikawa, Koji

2013-02-01

We assessed the effect of milrinone application timing after reperfusion against myocardial stunning as compared with levosimendan in swine. Furthermore, we examined the role of p38 mitogen-activated protein kinase (p38 MAPK) in the milrinone-induced cardioprotection. All swine were subjected to 12-minutes ischemia followed by 90-minutes reperfusion to generate stunned myocardium. Milrinone or levosimendan was administered intravenously either for 20 minutes starting just after reperfusion or for 70 minutes starting 20 minutes after reperfusion. In another group, SB203580, a selective p38 MAPK inhibitor, was administered with and without milrinone. Regional myocardial contractility was assessed by percent segment shortening (%SS). Milrinone starting just after reperfusion, but not starting 20 minutes after reperfusion, improved %SS at 30, 60, and 90 minutes after reperfusion compared with that in the control group. SB203580 abolished the beneficial effect of milrinone. On the other hand, levosimendan starting 20 minutes after reperfusion, but not for 20 minutes starting just after reperfusion, improved %SS at 60 and 90 minutes after reperfusion. Milrinone should be administered just after reperfusion to protect myocardial stunning through p38 MAPK, whereas levosimendan improvement of contractile function could be mainly dependent on its positive inotropic effect.

Regional myocardial perfusion of cardioplegic solutions

International Nuclear Information System (INIS)

Eugene, J.; Lyons, K.P.; Ott, R.A.; Gelezunas, V.L.; Chang, C.W.; Kowall, M.G.; Haiduc, N.J.

1987-01-01

We compared the regional myocardial perfusion of blood cardioplegic solution (BCP) and crystalloid cardioplegic solution (CCP) in 14 mongrel dogs. Cardiopulmonary bypass was established at 28 degrees C, and a hydraulic occluder was placed around the proximal left anterior descending (LAD) coronary artery. In group 1 (N = 7) collateral coronary arteries were ligated; in group 2 (N = 7) collateral coronary arteries were left in situ. After the aorta was clamped, BCP and CCP were alternately perfused at 200 ml/min. The occluder was inflated to produce moderate, severe, and critical LAD stenosis, and regional perfusion was measured by xenon-133 washout with the Silicon Avalanche Radiation Detector. BCP infusion produced a consistently higher aortic pressure, but CCP flow was better than BCP flow under all conditions, particularly without coronary collaterals. Regional myocardial perfusion of CCP is superior to BCP

Na+/Ca2+ exchanger inhibition exerts a positive inotropic effect in the rat heart, but fails to influence the contractility of the rabbit heart

OpenAIRE

Farkas, A S; Acsai, K; Nagy, N; Tóth, A; Fülöp, F; Seprényi, G; Birinyi, P; Nánási, P P; Forster, T; Csanády, M; Papp, J G; Varró, A; Farkas, A

2008-01-01

Background and purpose: The Na+/Ca2+ exchanger (NCX) may play a key role in myocardial contractility. The operation of the NCX is affected by the action potential (AP) configuration and the intracellular Na+ concentration. This study examined the effect of selective NCX inhibition by 0.1, 0.3 and 1.0 μM SEA0400 on the myocardial contractility in the setting of different AP configurations and different intracellular Na+ concentrations in rabbit and rat hearts.

MRS algorithm: a new method for searching myocardial region in SPECT myocardial perfusion images.

Science.gov (United States)

He, Yuan-Lie; Tian, Lian-Fang; Chen, Ping; Li, Bin; Mao, Zhong-Yuan

2005-10-01

First, the necessity of automatically segmenting myocardium from myocardial SPECT image is discussed in Section 1. To eliminate the influence of the background, the optimal threshold segmentation method modified for the MRS algorithm is explained in Section 2. Then, the image erosion structure is applied to identify the myocardium region and the liver region. The contour tracing method is introduced to extract the myocardial contour. To locate the centriod of the myocardium, the myocardial centriod searching method is developed. The protocol of the MRS algorithm is summarized in Section 6. The performance of the MRS algorithm is investigated and the conclusion is drawn in Section 7. Finally, the importance of the MRS algorithm and the improvement of the MRS algorithm are discussed.

Abnormal myocardial capillary density in apical hypertrophic cardiomyopathy can be assessed by myocardial contrast echocardiography

International Nuclear Information System (INIS)

Moon, Jeonggeun; Cho, In-Jeong; Shim, Chi-Young; Ha, Jong-Won; Jang, Yangsoo; Chung, Namsik; Rim, Se-Joong

2010-01-01

Myocardial ischemia and dysfunction can occur in hypertrophic cardiomyopathy (HCM) because of the high muscle-to-blood ratio, even without significant coronary artery disease. Microbubbles reside only in the intravascular space and myocardial video-intensity during systole results mostly from microbubbles within capillaries. The hypothesis explored in the present study was that an abnormal capillary density in apical HCM (ApHCM) can be demonstrated using myocardial contrast echocardiography (MCE). The 56 patients were investigated (31 males, age 58±9 years; 33 ApHCM, 9 hypertensive left ventricular hypertrophy [LVH], 14 controls). MCE was performed with low-mechanical-index power modulation imaging. Tissue Doppler imaging to assess myocardial contractile function was obtained at the mitral annulus (S'), and 99m Tc-MIBI single photon emission computed tomography (SPECT) was also performed. All ApHCM patients exhibited perfusion defects at the hypertrophied segments in the systolic phase during MCE, whereas SPECT showed normal or rather increased perfusion at those sites. The cyclic variation of video-intensity was exaggerated in ApHCM when compared with the LVH or control group (% of [systolic video-intensity]/[diastolic video-intensity]: 33.0±12.3%, 88.3±19.2% and 79.4±13.9%, respectively [P<0.05]). Concurrently, MCE cyclic variation and perfusion defect size were related to decreased S' (P<0.05 for all). A perfusion defect at the hypertrophied segment, representing abnormal myocardial capillary density, was observed in ApHCM patients during MCE. The extent of MCE cyclic variation and the perfusion defect size both correlate with decreased myocardial contractile property in ApHCM. (author)

Effects of hot shot (non cardioplegic blood based) on cardiac contractility and rhythm as parameters of myocardial protection in cabg surgery abstract objective

International Nuclear Information System (INIS)

Janjua, A.M.; Iqbal, M.A.; Rashid, A.

2012-01-01

To compare the effects of warm blood cardioplegia along with hot shot (non-cardioplegic blood based) at the end of ischemic time to warm blood cardioplegia without hot shot to assess resumption of effective electromechanical activity and need for internal electrical cardioversion as indicators of myocardial protection and preservation. Study Design: Randomized control trial. Place and Duration: The study was conducted at Armed Forces Institute of Cardiology (AFIC), Rawalpindi for a period of 10 months (March 2009 - Dec 2009). Patients and Methods: Total 100 patients of coronary artery disease having coronary artery bypass grafting (CABG) surgery were equally and randomly divided into two groups using random numbers table. Group A (n=50), consisted of warm blood cardioplegia with non cardioplegic blood based hot shot and group B (n=50), consisted of warm blood cardioplegia only. The adequacy of myocardial protection techniques was assessed by noting the time interval (in seconds) between declamping of the ascending aorta and patient regaining electromechanical activity. Additional parameters were rhythm, use of internal cardiac defibrillation, inotropes, IABP requirement and ECG evidenced peri-op MI. Results: Average age in group A was 56.98 +- 9.47 years and in Group B it was 59.1 9.35 years. In group A there were 48 (96%) males and group B there were 43 (86%) males with p-value of 0.081. Comparison of preoperative variables of both the groups revealed no difference in cross clamp time (p=0.52), CPB time (p = 0.68) and endarterectomy (p=0.55). The electromechanical activity (contractility of heart) returned within 7.53 +- 2.09 min in group A as compared to 9.81 +- 2.6 min in group B (p<0.001). Significantly high frequency was observed for defibrillation (p=0.025), inotropic support (p=0.045) and IABP insertion (p=0.041) in group B as compared to group A. Conclusion: In CABG surgery the additional use of hot shot (non cardioplegic blood based) during cardiopulmonary

Exercise training prior to myocardial infarction attenuates cardiac deterioration and cardiomyocyte dysfunction in rats

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Luiz Henrique Marchesi Bozi

2013-04-01

Full Text Available OBJECTIVES: The present study was performed to investigate 1 whether aerobic exercise training prior to myocardial infarction would prevent cardiac dysfunction and structural deterioration and 2 whether the potential cardiac benefits of aerobic exercise training would be associated with preserved morphological and contractile properties of cardiomyocytes in post-infarct remodeled myocardium. METHODS: Male Wistar rats underwent an aerobic exercise training protocol for eight weeks. The rats were then assigned to sham surgery (SHAM, sedentary lifestyle and myocardial infarction or exercise training and myocardial infarction groups and were evaluated 15 days after the surgery. Left ventricular tissue was analyzed histologically, and the contractile function of isolated myocytes was measured. Student's t-test was used to analyze infarct size and ventricular wall thickness, and the other parameters were analyzed by the Kruskal-Wallis test followed by Dunn's test or a one-way analysis of variance followed by Tukey's test (p<0.05. RESULTS: Myocardial infarctions in exercise-trained animals resulted in a smaller myocardial infarction extension, a thicker infarcted wall and less collagen accumulation as compared to myocardial infarctions in sedentary animals. Myocardial infarction-induced left ventricular dilation and cardiac dysfunction, as evaluated by +dP/dt and -dP/dt, were both prevented by previous aerobic exercise training. Moreover, aerobic exercise training preserved cardiac myocyte shortening, improved the maximum shortening and relengthening velocities in infarcted hearts and enhanced responsiveness to calcium. CONCLUSION: Previous aerobic exercise training attenuated the cardiac dysfunction and structural deterioration promoted by myocardial infarction, and such benefits were associated with preserved cardiomyocyte morphological and contractile properties.

Separate effects of ischemia, hypoxia, and contractility on thallium-201 kinetics in rabbit myocardium

International Nuclear Information System (INIS)

Leppo, J.A.; Macneil, P.B.; Moring, A.F.; Apstein, C.S.

1986-01-01

The effects of hypoxia and ischemia, as well as altered contractility, on thallium-201 ( 201 TI) kinetics were evaluated in 42 isolated isovolumetrically contracting rabbit hearts. In Group A, three subgroups (n = 7 each) were studied that had either normal flow and oxygenation, hypoxia and normal flow, or ischemic flow and normal perfusate oxygen content. In Group B, three subgroups (n = 7 each) were studied and all hearts had normal flow but the contractile state was either enhanced with isoproterenol or impaired by hypocalcemia. A hemoglobin-free buffer perfusate was used in all experiments and multiple timed collections of arterial and coronary sinus effluent were used to model myocardial isotope activity during 30 min of constant uptake followed by 30 min of tracer clearance. During ischemia, hypoxia and hypocalcemia peak developed pressure and peak positive and negative dP/dt were all significantly reduced when compared to normal hemodynamic parameters (p less than 0.01). As expected, isoproterenol significantly elevated these parameters (p less than 0.04). Myocardial 201 TI kinetics were adequately described utilizing a bi-exponential model having a fast and slow component. Only ischemic hearts had significantly lower rate constants for 201 TI uptake and clearance than normal hearts (p less than 0.001). The mean (+/- s.d.) myocardial uptake and clearance rates for 201 TI (%/min) varied between 4.86 +/- 0.87 and 7.18 +/- 1.45 for the remaining groups of hearts. Therefore, myocardial 201 TI kinetics appear to be dominated by coronary flow and may not reflect marked alterations in the metabolic and contractile state. These data suggest that normal 201 TI uptake in impaired or hypercontractile cells, receiving normal flow, may not represent normal cellular function

Quantitative circumferential strain analysis using adenosine triphosphate-stress/rest 3-T tagged magnetic resonance to evaluate regional contractile dysfunction in ischemic heart disease

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Nakamura, Masashi, E-mail: m.nakamura1230@gmail.com [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan); Kido, Tomoyuki [Department of Radiology, Saiseikai Matsuyama Hospital, Ehime 791-0295 (Japan); Kido, Teruhito; Tanabe, Yuki; Matsuda, Takuya; Nishiyama, Yoshiko; Miyagawa, Masao; Mochizuki, Teruhito [Department of Radiology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime 791-0295 (Japan)

2015-08-15

Highlights: • Infarcted segments could be differentiated from non-ischemic and ischemic segments with high sensitivity and specificity under at rest conditions. • The time-to-peak circumferential strain values in infarcted segments were more significantly delayed than those in non-ischemic and ischemic segments. • Both circumferential strain and circumferential systolic strain rate values under ATP-stress conditions were significantly lower in ischemic segments than in non-ischemic segments. • Subtracting stress and rest circumferential strain had a higher diagnostic capability for ischemia relative to only utilizing rest or ATP-stress circumferential strain values. • A circumferential strain analysis using tagged MR can quantitatively assess contractile dysfunction in ischemic and infarcted myocardium. - Abstract: Purpose: We evaluated whether a quantitative circumferential strain (CS) analysis using adenosine triphosphate (ATP)-stress/rest 3-T tagged magnetic resonance (MR) imaging can depict myocardial ischemia as contractile dysfunction during stress in patients with suspected coronary artery disease (CAD). We evaluated whether it can differentiate between non-ischemia, myocardial ischemia, and infarction. We assessed its diagnostic performance in comparison with ATP-stress myocardial perfusion MR and late gadolinium enhancement (LGE)-MR imaging. Methods: In 38 patients suspected of having CAD, myocardial segments were categorized as non-ischemic (n = 485), ischemic (n = 74), or infarcted (n = 49) from the results of perfusion MR and LGE-MR. The peak negative CS value, peak circumferential systolic strain rate (CSR), and time-to-peak CS were measured in 16 segments. Results: A cutoff value of −12.0% for CS at rest allowed differentiation between infarcted and other segments with a sensitivity of 79%, specificity of 76%, accuracy of 76%, and an area under the curve (AUC) of 0.81. Additionally, a cutoff value of 477.3 ms for time-to-peak CS at rest

Regional Longitudinal Myocardial Deformation Provides Incremental Prognostic Information in Patients with ST-Segment Elevation Myocardial Infarction

DEFF Research Database (Denmark)

Biering-Sorensen, Tor; Jensen, Jan Skov; Pedersen, Sune H

2016-01-01

deformation in comparison to GLS, conventional echocardiography and clinical information. Method In total 391 patients were admitted with ST-Segment elevation myocardial infarction (STEMI), treated with primary percutaneous coronary intervention and subsequently examined by echocardiography. All patients were...... information to clinical and conventional echocardiographic information (Harrell's c-statistics: 0.63 vs. 0.67, p = 0.032). In addition, impaired longitudinal deformation outside the culprit lesion perfusion region was significantly associated with an adverse outcome (p...). Conclusion Regional longitudinal myocardial deformation measures, regardless if determined by TDI or 2DSE, are superior prognosticators to GLS. In addition, impaired longitudinal deformation in the inferior myocardial segment provides prognostic information over and above clinical and conventional...

Facilitated ethanol metabolism promotes cardiomyocyte contractile dysfunction through autophagy in murine hearts.

Science.gov (United States)

Guo, Rui; Hu, Nan; Kandadi, Machender R; Ren, Jun

2012-04-01

Chronic drinking leads to myocardial contractile dysfunction where ethanol metabolism plays an essential role. Acetaldehyde, the main ethanol metabolite, mediates alcohol-induced cell injury although the underlying mechanism is still elusive. This study was designed to examine the mechanism involved in accelerated ethanol metabolism-induced cardiac defect with a focus on autophagy. Wild-type FVB and cardiac-specific overexpression of alcohol dehydrogenase mice were placed on a 4% nutrition-balanced alcohol diet for 8 weeks. Myocardial histology, immunohistochemistry, autophagy markers and signal molecules were examined. Expression of micro RNA miR-30a, a potential target of Beclin 1, was evaluated by real-time PCR. Chronic alcohol intake led to cardiac acetaldehyde accumulation, hypertrophy and overt autophagosome accumulation (LC3-II and Atg7), the effect of which was accentuated by ADH. Signaling molecules governing autophagy initiation including class III PtdIns3K, phosphorylation of mTOR and p70S6K were enhanced and dampened, respectively, following alcohol intake. These alcohol-induced signaling responses were augmented by ADH. ADH accentuated or unmasked alcohol-induced downregulation of Bcl-2, Bcl-xL and MiR-30a. Interestingly, ADH aggravated alcohol-induced p62 accumulation. Autophagy inhibition using 3-MA abolished alcohol-induced cardiomyocyte contractile anomalies. Moreover, acetaldehyde led to cardiomyocyte contractile dysfunction and autophagy induction, which was ablated by 3-MA. Ethanol or acetaldehyde increased GFP-LC3 puncta in H9c2 cells, the effect of which was ablated by 3-MA but unaffected by lysosomal inhibition using bafilomycin A(1), E64D and pepstatin A. In summary, these data suggested that facilitated acetaldehyde production via ADH following alcohol intake triggered cardiac autophagosome formation along with impaired lysosomal degradation, en route to myocardial defect.

Moderate ethanol administration accentuates cardiomyocyte contractile dysfunction and mitochondrial injury in high fat diet-induced obesity.

Science.gov (United States)

Yuan, Fang; Lei, Yonghong; Wang, Qiurong; Esberg, Lucy B; Huang, Zaixing; Scott, Glenda I; Li, Xue; Ren, Jun

2015-03-18

Light to moderate drinking confers cardioprotection although it remains unclear with regards to the role of moderate drinking on cardiac function in obesity. This study was designed to examine the impact of moderate ethanol intake on myocardial function in high fat diet intake-induced obesity and the mechanism(s) involved with a focus on mitochondrial integrity. C57BL/6 mice were fed low or high fat diet for 16 weeks prior to ethanol challenge (1g/kg/d for 3 days). Cardiac contractile function, intracellular Ca(2+) homeostasis, myocardial histology, and mitochondrial integrity [aconitase activity and the mitochondrial proteins SOD1, UCP-2 and PPARγ coactivator 1α (PGC-1α)] were assessed 24h after the final ethanol challenge. Fat diet intake compromised cardiomyocyte contractile and intracellular Ca(2+) properties (depressed peak shortening and maximal velocities of shortening/relengthening, prolonged duration of relengthening, dampened intracellular Ca(2+) rise and clearance without affecting duration of shortening). Although moderate ethanol challenge failed to alter cardiomyocyte mechanical property under low fat diet intake, it accentuated high fat diet intake-induced changes in cardiomyocyte contractile function and intracellular Ca(2+) handling. Moderate ethanol challenge failed to affect fat diet intake-induced cardiac hypertrophy as evidenced by H&E staining. High fat diet intake reduced myocardial aconitase activity, downregulated levels of mitochondrial protein UCP-2, PGC-1α, SOD1 and interrupted intracellular Ca(2+) regulatory proteins, the effect of which was augmented by moderate ethanol challenge. Neither high fat diet intake nor moderate ethanol challenge affected protein or mRNA levels as well as phosphorylation of Akt and GSK3β in mouse hearts. Taken together, our data revealed that moderate ethanol challenge accentuated high fat diet-induced cardiac contractile and intracellular Ca(2+) anomalies as well as mitochondrial injury. Copyright �

Leucocyte depletion attenuates the early increase in myocardial capillary permeability to small hydrophilic solutes following ischaemia and reperfusion

DEFF Research Database (Denmark)

Svendsen, Jesper Hastrup; Hansen, P R; Ali, S

1993-01-01

The aim was to assess the significance of polymorphonuclear leucocytes on the myocardial capillary permeability to a small hydrophilic indicator, on the vascular tone of the resistance vessels, and on contractile function following ischaemia and reperfusion.......The aim was to assess the significance of polymorphonuclear leucocytes on the myocardial capillary permeability to a small hydrophilic indicator, on the vascular tone of the resistance vessels, and on contractile function following ischaemia and reperfusion....

The effect of device-based cardiac contractility modulation therapy on myocardial efficiency and oxidative metabolism in patients with heart failure

International Nuclear Information System (INIS)

Goliasch, Georg; Khorsand, Aliasghar; Sochor, Heinz; Schmidinger, Herwig; Graf, Senta; Schuetz, Matthias; Karanikas, Georgios; Khazen, Cesar; Wolzt, Michael

2012-01-01

Cardiac contractility modulation (CCM) is a device-based therapy that involves delivery of nonexcitatory electrical signals resulting in improved ventricular function and a reversal of maladaptive cardiac fetal gene programmes. Our aim was to evaluate whether acute application of CCM leads to an increase in myocardial oxygen consumption (MVO 2 ) in patients with chronic heart failure using 11 C-acetate positron emission tomography (PET). We prospectively enrolled 21 patients with severe heart failure. 11 C-acetate PET was performed before and after activation of the CCM device. In 12 patients an additional stress study with dobutamine was performed. Under resting conditions, the values of myocardial blood flow (MBF), MVO 2 and work metabolic index (WMI, reflecting myocardial efficiency) with the CCM device activated did not differ significantly from the values with the device deactivated. MBF was 0.81 ± 0.18 ml min -1 g -1 with the device off and 0.80 ± 0.15 ml min -1 g -1 with the device on (p = 0.818), MVO 2 was 6.81 ± 1.69 ml/min/100 g with the device off and 7.15 ± 1.62 ml/min/100 g with the device on (p = 0.241) and WMI was 4.94 ± 1.14 mmHg ml/m 2 with the device off and 5.21 ± 1.36 mmHg ml/m 2 with the device on (p = 0.344). Under dobutamine stress, the values of MBF, MVO 2 and WMI with the CCM device activated did not differ from the values with the device deactivated, but were significantly increased compared with the values obtained under resting conditions. These results indicate that CCM does not induce increased MVO 2 , even under stress conditions. (orig.)

The effect of device-based cardiac contractility modulation therapy on myocardial efficiency and oxidative metabolism in patients with heart failure

Energy Technology Data Exchange (ETDEWEB)

Goliasch, Georg; Khorsand, Aliasghar; Sochor, Heinz; Schmidinger, Herwig; Graf, Senta [Vienna General Hospital/Medical University of Vienna, Department of Cardiology, Vienna (Austria); Schuetz, Matthias; Karanikas, Georgios [Vienna General Hospital/Medical University of Vienna, Department of Nuclear Medicine, Vienna (Austria); Khazen, Cesar [Vienna General Hospital/ Medical University of Vienna, Department of Cardiothoracic Surgery, Vienna (Austria); Wolzt, Michael [Vienna General Hospital/Medical University of Vienna, Department of Cardiology, Vienna (Austria); Vienna General Hospital/ Medical University of Vienna, Department of Clinical Pharmacology, Vienna (Austria)

2012-03-15

Cardiac contractility modulation (CCM) is a device-based therapy that involves delivery of nonexcitatory electrical signals resulting in improved ventricular function and a reversal of maladaptive cardiac fetal gene programmes. Our aim was to evaluate whether acute application of CCM leads to an increase in myocardial oxygen consumption (MVO{sub 2}) in patients with chronic heart failure using {sup 11}C-acetate positron emission tomography (PET). We prospectively enrolled 21 patients with severe heart failure. {sup 11}C-acetate PET was performed before and after activation of the CCM device. In 12 patients an additional stress study with dobutamine was performed. Under resting conditions, the values of myocardial blood flow (MBF), MVO{sub 2} and work metabolic index (WMI, reflecting myocardial efficiency) with the CCM device activated did not differ significantly from the values with the device deactivated. MBF was 0.81 {+-} 0.18 ml min{sup -1} g{sup -1} with the device off and 0.80 {+-} 0.15 ml min{sup -1} g{sup -1} with the device on (p = 0.818), MVO{sub 2} was 6.81 {+-} 1.69 ml/min/100 g with the device off and 7.15 {+-} 1.62 ml/min/100 g with the device on (p = 0.241) and WMI was 4.94 {+-} 1.14 mmHg ml/m{sup 2} with the device off and 5.21 {+-} 1.36 mmHg ml/m{sup 2} with the device on (p = 0.344). Under dobutamine stress, the values of MBF, MVO{sub 2} and WMI with the CCM device activated did not differ from the values with the device deactivated, but were significantly increased compared with the values obtained under resting conditions. These results indicate that CCM does not induce increased MVO{sub 2}, even under stress conditions. (orig.)

Estimation of regional myocardial sympathetic neuronal function with I-123 metaiodobenzylguanidine (MIBG) myocardial images in patients with cardiomyopathy

International Nuclear Information System (INIS)

Tanaka, Takeshi; Aizawa, Tadanori; Kato, Kazuzo; Nakano, Hajime; Igarashi, Masaki; Ueno, Takashi; Hirosawa, Koshichiro; Kusakabe, Kiyoko.

1989-01-01

Myocardial SPECT images with I-123 metaiodobenzylguanidine (MIBG) were obtained in 10 patients with cardiomyopathy under stable state. For myocardial imaging, MIBG and Tl-201 (Tl) were simultaneously injected and collected. The ratio of MIBG to Tl (M/T ratio) in ROI was obtained with 50% cut off levels in order to eliminate background activity. The patients were divided into three major groups: (l) those who had the M/T ratio ranging from 0.8 to l.20 at rest and had marked defects in the infero-lateral region on delayed MIBG images, where pathophysiologically accelerated regional sympathetic neuronal function was suspected (n=5), (II) those who had increased M/T ratios (l.6 and l.7) in the basal septal wall (n=3), and (III) those who had decreased M/T ratios (0.7 and 0.75) in the apical septal wall, where depletion of myocardial norepinephrine was suspected (n=2). These findings indicate the potential of myocardial MIBG images to evaluate myocardial distribution of norepinephrine, i.e. myocardial sympathetic neuronal function. Certain shortcomings, such as an increased background due to dual isotopes and an increased pulmonary uptake of MIBG, require further study on quantitative methods. (Namekawa, K)

IGF-1 Alleviates High Fat Diet-Induced Myocardial Contractile Dysfunction: Role of Insulin Signaling and Mitochondrial Function

Science.gov (United States)

Zhang, Yingmei; Yuan, Ming; Bradley, Katherine M.; Dong, Feng; Anversa, Piero; Ren, Jun

2012-01-01

Obesity is often associated with reduced plasma IGF-1 levels, oxidative stress, mitochondrial damage and cardiac dysfunction. This study was designed to evaluate the impact of IGF-1 on high fat diet-induced oxidative, myocardial, geometric and mitochondrial responses. FVB and cardiomyocyte-specific IGF-1 overexpression transgenic mice were fed a low (10%) or high fat (45%) diet to induce obesity. High fat diet feeding led to glucose intolerance, elevated plasma levels of leptin, interleukin-6, insulin and triglyceride as well as reduced circulating IGF-1 levels. Echocardiography revealed reduced fractional shortening, increased end systolic and diastolic diameter, increased wall thickness, and cardiac hypertrophy in high fat-fed FVB mice. High fat diet promoted ROS generation, apoptosis, protein and mitochondrial damage, reduced ATP content, cardiomyocyte cross-sectional area, contractile and intracellular Ca2+ dysregulation, including depressed peak shortening and maximal velocity of shortening/relengthening, prolonged duration of relengthening, and dampened intracellular Ca2+ rise and clearance. Western blot analysis revealed disrupted phosphorylation of insulin receptor, post-receptor signaling molecules IRS-1 (tyrosine/serine phosphorylation), Akt, GSK3β, Foxo3a, mTOR, as well as downregulated expression of mitochondrial proteins PPARγ coactivator 1α (PGC1α) and UCP-2. Intriguingly, IGF-1 mitigated high fat diet feeding-induced alterations in ROS, protein and mitochondrial damage, ATP content, apoptosis, myocardial contraction, intracellular Ca2+ handling and insulin signaling, but not whole body glucose intolerance and cardiac hypertrophy. Exogenous IGF-1 treatment also alleviated high fat diet-induced cardiac dysfunction. Our data revealed that IGF-1 alleviates high fat diet-induced cardiac dysfunction despite persistent cardiac remodeling, possibly due to preserved cell survival, mitochondrial function and insulin signaling. PMID:22275536

Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography

International Nuclear Information System (INIS)

Schelbert, H.R.; Phelps, M.E.

While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography ( 13 N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique

Effects of phosphodiesterase III inhibition on length-dependent regulation of myocardial function in coronary surgery patients

NARCIS (Netherlands)

de Hert, S. G.; ten Broecke, P. W.; Mertens, E.; Rodrigus, I. E.; Stockman, B. A.

2002-01-01

BACKGROUND: Phosphodiesterase III inhibitors increase myocardial contractility and decrease left ventricular (LV) afterload. We studied whether these effects altered LV response to an increase in cardiac load and affected length-dependent regulation of myocardial function. METHODS: Before the start

Pulmonary artery radiocardiography and rheography in the diagnosis of hemodynamic and contractile function impairments of the right ventricle in patients with obstructive bronchitis

International Nuclear Information System (INIS)

Paleev, N.P.; Cherejskaya, N.K.; Tsar'kova, L.N.; Baklykova, S.N.; Novoderezhkina, L.B.; Oblovatskaya, O.G.; Dubinina, E.B.

1990-01-01

Radiocardiography and rheography of the pulmonary artery were used to examine impairments in hemodynamics and contractile function of the right ventricle in 40 patients with chronic obstructive bronchitis complicated with persistent hypertension. Right ventricular hemodynamic and contractile impairments were shown to be not equivalent with similar clinical and functional signs of pulmonary hypertension. This fact indicates that the use of special techiques is of practical value in the determination of right ventricular hemodynamics and myocardial contractility in patients with chronic obstructive bronchitis. Radiocardiography and rheography of the pulmonary artery are sufficiently reliable noninvasive techniques for examining the hemodynamics and contractile function of the right ventricular myocardium

Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris

International Nuclear Information System (INIS)

Selwyn, A.P.; Forse, G.; Fox, K.; Jonathan, A.; Steiner, R.

1981-01-01

Fifty patients who presented with angina pectoris were studied to examine the disturbances of regional myocardial perfusion during stress. Each patient underwent 16-point precordial mapping of the ECG during an exercise test, and coronary and left ventricular angiography. Regional myocardial perfusion was assessed using an atrial pacing test and a short-lived radionuclide, krypton-81m. Eleven patients had negative exercise tests and uniform increases in myocardial activity of krypton-81m of 98 +/- 18.0% during pacing. Ten patients performed 30,000-43,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and increases in myocardial activity of krypton-81m to remote and jeopardized myocardium at the onset of pacing. However, further pacing produced a decrease in activity in the affected segment of 68.0 +/- 9.0% accompanied by ST-segment depression and angina. Twelve patients achieved 26,000-32,000 J in positive exercise tests and had significant coronary artery disease. Atrial pacing produced increased activity of krypton-81m to remote myocardium. The jeopardized segment at first showed no change and then a decrease in regional activity of krypton-81m (89.0 +/- 17%) accompanied by ST-segment depression and chest pain. Seventeen patients achieved only 7000-22,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and developed decreases in regional activity of krypton-81m to the affected segment of myocardium starting at the onset of atrial pacing and decreasing by 88 +/- 0 7.0% below control. We conclude that different patterns of disturbed myocardial distribution of krypton-81m are present during stress-induced ischemia in patients with coronary artery disease. There was a close temporal relationship between these disturbances and ST-segment depression

A comparative study of contractility of the heart ventricle in some ectothermic vertebrates

Directory of Open Access Journals (Sweden)

Sergey Kharin

2009-07-01

Full Text Available The purpose of this study was to analyze contractility of the heart ventricle in selected reptilian and amphibian species having the same ventricular excitation pattern. Systolic time intervals and indices of contractility of the heart ventricle were measured in anaesthetized frogs, snakes, and tortoises by use of polycardiography. The electromechanical delay was significantly shorter in tortoises compared with the other two species. The isovolumetric contraction time in frogs was approximately twofold longer than in reptiles. The pre-ejection period was the longest in frogs and the shortest in tortoises, whereas snakes were intermediate. The ejection time was slightly longer in tortoises compared with the other two species. The greatest isovolumetric contraction index and the smallest myocardial tension index corresponded to the frog and tortoise heart ventricle, respectively. The intrasystolic index in tortoises was significantly greater than in frogs, whereas quite similar to that in snakes. The frog ventricle had lower contractility compared with the reptilian one. Although ventricular contractility tended to be lower in snakes compared with tortoises, this difference was not statistically significant. Possible causes for these differences are discussed. We suppose a large variety in ventricular contractility among amphibian and reptilian species having the same ventricular activation pattern. This variety may be conditioned by heart anatomy, intracardiac shunting, lifestyles, and habitats. It can only be hypothesized that on the average, ventricular contractility is higher in reptiles compared with amphibians and in chelonians compared with snakes.

Non-Q-wave myocardial infarction: impaired myocardial energy metabolism in regions with reduced 99mTc-MIBI accumulation.

Science.gov (United States)

Moka, D; Baer, F M; Theissen, P; Schneider, C A; Dietlein, M; Erdmann, E; Schicha, H

2001-05-01

Reduced regional technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) accumulation in patients with chronic non-Q-wave infarction (NQWI) but without significant coronary artery stenosis indicates non-transmural damage of the myocardial wall. The aim of this study was to characterise cardiac energy metabolism after NQWI using phosphorus-31 magnetic resonance spectroscopy (31P-MRS) and to compare the biochemical remodelling with changes in regional 99mTc-MIBI uptake and with morphological and functional parameters assessed by magnetic resonance imaging (MRI). Fifteen patients with a history of NQWI, exclusion of significant coronary artery stenosis (energy metabolism. Spectroscopic measurements were performed in the infarct-related myocardial region. Corresponding gradient-echo MR images and myocardial 99mTc-MIBI single-photon emission tomography images were acquired for exact localisation of the infarct region. All examinations were performed at rest under anti-ischaemic medication. Data were compared with those of patients in whom coronary artery disease had been excluded by angiography (group B, n=10). All patients of group A displayed anterior wall hypokinesia in the infarcted area on both ventriculography and MRI, with a reduced myocardial accumulation of 99mTc-MIBI (66.3%+/-11.8% vs 95.6%+/-2.2% in group B). The mean wall thickness during the complete cardiac cycle (9.5+/-1.8 mm vs 13.1+/-1.1 mm in group B, Penergy metabolism.

Alcohol dehydrogenase accentuates ethanol-induced myocardial dysfunction and mitochondrial damage in mice: role of mitochondrial death pathway.

Directory of Open Access Journals (Sweden)

Rui Guo

2010-01-01

Full Text Available Binge drinking and alcohol toxicity are often associated with myocardial dysfunction possibly due to accumulation of the ethanol metabolite acetaldehyde although the underlying mechanism is unknown. This study was designed to examine the impact of accelerated ethanol metabolism on myocardial contractility, mitochondrial function and apoptosis using a murine model of cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were acutely challenged with ethanol (3 g/kg/d, i.p. for 3 days. Myocardial contractility, mitochondrial damage and apoptosis (death receptor and mitochondrial pathways were examined.Ethanol led to reduced cardiac contractility, enlarged cardiomyocyte, mitochondrial damage and apoptosis, the effects of which were exaggerated by ADH transgene. In particular, ADH exacerbated mitochondrial dysfunction manifested as decreased mitochondrial membrane potential and accumulation of mitochondrial O(2 (*-. Myocardium from ethanol-treated mice displayed enhanced Bax, Caspase-3 and decreased Bcl-2 expression, the effect of which with the exception of Caspase-3 was augmented by ADH. ADH accentuated ethanol-induced increase in the mitochondrial death domain components pro-caspase-9 and cytochrome C in the cytoplasm. Neither ethanol nor ADH affected the expression of ANP, total pro-caspase-9, cytosolic and total pro-caspase-8, TNF-alpha, Fas receptor, Fas L and cytosolic AIF.Taken together, these data suggest that enhanced acetaldehyde production through ADH overexpression following acute ethanol exposure exacerbated ethanol-induced myocardial contractile dysfunction, cardiomyocyte enlargement, mitochondrial damage and apoptosis, indicating a pivotal role of ADH in ethanol-induced cardiac dysfunction possibly through mitochondrial death pathway of apoptosis.

Alcohol dehydrogenase accentuates ethanol-induced myocardial dysfunction and mitochondrial damage in mice: role of mitochondrial death pathway.

Science.gov (United States)

Guo, Rui; Ren, Jun

2010-01-18

Binge drinking and alcohol toxicity are often associated with myocardial dysfunction possibly due to accumulation of the ethanol metabolite acetaldehyde although the underlying mechanism is unknown. This study was designed to examine the impact of accelerated ethanol metabolism on myocardial contractility, mitochondrial function and apoptosis using a murine model of cardiac-specific overexpression of alcohol dehydrogenase (ADH). ADH and wild-type FVB mice were acutely challenged with ethanol (3 g/kg/d, i.p.) for 3 days. Myocardial contractility, mitochondrial damage and apoptosis (death receptor and mitochondrial pathways) were examined. Ethanol led to reduced cardiac contractility, enlarged cardiomyocyte, mitochondrial damage and apoptosis, the effects of which were exaggerated by ADH transgene. In particular, ADH exacerbated mitochondrial dysfunction manifested as decreased mitochondrial membrane potential and accumulation of mitochondrial O(2) (*-). Myocardium from ethanol-treated mice displayed enhanced Bax, Caspase-3 and decreased Bcl-2 expression, the effect of which with the exception of Caspase-3 was augmented by ADH. ADH accentuated ethanol-induced increase in the mitochondrial death domain components pro-caspase-9 and cytochrome C in the cytoplasm. Neither ethanol nor ADH affected the expression of ANP, total pro-caspase-9, cytosolic and total pro-caspase-8, TNF-alpha, Fas receptor, Fas L and cytosolic AIF. Taken together, these data suggest that enhanced acetaldehyde production through ADH overexpression following acute ethanol exposure exacerbated ethanol-induced myocardial contractile dysfunction, cardiomyocyte enlargement, mitochondrial damage and apoptosis, indicating a pivotal role of ADH in ethanol-induced cardiac dysfunction possibly through mitochondrial death pathway of apoptosis.

Use of ultrafast computed tomography to quantitate regional myocardial perfusion: a preliminary report

International Nuclear Information System (INIS)

Rumberger, J.A.; Feiring, A.J.; Lipton, M.J.; Higgins, C.B.; Ell, S.R.; Marcus, M.L.

1987-01-01

The purpose of this study was to assess the potential for rapid acquisition computed axial tomography (Imatron C-100) to quantify regional myocardial perfusion. Myocardial and left ventricular cavity contrast clearance curves were constructed after injecting nonionic contrast (1 ml/kg over 2 to 3 seconds) into the inferior vena cava of six anesthetized, closed chest dogs (n = 14). Independent myocardial perfusion measurements were obtained by coincident injection of radiolabeled microspheres into the left atrium during control, intermediate and maximal myocardial vasodilation with adenosine (0.5 to 1.0 mg/kg per min, intravenously, respectively). At each flow state, 40 serial short-axis scans of the left ventricle were taken near end-diastole at the midpapillary muscle level. Contrast clearance curves were generated and analyzed from the left ventricular cavity and posterior papillary muscle regions after excluding contrast recirculation and minimizing partial volume effects. The area under the curve (gamma variate function) was determined for a region of interest placed within the left ventricular cavity. Characteristics of contrast clearance data from the posterior papillary muscle region that were evaluated included the peak myocardial opacification, area under the contrast clearance curve and a contrast clearance time defined by the full width/half maximal extent of the clearance curve. Myocardial perfusion (microspheres) ranged from 35 to 450 ml/100 g per min (mean 167 +/- 125)

Regional left ventricular contractile dynamics in hypertrophic cardiomyopathy estimated by magnetic resonance imaging

International Nuclear Information System (INIS)

Sato, Tetsuya

1994-01-01

To assess the regional myocardial function in hypertrophic cardiomyopathy (HCM), I examined the systolic wall thickening (%WT) and percent change of segmental wall area (%AR) using cine magnetic resonance imaging in 23 normal volunteers (G1) and 40 patients (G2) with HCM. Short axis images of the left ventricle were recorded at the base and the apex, and were divided into 5 segments, and %WT and %AR were measured for each segment. There were no significant differences in %WT and %AR among the segments in G1, while %WT of the posterior septum, posterior and lateral segments in the apex were higher than the corresponding segments of the base. Wall segments of G2 were classified into 3 groups according to the end-diastolic wall thickness: G2a, ≤12 mm; G2b, 12 15. At each slice level, %WT and %AR were highest in G2a and lowest in G2c. These findings suggest that myocardial shortening in normal subjects is higher in the apex than in the base, and, in HCM, regional myocardial function decreases in association with an advance of hypertrophy, with a possible compensatory increased wall function of normal segments. (author)

Contractility Dispersion in Long QT Syndrome

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MH Nikoo

2009-09-01

Full Text Available Background: Previous studies, using M mode echocardiography, provided unexpected evidence of a mechanical alteration in patients with long QT syndrome. The aim of this study was to evaluate entire left ventricular (LV wall motion characteristics in patients with long QT syndrome using tissue Doppler imaging. Methods: We enrolled 17 patients with congenital long QT syndrome [11 female and 6 male], aged 21 to 45 years. 10 subjects without cardiac disease were also selected as a control group. Two-dimensional tissue Doppler imaging (TDI recording of the LV was obtained from the basal and mid-segments from apical four-chamber, two-chamber, and long-axis views. ‘Myocardial Contraction Duration’ [MCD] was defined as the time from start of R wave on ECG to end of S wave on TDI. MCD was measured in the six LV wall positions: septal, anteroseptal, lateral, inferior, posterior and anterior positions.Results: LV contractility dispersion was significantly greater in long QT syndrome patients compared to control group [0.051 ± 0.011 vs. 0.016 ± 0.06; P < 0.001]. Conclusion: Our study evaluated left ventricular dispersion of contractility duration in patients with long QT syndrome. This mechanical dispersion may be a reflection of the inhomogeneity of repolarisation in the long QT syndrome.

Relationship between segmental thallium-201 uptake and regional myocardial blood flow in patients with coronary artery disease

International Nuclear Information System (INIS)

Nichols, A.B.; Weiss, M.B.; Sciacca, R.R.; Cannon, P.J.; Blood, D.K.

1983-01-01

The relationship between the spatial distribution of thallium-201 in myocardial perfusion scintigrams and the distribution of left ventricular regional myocardial blood flow was examined in 25 patients undergoing coronary arteriography. Thallium-201 myocardial scintigrams were obtained after symptom-limited exercise and after a 4 hr delay. Regional myocardial blood flow was measured by the xenon-133 clearance method in patients at rest and during rapid atrial pacing to a double product comparable with that achieved during exercise stress testing. Patterns of regional thallium-201 activity and regional myocardial blood flow, recorded in similar left anterior oblique projections, were compared for left ventricular segments supplied by the left anterior descending (LAD) and left circumflex (CIRC) arteries. In 11 patients without significant lesions of the left coronary artery (group 1), thallium-201 was homogeneously distributed in the LAD and CIRC distributions in scintigrams taken during peak exercise; these scintigrams correspond to homogeneous regional myocardial blood flow in the LAD and CIRC regions during pacing-induced stress. In 14 patients with significant lesions of the left coronary artery (group 2), ratios of regional thallium-201 activity in the LAD and CIRC distributions of exercise scintigrams correlated well (r . .84) with ratios of regional myocardial blood flow measured during rapid pacing. Background subtraction altered the relationship between relative thallium-201 uptake and regional myocardial blood flow, causing overestimation of the magnitude of flow reduction on exercise scintigrams

Decreased perfusion in myocardial region of normal donor artery secondary to collateral development

International Nuclear Information System (INIS)

Koga, Y.; Takahashi, M.; Kojima, A.; Takaki, Y.; Tomiguchi, S.; Hirota, Y.; Kugiyama, K.; Yasue, H.; Hayasaki, K.; Kumamoto Saiseikai Hospital

1992-01-01

Thirty-one patients suffering from single vessel exertional angina with collaterals (Group A) were evaluated by stress 201 Tl myocardial emission CT (Tl-SPECT) with 16 controls of severely stenotic single vessel exertional angina without collaterals (Group B). Group A included 21 patients (68%) who showed an extensive perfusion defect in double artery myocardial regions, including the normal donor artery myocardial region (DMR). However, there were no such cases in Group B, giving a significant difference between these 2 groups (p < 0.001). Four patients in Group A, having a perfusion defect both in DMR and in the collateral dependent myocardial region (CMR) underwent a successful percutaneous transluminal coronary angioplasty (PTCA) with disappearance of collaterals. Tl-SPECT findings after PTCA showed no perfusion defect either in CMR or in DMR. This has been explained on the basis that the coronary collaterals stole blood and produced perfusion defect in DMR. (orig.)

Regional gastrointestinal contractility parameters using the wireless motility capsule

DEFF Research Database (Denmark)

Farmer, A D; Wegeberg, A-M L; Brock, B

2018-01-01

BACKGROUND: The wireless motility capsule concurrently measures temperature, pH and pressure as it traverses the gastrointestinal tract. AIMS: To describe normative values for motility/contractility parameters across age, gender and testing centres. METHODS: Healthy participants underwent...

Influence of high energy phosphate metabolism in postischemic myocardial dysfunction using magnetic resonance spectroscopy; Influencia dos fosfatos de alta energia na funcao ventricular em pacientes com infarto do miocardio avaliada pela resonancia magnetica

Energy Technology Data Exchange (ETDEWEB)

Kalil Filho, Roberto [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Hospital das Clinicas

1998-05-01

The recovery of left ventricular function after reperfusion is delayed in general by several hours, days or weeks and this phenomenon is known as myocardial stunning. One of the theories to explain the pathogenesis of this postischemic myocardial dysfunction is the production of not enough energy by mitochondria, leading to decreased adenosine-triphosphate (ATP) levels. We evaluated the influence of high energy phosphate metabolism in postischemic myocardial dysfunction, using magnetic resonance spectroscopy in patients with acute anterior wall myocardial infarction, successfully reperfused, within the first six hours from the onset of the symptoms. Twenty-nine patients were studied in the acute phase (on average four days after the onset of myocardial infarction) and 21 repeated the examination in the follow-up phase (average 39 days). Regional left ventricular function was evaluated by cine-resonance and high energy phosphate metabolism by phosphorus-31 spectroscopy, using the phosphocreatine {beta} ATP (P Cr/{beta}ATP) ratio. The existence of myocardial stunning was suggested by the improvement of the related regional contractility during the follow-up. The contractility improved in the septal wall from 2.46{+-} 0.68 to 1.54 {+-} 0.78 (p<0.001), in the anteroseptal wall from 2.0 {+-} 0.89 to 1.40 {+-} 0.75 (p<0.001) and in the anterior wall from 2.37 {+-} 0.71 to 1.41 {+-} 0.59 (p<0.001). The P Cr/{beta}ATP ratio did not change from acute to follow-up phase (1.51 {+-} 0.17 vs. 1.53 {+-} 0.17; p = 0.6). This study suggests that decreased high energy phosphate metabolism after reperfusion does not have an important role in the genesis of the myocardial stunning in patients with acute anterior wall myocardial infarction. (author) 25 refs., 9 figs., 1 tab.

The importance of myocardial contractile reserve in predicting response to cardiac resynchronization therapy

NARCIS (Netherlands)

Kloosterman, Mariëlle; Damman, Kevin; Van Veldhuisen, Dirk J; Rienstra, Michiel; Maass, Alexander H

AimTo perform a meta-analysis and systematic review of published data to assess the relationship between contractile reserve and response to cardiac resynchronization therapy (CRT) in patients with heart failure. Methods and resultsWe searched MEDLINE/PubMed and Cochrane for all papers published up

Low-intensity pulsed ultrasound enhances angiogenesis and ameliorates contractile dysfunction of pressure-overloaded heart in mice.

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Tsuyoshi Ogata

Full Text Available Chronic left ventricular (LV pressure overload causes relative ischemia with resultant LV dysfunction. We have recently demonstrated that low-intensity pulsed ultrasound (LIPUS improves myocardial ischemia in a pig model of chronic myocardial ischemia through enhanced myocardial angiogenesis. In the present study, we thus examined whether LIPUS also ameliorates contractile dysfunction in LV pressure-overloaded hearts.Chronic LV pressure overload was induced with transverse aortic constriction (TAC in mice. LIPUS was applied to the whole heart three times in the first week after TAC and was repeated once a week for 7 weeks thereafter (n = 22. Animals in the control groups received the sham treatment without LIPUS (n = 23. At 8 weeks after TAC, LV fractional shortening was depressed in the TAC-Control group, which was significantly ameliorated in the TAC-LIPUS group (30.4±0.5 vs. 36.2±3.8%, P<0.05. Capillary density was higher and perivascular fibrosis was less in the LV in the TAC-LIPUS group than in the TAC-Control group. Myocardial relative ischemia evaluated with hypoxyprobe was noted in the TAC-Control group, which was significantly attenuated in the TAC-LIPUS group. In the TAC-LIPUS group, as compared with the control group, mRNA expressions of BNP and collagen III were significantly lower (both P<0.05 and protein expressions of VEGF and eNOS were significantly up-regulated associated with Akt activation (all P<0.05. No adverse effect related to the LIPUS therapy was noted.These results indicate that the LIPUS therapy ameliorates contractile dysfunction in chronically pressure-overloaded hearts through enhanced myocardial angiogenesis and attenuated perivascular fibrosis. Thus, the LIPUS therapy may be a promising, non-invasive treatment for cardiac dysfunction due to chronic pressure overload.

Analysis of the relationship between myocardial viability and regional left ventricular wall motion

International Nuclear Information System (INIS)

Furutani, Yuhji; Ozaki, Masaharu; Yamamoto, Takeshi; Sato, Shinichi; Saiki, Atsushi; Kusukawa, Reizo

1993-01-01

Myocardial viability was determined by using postsystolic shortening (PSS) as an index, as obtained by cardiac blood pool scintigraphy with Tc-99m HSA. The findings were compared with those of thallium-201 myocardial SPECT. The study population was comparised of 41 patients with single blood vessel disease in the left anterior descending artery (34 with old myocardial infarction and 7 with effort angina pectoris). Left ventricular area was divided into 6 segments, and global and regional left ventricular blood volume curves were obtained. Delayed end-systole was the most common in the apex (41%), followed by the upper septum (37%) and lower septum (10%). PSS resulting from delayed end-systole was seen in 36 areas. PSS/end-diastolic volume (EDV) and PSS/systolic volume (SV) were obtained by adjusting end-diastolic and stroke counts, respectively. Thallium-201 myocardial SPECT images were divided into 5 segments to obtain defect score (DS) for visual Tl uptake. Both PSS/EDV and PSS/SV were greater in association with more delayed end-systole, greater DS, and lower reginal ejection fraction. Areas showing greater PSS were associated with less myocardial viability, as observed on Tl myocardial SPECT images. Thus, PSS seemed to reflect the degree of myocardial necrosis within the region of interest. (N.K.)

Regional myocardial perfusion assessed by N-13 labeled ammonia and positron emission computerized axial tomography

International Nuclear Information System (INIS)

Schelbert, H.R.; Phelps, M.E.; Hoffman, E.J.; Huang, S.C.; Selin, C.E.; Kuhl, D.E.

1978-01-01

The usefulness of 13 NH 3 as an indicator of regional myocardial perfusion suitable for positron emission computerized axial tomography (PCT) has been suggested. However, the relationship between myocardial blood flow and uptake of 13 NH 3 has not been examined quantitatively. It was therefore the purpose of the current investigation to quantitate the relationship of myocardial 13 NH 3 tissue concentration to myocardial blood flow and to examine its suitability for PCT imaging. Twelve open chest dogs were studied. In 8 of the dogs 25 imaging procedures with 13 NH 3 and PCT were performed. In the remaining four dogs the relationship between flow and myocardial 13 NH 3 tissue concentration was assessed by in vitro techniques. The PCT technique provided high quality cross-sectional images of the distribution of 13 NH 3 in left ventricular myocardium. No significant redistribution of 13 NH 3 in myocardium occurred with time. Alterations in regional myocardial blood flow resulted in changes of the regional distribution of 13 NH 3 that were readily appreciated on the PCT images

Central hemodynamics and left-ventricural contractility in patients with chronic obstructive pulmonary diseases and stable pulmonary hypertension: a radionuclide study

International Nuclear Information System (INIS)

Paleev, N.R.; Malov, G.A.; Cherejskaya, N.K.; Oblovatskaya, O.G.; Tsar'kova, L.N.; Zil'berman, E.Eh.; Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Serdechno-Sosudistoj Khirurgii)

1987-01-01

Systemic, central and intracardiac hemodynamics and left-ventricular contractility were studied radiocardiographically and radioventriculographically in 22 patients with stable pulmanory hypertension, developing in the presence of chronic obstructive pulmanory diseases. A tendency to increased circulating blood volume, significantly elevated end diastolic and end systolic indices, reduced total ejection fraction, and a tendency to decreased segmental ejection fractions were demonstrated. A significant reduction of the speed and percetage of left-ventricular myocardial circular fibre contraction is another evedence of incompetent left-ventricular contractility, in addition to the reduced ejection fraction

Effect of myocardial viability in the infarct area on regional left ventricular function

International Nuclear Information System (INIS)

Ishii, Toshihiko; Watanabe, Takeshi; Usui, Mikio; Nagai, Yoshikazu

1990-01-01

This study explored the relationship between global left ventricular ejection fraction (LVEF), regional LVEF of infarct myocardium, and the viability of the myocardium due to the development of collaterals in the infarct area. Each was evaluated by exercise thallium-201 myocardial SPECT, multigated blood pool scintigraphy and coronary angiography. A total of 68 patients with old anteroseptal myocardial infarction and 23 normal persons were studied. The patients were found to have septal defect on exercise thallium images. According to the appearance of redistribution (RD) on delayed images, the patients were classified as having positive RD (n=42, 62%) or negative RD (n=26, 38%). The global LVEF was compared with regional LVEF of the basal, middle and apical areas within septum, as calculated by multigated blood pool scintigraphy. There was no significant difference in global LVEF between the groups of positive and negative RD patients. However, regional LVEF of the basal and middle areas was significantly larger in the group of positive RD than the group of negative RD. Collaterals were significantly observed in the group of positive RD, as compared with the group of negative RD (53% vs 25%). It was more frequent in cases of higher degree of stenosis. In the group of negative RD, none of the patients had collaterals when coronary stenosis was 90% or less. Redistribution may reflect myocardial viability. Myocardial viability within the infarct area had favorable influences on the regional left ventricular function. Therefore, not only global but also regional left ventricular function is necessary for better understanding of pathophysiology of myocardial infarction.(N.K.)

Dobutamine cine magnetic resonance imaging after myocardial infarction

International Nuclear Information System (INIS)

Giovagnoni, A.; Ligabue, G.; Romagnoli, R.; Reggio Emilia Univ., Reggio Emilia; Rossi, R.; Muia, N.; Modena, M.G.; Reggio Emilia Univ.

1999-01-01

Dobutamine Cine MRI is a new diagnostic imaging technique in the pretreatment (revascularization) assessment of myocardial infarction patients. In this issue are reported the result of a comparative study of the diagnostic yield of dobutamine Cine MRI with that of stress echocardiography in the assessment of viable myocardium. A new method for analysis of Cine MR images, employing digital subtraction, aimed at decreasing subjectivity in the quantitative assessment of myocardial wall thickening. Twenty-six patients (21 men and 5 women) with a history of myocardial infarction who were scheduled for revascularization were submitted to stress echocardiography and dobutamine Cine MRI to evaluate contractile recovery of the segments considered akinetic or hypo kinetic at baseline echocardiography. Dobutamine was administered in growing doses (5, 10, 15γ/kg/min). 16 segments of the left ventricle in each patient were considered. In the 416 segments studied, it was found that 307 normo kinetic, 64 scarred and 45 viable segments with stress echocardiography, versus 302 normo kinetic, 83 scarred and 31 viable segments with dobutamine MRI. Three months after revascularization 15 patients were examined to check contractile recovery of the segments considered as viable. Echocardiography had 79% sensitivity and 97% specificity, while Cine MRI had 96% and 86%, respectively. In patients with anteroseptal wall myocardial infarction stress echocardiography had 75% sensitivity and 97% specificity. Echocardiography permits to distinguish viable myocardium and scarred myocardial tissue with good sensitivity and specificity, but Cine MRI performs better. Cine MRI has much higher sensitivity than stress echocardiography and thus makes the technique of choice to evaluate viable myocardium in these sites. The digital subtraction technique is as accurate as manual measurements, but reduces the error rate and permits quicker evaluation, particularly in subendocardial thickening [it

Vitamin D Levels and myocardial function in preterm infants

LENUS (Irish Health Repository)

Armstrong, K

2013-08-20

Bakground Low Vitamin D levels have been linked to cardiac failure in the adults and children. Tissue Doppler Imaging (TDI) is evolving as a superior measure of subtle changes in myocardial contractility in preterm infants. We aimed to correlate Vitamin D levels at birth with TDI measures of systolic and diastolic function. \\r\

Cadmium translocation by contractile roots differs from that in regular, non-contractile roots.

Science.gov (United States)

Lux, Alexander; Lackovič, Andrej; Van Staden, Johannes; Lišková, Desana; Kohanová, Jana; Martinka, Michal

2015-06-01

Contractile roots are known and studied mainly in connection with the process of shrinkage of their basal parts, which acts to pull the shoot of the plant deeper into the ground. Previous studies have shown that the specific structure of these roots results in more intensive water uptake at the base, which is in contrast to regular root types. The purpose of this study was to find out whether the basal parts of contractile roots are also more active in translocation of cadmium to the shoot. Plants of the South African ornamental species Tritonia gladiolaris were cultivated in vitro for 2 months, at which point they possessed well-developed contractile roots. They were then transferred to Petri dishes with horizontally separated compartments of agar containing 50 µmol Cd(NO3)2 in the region of the root base or the root apex. Seedlings of 4-d-old maize (Zea mays) plants, which do not possess contractile roots, were also transferred to similar Petri dishes. The concentrations of Cd in the leaves of the plants were compared after 10 d of cultivation. Anatomical analyses of Tritonia roots were performed using appropriately stained freehand cross-sections. The process of contraction required specific anatomical adaptation of the root base in Tritonia, with less lignified and less suberized tissues in comparison with the subapical part of the root. These unusual developmental characteristics were accompanied by more intensive translocation of Cd ions from the basal part of contractile roots to the leaves than from the apical-subapical root parts. The opposite effects were seen in the non-contractile roots of maize, with higher uptake and transport by the apical parts of the root and lower uptake and transport by the basal part. The specific characteristics of contractile roots may have a significant impact on the uptake of ions, including toxic metals from the soil surface layers. This may be important for plant nutrition, for example in the uptake of nutrients from

Sex differences and the effects of ovariectomy on the β-adrenergic contractile response

Science.gov (United States)

McIntosh, Victoria J.; Chandrasekera, P. Charukeshi

2011-01-01

The presence of sex differences in myocardial β-adrenergic responsiveness is controversial, and limited studies have addressed the mechanism underlying these differences. Studies were performed using isolated perfused hearts from male, intact female and ovariectomized female mice to investigate sex differences and the effects of ovarian hormone withdrawal on β-adrenergic receptor function. Female hearts exhibited blunted contractile responses to the β-adrenergic receptor agonist isoproterenol (ISO) compared with males but not ovariectomized females. There were no sex differences in β1-adrenergic receptor gene or protein expression. To investigate the role of adenylyl cyclase, phosphodiesterase, and the cAMP-signaling cascade in generating sex differences in the β-adrenergic contractile response, dose-response studies were performed in isolated perfused male and female hearts using forskolin, 3-isobutyl-1-methylxanthine (IBMX), and 8-(4-chlorophenylthio)adenosine 3′,5′-cyclic monophosphate (CPT-cAMP). Males showed a modestly enhanced contractile response to forskolin at 300 nM and 5 μM compared with females, but there were no sex differences in the response to IBMX or CPT-cAMP. The role of the A1 adenosine receptor (A1AR) in antagonizing the β-adrenergic contractile response was investigated using both the A1AR agonist 2-chloro-N6-cyclopentyl-adenosine and A1AR knockout (KO) mice. Intact females showed an enhanced A1AR anti-adrenergic effect compared with males and ovariectomized females. The β-adrenergic contractile response was potentiated in both male and female A1ARKO hearts, with sex differences no longer present above 1 nM ISO. The β-adrenergic contractile response is greater in male hearts than females, and minor differences in the action of adenylyl cyclase or the A1AR may contribute to these sex differences. PMID:21685268

Na(+)/Ca(2+) exchanger inhibition exerts a positive inotropic effect in the rat heart, but fails to influence the contractility of the rabbit heart.

Science.gov (United States)

Farkas, A S; Acsai, K; Nagy, N; Tóth, A; Fülöp, F; Seprényi, G; Birinyi, P; Nánási, P P; Forster, T; Csanády, M; Papp, J G; Varró, A; Farkas, A

2008-05-01

The Na(+)/Ca(2+) exchanger (NCX) may play a key role in myocardial contractility. The operation of the NCX is affected by the action potential (AP) configuration and the intracellular Na(+) concentration. This study examined the effect of selective NCX inhibition by 0.1, 0.3 and 1.0 microM SEA0400 on the myocardial contractility in the setting of different AP configurations and different intracellular Na(+) concentrations in rabbit and rat hearts. The concentration-dependent effects of SEA0400 on I(Na/Ca) were studied in rat and rabbit ventricular cardiomyocytes using a patch clamp technique. Starling curves were constructed for isolated, Langendorff-perfused rat and rabbit hearts. The cardiac sarcolemmal NCX protein densities of both species were compared by immunohistochemistry. SEA0400 inhibited I(Na/Ca) with similar efficacy in the two species; there was no difference between the inhibitions of the forward or reverse mode of the NCX in either species. SEA0400 increased the systolic and the developed pressure in the rat heart in a concentration-dependent manner, for example, 1.0 microM SEA0400 increased the maximum systolic pressures by 12% relative to the control, whereas it failed to alter the contractility in the rabbit heart. No interspecies difference was found in the cardiac sarcolemmal NCX protein densities. NCX inhibition exerted a positive inotropic effect in the rat heart, but it did not influence the contractility of the rabbit heart. This implies that the AP configuration and the intracellular Na(+) concentration may play an important role in the contractility response to NCX inhibition.

Assessment of Myocardial Contractile Function Using Global and Segmental Circumferential Strain following Intracoronary Stem Cell Infusion after Myocardial Infarction: MRI Feature Tracking Feasibility Study

International Nuclear Information System (INIS)

Bhatti, Sabha; Al-Khalidi, Hussein; Hor, Kan; Hakeem, Abdul; Taylor, Michael; Quyyumi, Arshed A.; Oshinski, John; Pecora, Andrew L.; Kereiakes, Dean; Chung, Eugene; Pedrizzetti, Gianni; Miszalski-Jamka, Tomasz; Mazur, Wojciech

2012-01-01

Background. Magnetic resonance imaging (MRI) strain analysis is a sensitive method to assess myocardial function. Our objective was to define the feasibility of MRI circumferential strain (ε cc ) analysis in assessing subtle changes in myocardial function following stem cell therapy. Methods and Results. Patients in the Amorcyte Phase I trial were randomly assigned to treatment with either autologous bone-marrow-derived stem cells infused into the infarct-related artery 5 to 11 days following primary PCI or control. MRI studies were obtained at baseline, 3, and 6 months. ε cc was measured in the short axis views at the base, mid and apical slices of the left ventricle (LV) for each patient (13 treatments and 10 controls). Mid-anterior LV ε cc improved between baseline −18.5 ± 8.6 and 3 months −22.6 ± 7.0, P = 0.03. There were no significant changes in ε cc at 3 months and 6 months compared to baseline for other segments. There was excellent intraobserver and interobserver agreement for basal and mid circumferential strain. Conclusion. MRI segmental strain analysis is feasible in assessment of regional myocardial function following cell therapy with excellent intra- and inter-observer variability's. Using this method, a modest interval change in segmental ε cc was detected in treatment group

Análise comparativa dos efeitos do diazepam, midazolam, propofol e etomidato na contratilidade miocárdica e no fluxo coronariano: estudo em corações isolados de ratos Effects of diazepam, midazolam, propofol and etomidate in myocardial contractility and coronary blood flow: comparative analysis in isolated rat's hearts

Directory of Open Access Journals (Sweden)

Carlos Geraldo Sobral de Medeiros

2004-06-01

Full Text Available OBJETIVO: Avaliar o efeito, na contratilidade miocárdica e no fluxo coronariano, de drogas comumente utilizadas na prática clínica (diazepam, midazolam, propofol e etomidato. MÉTODO: Foram estudados 50 corações isolados de ratos Wistar divididos em cinco grupos de dez, em preparação de Langendorff com líquido de perfusão de Krebs-Henseleit (K-H, mantendo-se constantes a pressão de perfusão (90 centímetros de água e a temperatura (37° + 0,5 graus Celsius. Com exceção do Grupo I (Controle, foram feitas infusões únicas, em um minuto, de diazepam (50 microgramas - Grupo II; midazolam (25 microgramas - Grupo III; propofol (25 e 50 microgramas - Grupo IV e etomidato (25 microgramas - Grupo V. Cada dose foi diluída e administrada em 0,1 mililitro de K-H, mantendo-se o fluxo e a pressão de perfusão coronarianos do sistema, durante sua infusão. Aferiu-se a freqüência cardíaca em batimentos por minuto (BPM, a tensão miocárdica em gramas (g, e o fluxo coronariano em mililitros por minuto (ml/min em 1, 3, 5, 10, 15, 20, 25 e 30 minutos; a contratilidade miocárdica foi avaliada pelo cálculo da primeira derivada tensão/tempo (dT/dtmax, naquelas marcas. RESULTADOS: A freqüência cardíaca apresentou variações nos Grupos I, III e IV. Em relação à tensão miocárdica, apenas o Grupo I não sofreu declínio; o fluxo coronariano, exceto no Grupo IV, apresentou variações para menos, ao longo do estudo; a contratilidade miocárdica decresceu em todos os grupos estudados, exceto no Grupo I. CONCLUSÃO: As drogas ensaiadas diminuíram a contratilidade miocárdica (p0,05.OBJECTIVE: The effects on myocardial contractility (dT/dtmax and coronary blood flow (CBF of common drugs used in clinical practice (diazepam, midazolam, propofol and etomidate were studied. METHOD: Fifty Wistar rat's hearts were divided into five groups of ten, and perfused by Langendorff method with Krebs-Henseleit solution (K-H, with the perfusion pressure

Association between left ventricular regional sympathetic denervation and mechanical dyssynchrony in phase analysis: a cardiac CZT study

International Nuclear Information System (INIS)

Gimelli, Alessia; Genovesi, Dario; Giorgetti, Assuero; Kusch, Annette; Liga, Riccardo; Marzullo, Paolo

2014-01-01

To evaluate the relationships among myocardial sympathetic innervation, perfusion and mechanical synchronicity assessed with cardiac cadmium-zinc-telluride (CZT) scintigraphy. A group of 29 patients underwent an evaluation of myocardial perfusion with 99m Tc-tetrofosmin CZT scintigraphy and adrenergic innervation with 123 I-metaiodobenzylguanidine (MIBG) CZT scintigraphy. The summed rest score (SRS), motion score (SMS) and thickening score (STS), as well as the summed 123 I-MIBG defect score (SS-MIBG), were determined. Regional tracer uptake for both 99m Tc-tetrofosmin and 123 I-MIBG was also calculated. Finally, the presence of significant myocardial mechanical dyssynchrony was evaluated in phase analysis on gated CZT images and the region of latest mechanical activation identified. Significant mechanical dyssynchrony was present in 17 patients (59 %) and associated with higher SRS (P = 0.030), SMS (P 123 I-MIBG uptake (P = 0.012) that overwhelmed the effect of depressed regional perfusion. Left ventricular mechanical dyssynchrony is associated with greater depression in contractile function and greater impairments in regional myocardial perfusion and sympathetic activity. In patients with dyssynchrony, the region of latest mechanical activation is characterized by a significantly altered adrenergic tone. (orig.)

[Speckle tracking--a new ultrasound tool for the assessment of fetal myocardial function].

Science.gov (United States)

Willruth, A; Geipel, A; Merz, W; Gembruch, U

2012-06-01

Speckle tracking is a new ultrasound tool to assess 2D ventricular global and segmental myocardial velocity and deformation (strain, strain rate). Multiple factors such as fetal motion, high heart rates, low blood pressure, small size of the heart, physiological cardiac translation, filling and maturational changes of myocardium, polyhydramnion, maternal obesity and aortic pulsation can degrade the image quality and result in artifacts and measurement errors which may have an impact on the final analysis. Therefore deformation indices such as strain and strain rate offer a quantitative technique for the estimation of global and segmental myocardial function and contractility. At present longitudinal peak systolic strain is the most commonly applied deformation parameter used to analyse segmental and global myocardial contractility in adults. When obtained using Doppler methods, these measurements are angle dependent, whereas speckle tracking techniques overcome the limitations of Doppler echocardiography which is a particular advantage in foetal echocardiography. Nevertheless, the time and training necessary to acquire high-quality video clips limit the implementation of speckle tracking into clinical routine. It is not yet clear whether this new technique will identify subclinical myocardial impairment earlier than with current techniques or allow for better discrimination between healthy fetuses and fetuses with congenital heart disease. The clinical use of speckle tracking will have to be demonstrated in larger groups of complicated pregnancies. © Georg Thieme Verlag KG Stuttgart · New York.

Formation and breakdown of adenosine in the heart : investigations on myocardial purine metabolismen

NARCIS (Netherlands)

P.W. Achterberg (Peter)

1986-01-01

textabstractAdenosine, a strong coronary vasodilator, is a breakdown product of the myocardial high-energy phosphate ATP. ATP serves as the direct energy source for contraction of the heart. Chapter 1 of this thesis gives a general introduction on contractility dependent ATP-breakdown, the

Exposure to low mercury concentration in vivo impairs myocardial contractile function

International Nuclear Information System (INIS)

Furieri, Lorena Barros; Fioresi, Mirian; Junior, Rogerio Faustino Ribeiro; Bartolome, Maria Visitacion; Fernandes, Aurelia Araujo; Cachofeiro, Victoria; Lahera, Vicente; Salaices, Mercedes; Stefanon, Ivanita; Vassallo, Dalton Valentim

2011-01-01

Increased cardiovascular risk after mercury exposure has been described but cardiac effects resulting from controlled chronic treatment are not yet well explored. We analyzed the effects of chronic exposure to low mercury concentrations on hemodynamic and ventricular function of isolated hearts. Wistar rats were treated with HgCl 2 (1st dose 4.6 μg/kg, subsequent dose 0.07 μg/kg/day, im, 30 days) or vehicle. Mercury treatment did not affect blood pressure (BP) nor produced cardiac hypertrophy or changes of myocyte morphometry and collagen content. This treatment: 1) in vivo increased left ventricle end diastolic pressure (LVEDP) without changing left ventricular systolic pressure (LVSP) and heart rate; 2) in isolated hearts reduced LV isovolumic systolic pressure and time derivatives, and β-adrenergic response; 3) increased myosin ATPase activity; 4) reduced Na + -K + ATPase (NKA) activity; 5) reduced protein expression of SERCA and phosphorylated phospholamban on serine 16 while phospholamban expression increased; as a consequence SERCA/phospholamban ratio reduced; 6) reduced sodium/calcium exchanger (NCX) protein expression and α-1 isoform of NKA, whereas α-2 isoform of NKA did not change. Chronic exposure for 30 days to low concentrations of mercury does not change BP, heart rate or LVSP but produces small but significant increase of LVEDP. However, in isolated hearts mercury treatment promoted contractility dysfunction as a result of the decreased NKA activity, reduction of NCX and SERCA and increased PLB protein expression. These findings offer further evidence that mercury chronic exposure, even at small concentrations, is an environmental risk factor affecting heart function. - Highlights: → Unchanges blood pressure, heart rate, systolic pressure. → Increases end diastolic pressure. → Promotes cardiac contractility dysfunction. → Decreases NKA activity, NCX and SERCA, increases PLB protein expression. → Small concentrations constitutes

Genetically determined differences in the resistance to myocardial infarction in Wistar and August rats.

Science.gov (United States)

Belkina, L M; Saltykova, V A; Pshennikova, M G

2001-06-01

In intact August rats, the cardiac contractile function at rest was by 76% higher than in Wistar rats, while their hearts, both intact and after acute myocardial infarction, were more resistant to isometric load than the hearts of Wistar rats. Postinfarction mortality in August rats was 18% vs. 70% in Wistar rats. Adrenoreactivity of the myocardium in August rats was decreased compared to that in Wistar rats. These peculiarities can determine high resistance of August rats to myocardial infarction.

Assessment of relationship between regional perfusion and ventricular function in patients with severely depressed ejection fraction

International Nuclear Information System (INIS)

Teresinska, A.; Konieczna, S.; Szumilak, B.; Gosiewska-Marcinkowska, E.; Potocka, J.

1998-01-01

Patients with low ventricular (LV) ejection fraction (EF) and with regional or global LV dysfunction, considered for myocardial revascularization, are often submitted to myocardial perfusion study to ptrove perfusion preserved and to approximate viability. The aim of this work is to evaluate, to what extent SPECT with Tc-99m-MIBI (SPECT-MIBI) additionally differentiatesa and enlarges the information on LV contractility achieved from radioisotopic ventriculography (RNV). Seventy-three patients with EF=0.11-0.35 (mean: 0.26 ± 0.06, calculated from RNV) were studied. Planar gated RNV and SPECT-MIBI were performed within 2 months (mean: 15 ± 14 days). RNV, after in vivo red cells labeling with Tc-99m, was recorded in rest in LAO45 and RAO30 views. Global EF and contractility of 5 regions (anterior, posterior, lateral walls, septum and apex) were evaluated. Assessment was performed by means of LV in 'cine' mode,m ED and ES outlines and amplitude-phase images. Regional contractility abnormalities were classified as dyskinesis, akinesis and hypokinesis. SPECT-MIBI was performed in rest and stress. Perfusion abnormalities in 5 above mentioned regions was classified as large (more intense than 50% of myocardial maximum) or small persistent defects (DEFpers), large or small partially reversible defects (DEFpart-rev), large or small completely reversible defects (DEFrev). Hypokinesis was detected in 23-35 regions (65%) , dyskinesis - in 63 (17%), akinesis - in 37 (10%), normokinesis - in 27 (7%). In dyskinetic regions, there existed large DEFpers (79%) or large DEFpart-rev (21%). In akinetic regions, there also existed large DEFpers (68%) or large DEFpart-rev (32%). In hypokinetic regions, there were no perfusion defects (31% of regions), small DEFpers, DEFrev and DEFpart-rev (42%) and also large DEFpers (27%). In most of normokinetic regions, different types of perfusion defects were observed (large DEFpers existed in 26% of regions). In summary: In dyskinetic and akinetic

Follow-up of regional myocardial T2 relaxation times in patients with myocardial infarction evaluated with magnetic resonance imaging

International Nuclear Information System (INIS)

Krauss, X.H.; Wall, E. van der; Laarse, A. van der; Dijkman, P.R.M. van; Bruschke, A.V.G.; Doornbos, J.; Roos, A. de; Voorthuisen, A.E. van

1990-01-01

Multi-echo spin-echo cardiac magnetic resonance imaging studies (echo times 30, 60, 90 and 120 ms) were performed in 19 patients with a 7-14-day (mean 10) old myocardial infarction and were repeated in 13 patients 4-7 months (mean 6) later. Also, 10 normal subjects were studied with magnetic resonance imaging. T2 relaxation times of certain left ventricular segments were calculated from the signal intensities at echo times of 30 and 90 ms. Compared to normal individuals, the mean T2 values on the early magnetic resonance images of the patients with inferior infarction showed significantly prolonged T2 times in the inferiorly localized segments, while on the follow-up magnetic resonance images the T2 times had almost returned to the normal range. Also the patients with anterior infarction showed significantly prolonged T2 times in the anteriorly localized segments on the early nuclear magnetic resonance images, but the T2 times remained prolonged at the follow-up magnetic resonance images. For every patient a myocardial damage score was determined, which was defined as the sum of the segmental T2 values in the patients minus the upper limit of normal T2 values obtained from the normal volunteers (= mean normal+2SD). The damage score on both the early and late magnetic resonance imaging study correlated well with the infarction size determined by myocardial enzyme release. Only the patients with an inferior infarction showed a significant decrease in damage score at follow-up magnetic resonance imaging. It is concluded that the regional T2 relaxation times are increased in infarcted myocardial regions and may remain prolonged for at least up to 7 months after the acute event, particularly in patients with an anterior infarction. These findings demonstrate the clinical potential of T2-weighted magnetic resonance imaging studies for detecting myocardial infarction, and estimating infarct size for an extended period after acute myocardial infarction. (author). 29 refs

Myocardial perfusion and left ventricular function early after successful PTCA in 1-vessel coronary artery diseases

International Nuclear Information System (INIS)

Hoffmeister, H.M.; Kaiser, W.; Hanke, H.; Mueller-Schauenburg, W.; Karsch, K.R.; Seipel, L.

1994-01-01

Myocardial perfusion ( 201 Tl-ECT) and contractile function ( 99m Tc-ventriculography) were studied during exercise and rest 3 to 6 days after PTCA in 20 patients (11 with stable and 9 with unstable angina pectoris). All patients had single vessel disease and no previous myocardial infarction. During exercise after PTCA the ejection fraction increased for 3 to 5% and no regional wall motion abnormalities, ST-segment depression or perfusion defects occurred (with exception in one patient with very early restenosis). Therefore, perfusion and wall motion were completely normalized at test and during exercise within days after technically successful PTCA even in patients with previously unstable angina pectoris. Pathological stress test results after this time should thus be attributed to other causes e.g. early restenosis, multivessel disease, false positive tests) and are not due to the specific situation early after PTCA. (orig.) [de

Comparative assessment of beneficial effects of intracoronary and systemic thrombolytic therapy of acute myocardial infarction

International Nuclear Information System (INIS)

Khalfen, Eh.Sh.; Shtern, S.V.; Shvarts, I.L.; Bezrukova, G.A.; Zolotarev, V.A.; Rakovskij, M.E.

1989-01-01

Comparative study was made on clinical efficiency of introcoronary thrombolytic therapy with streptokinase and systematic thrombolytic therapy with streptodekase for 189 patients with transmural myocardial infarction. Intravenous digital subtraction ventriculography was conducted to obtain indices of hemodynamics and contractility of the left venricle

High fat diet-induced glucose intolerance impairs myocardial function, but not myocardial perfusion during hyperaemia: a pilot study

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van den Brom Charissa E

2012-06-01

Full Text Available Abstract Background Glucose intolerance is a major health problem and is associated with increased risk of progression to type 2 diabetes mellitus and cardiovascular disease. However, whether glucose intolerance is related to impaired myocardial perfusion is not known. The purpose of the present study was to study the effect of diet-induced glucose intolerance on myocardial function and perfusion during baseline and pharmacological induced hyperaemia. Methods Male Wistar rats were randomly exposed to a high fat diet (HFD or control diet (CD (n = 8 per group. After 4 weeks, rats underwent an oral glucose tolerance test. Subsequently, rats underwent (contrast echocardiography to determine myocardial function and perfusion during baseline and dipyridamole-induced hyperaemia (20 mg/kg for 10 min. Results Four weeks of HFD feeding resulted in glucose intolerance compared to CD-feeding. Contractile function as represented by fractional shortening was not altered in HFD-fed rats compared to CD-fed rats under baseline conditions. However, dipyridamole increased fractional shortening in CD-fed rats, but not in HFD-fed rats. Basal myocardial perfusion, as measured by estimate of perfusion, was similar in CD- and HFD-fed rats, whereas dipyridamole increased estimate of perfusion in CD-fed rats, but not in HFD-fed rats. However, flow reserve was not different between CD- and HFD-fed rats. Conclusions Diet-induced glucose intolerance is associated with impaired myocardial function during conditions of hyperaemia, but myocardial perfusion is maintained. These findings may result in new insights into the effect of glucose intolerance on myocardial function and perfusion during hyperaemia.

Cardiac-Specific Overexpression of Catalase Attenuates Lipopolysaccharide-Induced Myocardial Contractile Dysfunction: Role of Autophagy

OpenAIRE

Turdi, Subat; Han, Xuefeng; Huff, Anna F.; Roe, Nathan D.; Hu, Nan; Gao, Feng; Ren, Jun

2012-01-01

Lipopolysaccharide (LPS) from Gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complication in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged ...

Global and Regional Left Ventricular Contractile Impairment In Patients With Wolff-Parkinson-White Syndrome

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Sony Jacob

2009-07-01

Full Text Available Background: To assess regional systolic function and global contractile function in patients with WPW Syndrome.Method: Eleven cases with manifest Wolff-Parkinson-White (WPW syndrome in sinus rhythm were compared to 11 age matched controls. 2D strain analysis was performed and peak segmental radial strain (pRS values obtained from basal ventricular parasternal short-axis images (70 ± 5 frames/sec using a dedicated software package. Heterogeneity of radial strain pattern in six circumferential basal left ventricular segments was measured in terms of standard deviations of peak RS (SDpRS or range (difference between maximum and minimum peak RS i.e. RangepRS. Spectral Doppler (continuous wave measurements were acquired through the left ventricular outflow tract to determine Pre Ejection Period (PEP, Left Ventricular Ejection Time (LVET and measures of left ventricular systolic performance. Results: LV segmental radial strain was profoundly heterogeneous in WPW cases in contrast to fairly homogenous strain pattern in normal subjects. Wide SDpRS values 17.5 ± 8.9 vs 3.3 ± 1.4, p<0.001 and RangepRS 42.7 ± 20.8 vs.8.5 ± 3.6 , p<0.001 were observed among WPW and healthy subjects respectively. PEP (132.4 ± 14.7 vs 4.7 ± 0.5ms, p<0.001 and corrected PEP (76.1 ± 8.0 vs 2.7 ± 0.4ms, p<0.001 were significantly longer in WPW patients compared to controls. The PEP/LVET ratio was also significantly greater in WPW cohort (0.49 ± 0.04 vs. 0.28 ± 0.05, p <0.001 suggesting global systolic dysfunction. Conclusion: Patients with manifest preexcitation (predominantly those with right-sided pathways have regional and global contractile dysfunction resulting from aberrant impulse propagation inherent to the preexcited state.

Ventricular performance and Na+-K+ ATPase activity are reduced early and late after myocardial infarction in rats

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I. Stefanon

2009-10-01

Full Text Available Myocardial infarction leads to compensatory ventricular remodeling. Disturbances in myocardial contractility depend on the active transport of Ca2+ and Na+, which are regulated by Na+-K+ ATPase. Inappropriate regulation of Na+-K+ ATPase activity leads to excessive loss of K+ and gain of Na+ by the cell. We determined the participation of Na+-K+ ATPase in ventricular performance early and late after myocardial infarction. Wistar rats (8-10 per group underwent left coronary artery ligation (infarcted, Inf or sham-operation (Sham. Ventricular performance was measured at 3 and 30 days after surgery using the Langendorff technique. Left ventricular systolic pressure was obtained under different ventricular diastolic pressures and increased extracellular Ca2+ concentrations (Ca2+e and after low and high ouabain concentrations. The baseline coronary perfusion pressure increased 3 days after myocardial infarction and normalized by 30 days (Sham 3 = 88 ± 6; Inf 3 = 130 ± 9; Inf 30 = 92 ± 7 mmHg; P < 0.05. The inotropic response to Ca2+e and ouabain was reduced at 3 and 30 days after myocardial infarction (Ca2+ = 1.25 mM; Sham 3 = 70 ± 3; Inf 3 = 45 ± 2; Inf 30 = 29 ± 3 mmHg; P < 0.05, while the Frank-Starling mechanism was preserved. At 3 and 30 days after myocardial infarction, ventricular Na+-K+ ATPase activity and contractility were reduced. This Na+-K+ ATPase hypoactivity may modify the Na+, K+ and Ca2+ transport across the sarcolemma resulting in ventricular dysfunction.

Pneumopyopericardium mimicking an inferior ST elevation myocardial infarction with regional electrocardiogram changes: a case report.

Science.gov (United States)

Ratnayake, Eranda Chamara; Premaratne, Sandamali; Lokunarangoda, Niroshan; Fernando, Sanduni; Fernando, Nilanthi; Ponnamperuma, Chandrike; Santharaj, W Samuel

2015-04-30

Pneumopyopericardium is a rare disease with poor prognosis. The usual presentation is with fever, shortness of breath and haemodynamic compromise. The Electrocardiogram changes associated with this disease entity would be similar to pericarditis such as concave shaped ST elevations in all leads with PR sagging. Pneumopyopericardium mimicking an acute ST Elevation Myocardial Infarction, with regional Electrocardiogram changes has hitherto not been described in world literature. We describe the case of a 48 year old native Sri Lankan man, presenting with chest pain and Electrocardiogram changes compatible with an Acute ST Elevation Myocardial Infarction, subsequently found to have Pneumopyopericardium secondary to an oesophageal tear. Retrospective history revealed repetitive vomiting due to heavy alcohol consumption, prior to presentation. It unfortunately led to a fatal outcome. Pneumopyopericardium may mimic an acute ST elevation myocardial infarction with associated regional Electrocardiogram changes. A high degree of suspicion should be maintained and an adequate history should always be obtained prior to any intervention in all ST Elevation Myocardial Infarction patients.

Regional sympathetic denervation after myocardial infarction in humans detected noninvasively using I-123-metaiodobenzylguanidine

Energy Technology Data Exchange (ETDEWEB)

Stanton, M.S.; Tuli, M.M.; Radtke, N.L.; Heger, J.J.; Miles, W.M.; Mock, B.H.; Burt, R.W.; Wellman, H.N.; Zipes, D.P. (Indiana Univ. School of Medicine, IN (USA))

1989-11-15

Transmural myocardial infarction in dogs produces denervation of sympathetic nerves in viable myocardium apical to the infarct that may be arrhythmogenic. It is unknown whether sympathetic denervation occurs in humans. The purpose of this study was to use iodine-123-metaiodobenzylguanidine (MIBG), a radiolabeled guanethidine analog that is actively taken up by sympathetic nerve terminals, to image noninvasively the cardiac sympathetic nerves in patients with and without ventricular arrhythmias after myocardial infarction. Results showed that 10 of 12 patients with spontaneous ventricular tachyarrhythmias after myocardial infarction exhibited regions of thallium-201 uptake indicating viable perfused myocardium, with no MIBG uptake. Such a finding is consistent with sympathetic denervation. One patient had frequent episodes of nonsustained ventricular tachycardia induced at exercise testing that was eliminated by beta-adrenoceptor blockade. Eleven of the 12 patients had ventricular tachycardia induced at electrophysiologic study and metoprolol never prevented induction. Sympathetic denervation was also detected in two of seven postinfarction patients without ventricular arrhythmias. Normal control subjects had no regions lacking MIBG uptake. This study provides evidence that regional sympathetic denervation occurs in humans after myocardial infarction and can be detected noninvasively by comparing MIBG and thallium-201 images. Although the presence of sympathetic denervation may be related to the onset of spontaneous ventricular tachyarrhythmias in some patients, it does not appear to be related to sustained ventricular tachycardia induced at electrophysiologic study.

Regional Myocardial Blood Volume and Flow: First-Pass MR Imaging with Polylysine-Gd-DTPA

Science.gov (United States)

Wilke, Norbert; Kroll, Keith; Merkle, Hellmut; Wang, Ying; Ishibashi, Yukata; Xu, Ya; Zhang, Jiani; Jerosch-Herold, Michael; Mühler, Andreas; Stillman, Arthur E.; Bassingthwaighte, James B.; Bache, Robert; Ugurbil, Kamil

2010-01-01

The authors investigated the utility of an intravascular magnetic resonance (MR) contrast agent, poly-L-lysine-gadolinium diethylenetriaminepentaacetic acid (DTPA), for differentiating acutely ischemic from normally perfused myocardium with first-pass MR imaging. Hypoperfused regions, identified with microspheres, on the first-pass images displayed significantly decreased signal intensities compared with normally perfused myocardium (P < .0007). Estimates of regional myocardial blood content, obtained by measuring the ratio of areas under the signal intensity-versus-time curves in tissue regions and the left ventricular chamber, averaged 0.12 mL/g ± 0.04 (n = 35), compared with a value of 0.11 mL/g ± 0.05 measured with radiolabeled albumin in the same tissue regions. To obtain MR estimates of regional myocardial blood flow, in situ calibration curves were used to transform first-pass intensity-time curves into content-time curves for analysis with a multiple-pathway, axially distributed model. Flow estimates, obtained by automated parameter optimization, averaged 1.2 mL/min/g ± 0.5 [n = 29), compared with 1.3 mL/min/g ± 0.3 obtained with tracer microspheres in the same tissue specimens at the same time. The results represent a combination of T1-weighted first-pass imaging, intravascular relaxation agents, and a spatially distributed perfusion model to obtain absolute regional myocardial blood flow and volume. PMID:7766986

Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease.

Science.gov (United States)

Kazmaier, S; Weyland, A; Buhre, W; Stephan, H; Rieke, H; Filoda, K; Sonntag, H

1998-10-01

Variation of the arterial carbon dioxide partial pressure (PaCO2) is not uncommon in anesthetic practice. However, little is known about the myocardial consequences of respiratory alkalosis and acidosis, particularly in patients with coronary artery disease. The aim of the current study was to investigate the effects of variation in PaCO2 on myocardial blood flow (MBF), metabolism, and systemic hemodynamics in patients before elective coronary artery bypass graft surgery. In 10 male anesthetized patients, measurements of MBF, myocardial contractility, metabolism, and systemic hemodynamics were made in a randomized sequence at PaCO2 levels of 30, 40, and 50 mmHg, respectively. The MBF was measured using the Kety-Schmidt technique with argon as a tracer. End-diastolic left ventricular pressure and the maximal increase of left ventricular pressure were assessed using a manometer-tipped catheter. The cardiac index significantly changed with varying PaCO2 levels (hypocapnia, - 9%; hypercapnia, 13%). This reaction was associated with inverse changes in systemic vascular resistance index levels. The MBF significantly increased by 15% during hypercapnia, whereas no change was found during hypocapnia. Myocardial oxygen and glucose uptake and the maximal increase of left ventricular pressure were not affected by varying PaCO2 levels. In anesthetized patients with coronary artery disease, short-term variations in PaCO2 have significant effects on MBF but do not influence global myocardial oxygen and glucose uptake. Changes in systemic hemodynamics associated with respiratory alkalosis and acidosis are caused by changes in systemic vascular resistance rather than by alterations in myocardial contractility.

Noninvasive evaluation of regional myocardial perfusion in 112 patients using a mobile scintillation camera and intravenous nitrogen-13 labeled ammonia

International Nuclear Information System (INIS)

Walsh, W.F.; Harper, P.V.; Resnekov, L.; Fill, H.

1976-01-01

The short half-life positron emitter 13 N, as labeled ammonia ( 13 NH 4 + ), was evaluated as a myocardial imaging agent. Regional myocardial uptake of 13 NH 4 correlated with the distribution of labeled microspheres in experimental myocardial infarction. Using intravenous 13 NH 4 + , myocardial scintigraphy was performed in 85 cardiac patients and 27 normal subjects. Ninety-five scintigrams were suitable for analysis. Eighteen of 24 normal subjects had homogeneous myocardial images; six had inhomogeneous images attributable to early technical problems. Perfusion defects were observed in the scintigrams of 82% (57/65) of patients with coronary artery disease, being most common in patients with myocardial infarction (27/28). Six sequential studies showed changes in perfusion consistent with the clinical course of each patient. Scintigraphic abnormalities were also observed in 4/6 patients with valvular heart disease. 13 NH 4 + myocardial scintigraphy is a valid and sensitive method of assessing regional myocardial perfusion and is especially useful for sequential imaging at short intervals

Magnetic resonance imaging detects significant sex differences in human myocardial strain

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Reynolds Lina M

2011-08-01

Full Text Available Abstract Background The pathophysiology responsible for the significant outcome disparities between men and women with cardiac disease is largely unknown. Further investigation into basic cardiac physiological differences between the sexes is needed. This study utilized magnetic resonance imaging (MRI-based multiparametric strain analysis to search for sex-based differences in regional myocardial contractile function. Methods End-systolic strain (circumferential, longitudinal, and radial was interpolated from MRI-based radiofrequency tissue tagging grid point displacements in each of 60 normal adult volunteers (32 females. Results The average global left ventricular (LV strain among normal female volunteers (n = 32 was significantly larger in absolute value (functionally better than in normal male volunteers (n = 28 in both the circumferential direction (Male/Female = -0.19 ± 0.02 vs. -0.21 ± 0.02; p = 0.025 and longitudinal direction (Male/Female = -0.14 ± 0.03 vs. -0.16 ± 0.02; p = 0.007. Conclusions The finding of significantly larger circumferential and longitudinal LV strain among normal female volunteers suggests that baseline contractile differences between the sexes may contribute to the well-recognized divergence in cardiovascular disease outcomes. Further work is needed in order to determine the pathologic changes that occur in LV strain between women and men with the onset of cardiovascular disease.

Myocardial infarction

International Nuclear Information System (INIS)

Ando, Jyoji; Yasuda, Hisakazu; Miyamoto, Atsushi; Kobayashi, Tsuyoshi

1980-01-01

sup(99m)Tc-pyrophosphate (PYP) scintigraphy and 201 Tl myocardial scintigraphy were utilized for the diagnoses of the presence, the region, and the extent of myocardial infarction. Exercise 201 Tl myocardial scintigrams and exercise radionuclide ventriculography were utilized for diagnosis of coronary artery lesions in angina pectoris. Radionuclide ventriculography was used to investigate effects of coronary artery lesions on cardiac function and hemodynamics. In order to select adequate treatments for myocardial infarction and estimate the prognosis, it was necessary to detect the presence, the region, and the extent of acute myocardial infarction and to investigate effects of partial infarction on hemodynamics by using radionuclide imaging. Exercise myocardial scintigraphy could be carried out noninvasively and repeatedly for diagnosis of coronal artery disease. Therefore, this method could be applied widely. It was possible to use this method as a screening test of coronary artery diseases for the diagnoses of asymptomatic patients who showed ST changes in ECG, the patients with cardiac neurosis and the patency after a reconstructive surgery of coronary artery. (Tsunoda, M.)

Positron emission tomography for the assessment of myocardial viability

International Nuclear Information System (INIS)

Schelbert, H.R.

1991-01-01

The detection of viable myocardium or ischemically injured myocardium with a reversible impairment of contractile function remains clinically important but challenging. Detection of reversible dysfunction and distinction from irreversible tissue injury by positron emission tomography is based on identification of preserved or even enhanced glucose metabolism with F-18 2-fluoro 2-deoxyglucose. Regional patterns of myocardial glucose utilization and blood flow, defined as perfusion-metabolism mismatches or matches, on positron emission tomography in patients with chronic or even acute ischemic heart disease are highly accurate in predicting the functional outcome after interventional revascularization. Compared with thallium-201 redistribution scintigraphy, positron emission tomography appears to be diagnostically more accurate, especially in patients with severely impaired left ventricular function. While larger clinical trials are needed for further confirmation, positron emission tomography has already proved clinically useful for stratifying patients with poor left ventricular function to the most appropriate therapeutic approach

Influence of intracellular acidosis on contractile function in the working rat heart

International Nuclear Information System (INIS)

Jeffrey, F.M.H.; Malloy, C.R.; Radda, G.K.

1987-01-01

The decrease in myocardial contractility during ischemia, hypoxia, and extracellular acidosis has been attributed to intracellular acidosis. Previous studies of the relationship between pH and contractile state have utilized respiratory or metabolic acidosis to alter intracellular pH. The authors developed a model in the working perfused rat heart to study the effects of intracellular acidosis with normal external pH and optimal O 2 delivery. Intracellular pH and high-energy phosphates were monitored by 31 P nuclear magnetic resonance spectroscopy. Hearts were perfused to a steady state with a medium containing 10 mM NH 4 Cl. Acidosis induced a substantial decrease in aortic flow and stroke volume which was associated with little change in peak systolic pressure. It was concluded that (1) for the same intracellular acidosis the influence on tension development was more pronounced with a combined extra- and intracellular acidosis than with an isolated intracellular acidosis, and (2) stroke volume at constant preload was impaired by intracellular acidosis even though changes in developed pressure were minimal. These observations suggest that isolated intracellular acidosis has adverse effects on diastolic compliance and/or relaxation

Modulatory effects of taurine on jejunal contractility

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Q.Y. Yao

2014-12-01

Full Text Available Taurine (2-aminoethanesulfonic acid is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

Modulatory effects of taurine on jejunal contractility

Energy Technology Data Exchange (ETDEWEB)

Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y. [Dalian Medical University, Dalian, Liaoning (China)

2014-10-14

Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca{sup 2+} dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

Modulatory effects of taurine on jejunal contractility

International Nuclear Information System (INIS)

Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y.

2014-01-01

Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca 2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism

Modulatory effects of taurine on jejunal contractility

Science.gov (United States)

Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y.

2014-01-01

Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism. PMID:25387674

Noninvasive evaluation of regional myocardial perfusion in 112 patients using a mobile scintillation camera and intravenous nitrogen-13 labeled ammonia

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Walsh, W.F.; Harper, P.V.; Resnekov, L.; Fill, H.

1976-08-01

The short half-life positron emitter /sup 13/N, as labeled ammonia (/sup 13/NH/sub 4//sup +/), was evaluated as a myocardial imaging agent. Regional myocardial uptake of /sup 13/NH/sub 4/ correlated with the distribution of labeled microspheres in experimental myocardial infarction. Using intravenous /sup 13/NH/sub 4//sup +/, myocardial scintigraphy was performed in 85 cardiac patients and 27 normal subjects. Ninety-five scintigrams were suitable for analysis. Eighteen of 24 normal subjects had homogeneous myocardial images; six had inhomogeneous images attributable to early technical problems. Perfusion defects were observed in the scintigrams of 82% (57/65) of patients with coronary artery disease, being most common in patients with myocardial infarction (27/28). Six sequential studies showed changes in perfusion consistent with the clinical course of each patient. Scintigraphic abnormalities were also observed in 4/6 patients with valvular heart disease. /sup 13/NH/sub 4//sup +/ myocardial scintigraphy is a valid and sensitive method of assessing regional myocardial perfusion and is especially useful for sequential imaging at short intervals.

Fractalkine depresses cardiomyocyte contractility.

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David Taube

Full Text Available Our laboratory reported that male mice with cardiomyocyte-selective knockout of the prostaglandin E2 EP4 receptor sub-type (EP4 KO exhibit reduced cardiac function. Gene array on left ventricles (LV showed increased fractalkine, a chemokine implicated in heart failure. We therefore hypothesized that fractalkine is regulated by PGE2 and contributes to depressed contractility via alterations in intracellular calcium.Fractalkine was measured in LV of 28-32 week old male EP4 KO and wild type controls (WT by ELISA and the effect of PGE2 on fractalkine secretion was measured in cultured neonatal cardiomyocytes and fibroblasts. The effect of fractalkine on contractility and intracellular calcium was determined in Fura-2 AM-loaded, electrical field-paced cardiomyocytes. Cardiomyocytes (AVM from male C57Bl/6 mice were treated with fractalkine and responses measured under basal conditions and after isoproterenol (Iso stimulation.LV fractalkine was increased in EP4 KO mice but surprisingly, PGE2 regulated fractalkine secretion only in fibroblasts. Fractalkine treatment of AVM decreased both the speed of contraction and relaxation under basal conditions and after Iso stimulation. Despite reducing contractility after Iso stimulation, fractalkine increased the Ca(2+ transient amplitude but decreased phosphorylation of cardiac troponin I, suggesting direct effects on the contractile machinery.Fractalkine depresses myocyte contractility by mechanisms downstream of intracellular calcium.

[Digitalization for acute myocardial infarction: haemodynamic changes in patients with heart failure at rest (author's transl)].

Science.gov (United States)

Bachour, G; Hochrein, H

1975-11-21

Haemodynamic changes after intravenous administration of 0.4 mg beta-methyldigoxin or 0.4 mg digoxin daily were measured on the first to fourth day in 42 patients in heart failure after onset of transmural myocardial infarction. Regular reduction in filling pressure and increased stroke volume while arterial blood pressure remained unaltered pointed to improved contractility. Digitalization in the first few days after infarction achieved sustained tendency towards improved haemodynamics. It is concluded that early digitalization is indicated in patients with acute myocardial infarction if there are signs of heart failure.

Myocardial temperature variation: effect on regional function and coronary flow in dogs

International Nuclear Information System (INIS)

D'Ambra, M.N.; Magrassi, P.; Lowenstein, E.; Kyo, S.; Austen, W.G.; Buckley, M.J.; LaRaia, P.J.

1987-01-01

Incremental changes in the temperature (28-42.5 0 C) of the anterior left ventricular wall in a canine, working, beating right heart bypass preparation (constant preload, afterload, and heart rate) were produced to measure the effect of regional temperature on myocardial function and blood flow. Circumferential-axis segment lengths were measured with sonomicrometry in both the temperature-varied, left-anterior descending coronary artery (LAD)-supplied myocardium and the normothermic (38 0 C) circumflex-supplied myocardium. Fast thermistors (time constant 0 C), regional systolic shortening decreased 42.2 +/- 10% at 41 0 C and increased 23.3 +/- 6% at 31 0 C. There was no significant change in coronary blood flow or distribution at the three temperatures. Pressure-length areas varied inversely with myocardial temperature. These data demonstrate that there is a reversible inverse relationship between midwall T and ventricular function when heart rate, preload, and afterload are controlled

Structural comparison of contractile nanomachines

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Sebastian Kube

2015-05-01

Full Text Available Contractile molecular machines are a common feature among bacteriophages and prokaryotes. Due to their stability and the large size, contractile-tailed bacteriophages are traditionally investigated by electron microscopic methods. Complemented by crystallographic studies, a molecular model of contraction for the T4 phage was developed. Lately, also related contractile structures like the Photorhabdus virulence cassette-like particles, the R-Type pyocins and the contractile tubule of the bacterial Type VI secretion system have been analyzed by cryo electron microscopy. Photorhabdus virulence cassette particles and R-Type pyocins are toxin complexes reminiscent of bacteriophage tails that are secreted by bacteria to kill their insect host or competing bacteria. In contrast, the Type VI secretion system is an intracellular apparatus for injection of effector proteins into bacterial and eukaryotic cells. Although it shares homology with other contractile systems, the Type VI secretion system is additionally equipped with a recycling function, which makes it suitable for multiple rounds of action. Starting from the 3D reconstructions, we compare these molecular machines structurally and functionally to their viral counterparts and summarize the current knowledge on their respective mode of action.

Energy Drinks and Myocardial Ischemia: A Review of Case Reports.

Science.gov (United States)

Lippi, Giuseppe; Cervellin, Gianfranco; Sanchis-Gomar, Fabian

2016-07-01

The use and abuse of energy drinks (EDs) is constantly increasing worldwide. We performed a systematic search in Medline, Scopus and Web of Science to identify evidence about the potential link between these beverages and myocardial ischemia. Overall, 8 case reports could be detected, all of which described a realistic association between large intake of EDs and episodes of myocardial ischemia. Interestingly, no additional triggers of myocardial ischemia other than energy drinks could be identified in the vast majority of cases. Some plausible explanations can be brought in support of this association. Most of the biological effects of EDs are seemingly mediated by a positive inotropic effect on cardiac function, which entails increase in heart rate, cardiac output and contractility, stroke volume and arterial blood pressure. Additional biological abnormalities reported after EDs intake include increased platelet aggregation, endothelial dysfunction, hyperglycemia as well as an increase in total cholesterol, triglycerides and low-density lipoprotein cholesterol. Although a causal relationship between large consumption of EDs and myocardial ischemia cannot be definitely established so far, concerns about the cardiovascular risk of excessive consumption of these beverages are seemingly justified.

Detection of regional derangements in myocardial metabolism by positron computed tomography in Duchenne's muscular dystrophy

International Nuclear Information System (INIS)

Henze, E.; Schelbert, H.R.; Perloff, J.K.; Schwaiger, M.; Phelps, M.E.

1982-01-01

Duchenne's Muscular Dystrophy is unique in genetically targeting for disease a specific region of myocardium: the postero-basal left ventricular wall. Postmortem examinations revealed focal fibrous degenerations in the postero-basal segment, while the coronary arteries were usually not affected. A predystrophic metabolic fault has been postulated for this region. This hypothesis was tested with positron computed tomography as a new means for the noninvasive study of regional myocadial perfusion and metabolism and to determine the incidence of regional and global left ventricular dysfunction and perfusion abnormalities using Thallium-201 and gated blood pool imaging. Myocardial perfusion was evaluated with N-13 ammonia while regional myocardial glucose uptake was studied with the glucose analog F-18 DG. The sensitivity of each diagnostic test for detecting cardiac involvement in Duchenne's Muscular Dystrophy was evaluated. It was highest for ammonia and glucose imaging and it was low for Thallium and radionuclide blood pool imaging

Regional myocardial metabolism in patients with acute myocardial infarction assessed by positron emission tomography

International Nuclear Information System (INIS)

Schwaiger, M.; Brunken, R.; Grover-McKay, M.; Krivokapich, J.; Child, J.; Tillisch, J.H.; Phelps, M.E.; Schelbert, H.R.

1986-01-01

Positron emission tomography has been shown to distinguish between reversible and irreversible ischemic tissue injury. Using this technique, 13 patients with acute myocardial infarction were studied within 72 hours of onset of symptoms to evaluate regional blood flow and glucose metabolism with nitrogen (N)-13 ammonia and fluorine (F)-18 deoxyglucose, respectively. Serial noninvasive assessment of wall motion was performed to determine the prognostic value of metabolic indexes for functional tissue recovery. Segmental blood flow and glucose utilization were evaluated using a circumferential profile technique and compared with previously established semiquantitative criteria. Relative N-13 ammonia uptake was depressed in 32 left ventricular segments. Sixteen segments demonstrated a concordant decrease in flow and glucose metabolism. Regional function did not change over time in these segments. In contrast, 16 other segments with reduced blood flow revealed maintained F-18 deoxyglucose uptake consistent with remaining viable tissue. The average wall motion score improved significantly in these segments (p less than 0.01), yet the degree of recovery varied considerably among patients. Coronary anatomy was defined in 9 of 13 patients: patent infarct vessels supplied 8 of 10 segments with F-18 deoxyglucose uptake, while 10 of 13 segments in the territory of an occluded vessel showed concordant decreases in flow and metabolism (p less than 0.01). Thus, positron emission tomography reveals a high incidence of residual tissue viability in ventricular segments with reduced flow and impaired function during the subacute phase of myocardial infarction. Absence of residual tissue metabolism is associated with irreversible injury, while preservation of metabolic activity identifies segments with a variable outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Association between left ventricular regional sympathetic denervation and mechanical dyssynchrony in phase analysis: a cardiac CZT study

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Gimelli, Alessia; Genovesi, Dario; Giorgetti, Assuero; Kusch, Annette [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Liga, Riccardo [Scuola Superiore Sant' Anna, Pisa (Italy); Marzullo, Paolo [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); CNR, Institute of Clinical Physiology, Pisa (Italy)

2014-05-15

To evaluate the relationships among myocardial sympathetic innervation, perfusion and mechanical synchronicity assessed with cardiac cadmium-zinc-telluride (CZT) scintigraphy. A group of 29 patients underwent an evaluation of myocardial perfusion with {sup 99m}Tc-tetrofosmin CZT scintigraphy and adrenergic innervation with {sup 123}I-metaiodobenzylguanidine (MIBG) CZT scintigraphy. The summed rest score (SRS), motion score (SMS) and thickening score (STS), as well as the summed {sup 123}I-MIBG defect score (SS-MIBG), were determined. Regional tracer uptake for both {sup 99m}Tc-tetrofosmin and {sup 123}I-MIBG was also calculated. Finally, the presence of significant myocardial mechanical dyssynchrony was evaluated in phase analysis on gated CZT images and the region of latest mechanical activation identified. Significant mechanical dyssynchrony was present in 17 patients (59 %) and associated with higher SRS (P = 0.030), SMS (P < 0.001), STS (P = 0.003) and early SS-MIBG (P = 0.037) as well as greater impairments in left ventricular ejection fraction (P < 0.001) and end-diastolic volume (P < 0.001). In multivariate analysis a higher end-diastolic volume remained the only predictor of mechanical dyssynchrony (P = 0.047). Interestingly, while in the whole population regional myocardial perfusion and adrenergic activity were strongly correlated (R = 0.68), in patients with mechanical dyssynchrony the region of latest mechanical activation was predicted only by greater impairment in regional {sup 123}I-MIBG uptake (P = 0.012) that overwhelmed the effect of depressed regional perfusion. Left ventricular mechanical dyssynchrony is associated with greater depression in contractile function and greater impairments in regional myocardial perfusion and sympathetic activity. In patients with dyssynchrony, the region of latest mechanical activation is characterized by a significantly altered adrenergic tone. (orig.)

Noninvasive detection of regional myocardial perfusion abnormality with /sup 201/Tl and /sup 81/Rb

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Narita, M; Usami, M; Kurihara, T; Kawararadani, H; Kanao, K

1977-05-01

Myocardial scintigrams were performed at rest and during exercise using /sup 201/Tl and /sup 81/Rb. Patients underwent graded ergometer exercise stress tests. In normals, myocardial images were horse-shoe or O-shaped and concentration of radionuclide was relatively uniform throughout the myocardium. In 13 patients with old myocardial infarctions, and abnormal Q waves, regional myocardial perfusion defects (cold area) were detected. Their locations correlated with sites of the abnormal Q waves. Two patients had no abnormal Q waves at the examination, but their scintigrams showed cold areas, the locations of which coincided with coronary angiographic findings. Exercise stress ECG and stress scintigrams were performed. Myocardial perfusion defects, which developed from exercise stress, were detected in 9 of 10 positive exercise ECG patients, 2 of 4 equivocal exercise ECG patients, and 2 of 10 negative exercise ECG patients. These 2 patients (exercise ECG (-), stress scintigram (+)) had typical angina. Findings of exercise stress scintigrams coincided better with clinical findings than did those of exercise ECG. These scintigraphic methods appear to be excellent for detection of noninvasive coronary heart disease noninvasively.

Evaluation of right ventricular regional wall motion in inferior myocardial infarction by cine MRI

International Nuclear Information System (INIS)

Nishino, Masami; Ohnishi, Shusaku; Hasegawa, Shinji

1991-01-01

The purpose of this study is to evaluate right ventricular regional wall motion in inferior myocardial infarction by cine MRI. Thirteen patients with inferior myocardial infarction were investigated by cine MRI and were divided into proximal group which consisted of seven patients: >90% stenosis in segment 1 or 2 of right coronary artery and distal group which consisted of six patients: >90% stenosis in segment 3 or 4 of right coronary artery. Cine MRI was performed by 1.5 tesla magnet system (Signa, GE). To depict the regional asynergy, right ventricular wall was divided into 6 segments as follows: Segments 1 and 2 were upper and lower segments in transverse planes, respectively. Segments 3 and 4 were free wall and diaphragmatic segments of outflow tract, and segments 5 and 6 were of inflow tract in sagittal planes. Our results were as follows: (1) In proximal group, right ventricular asynergy was detected in six patients but in distal group it was detected in only one patient; (2) Right ventricular asynergy was detected most frequently at diaphragmatic segments in sagittal planes; (3) All the patients who had shown the hemodynamic deterioration of right ventricle on acute phase of inferior myocardial infarction presented the broad asynergy in right ventricle; (4) Cine MRI is clinically useful in evaluating right ventricular regional wall movement and diagnosing right ventricular infarction. (author)

Early exercise training after myocardial infarction prevents contractile but not electrical remodelling or hypertrophy

NARCIS (Netherlands)

V. Bito (Virginie); M.C. de Waard (Monique); L. Biesmans (Liesbeth); I. Lenaerts (Ilse); S. Ozdemir (Semir); E.D. van Deel (Elza); Y. Abdel-Mottaleb (Yousra); R. Driesen (Ronald); P. Holemans (Patricia); D.J.G.M. Duncker (Dirk); K.R. Sipido (Karin)

2010-01-01

textabstractAims: Exercise started early after myocardial infarction (MI) improves in vivo cardiac function and myofilament responsiveness to Ca2+. We investigated whether this represents partial or complete reversal of cellular remodelling. Methods and results: Mice with MI following left coronary

Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation

International Nuclear Information System (INIS)

Mays, A.E. Jr.; Cobb, F.R.

1984-01-01

This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow

Quantitative analysis of regional myocardial performance in coronary artery disease

Science.gov (United States)

Stewart, D. K.; Dodge, H. T.; Frimer, M.

1975-01-01

Findings from a group of subjects with significant coronary artery stenosis are given. A group of controls determined by use of a quantitative method for the study of regional myocardial performance based on the frame-by-frame analysis of biplane left ventricular angiograms are presented. Particular emphasis was placed upon the analysis of wall motion in terms of normalized segment dimensions, timing and velocity of contraction. The results were compared with the method of subjective assessment used clinically.

Altered Ca fluxes and contractile state during pH changes in cultured heart cells

International Nuclear Information System (INIS)

Kim, D.; Smith, T.W.

1987-01-01

The authors studied mechanisms underlying changes in myocardial contractile state produced by intracellular (pH/sub i/) or extracellular (pH 0 ) changes in pH using cultured chick embryo ventricular cells. A change in pH 0 of HEPES-buffered medium from 7.4 to 6.0 or to 8.8 changed the amplitude of cell motion by -85 or +60%, and 45 Ca uptake at 10 s by -29 or +22%, respectively. The pH 0 induced change in Ca uptake was not sensitive to nifedipine but was Na gradient dependent. Changes in pH/sub i/ produced by NH 4 Cl or preincubation in media at pH values ranging from 6.0 to 8.8 failed to alter significantly 45 Ca uptake or efflux. However, larger changes in pH/sub i/ were associated with altered Ca uptake. Changes in pH 0 from 7.5 to 6.0 or to 8.8 were associated with initial changes in 45 Ca efflux by +17 or -18%, respectively, and these effects were not Na dependent. Exposure of cells to 20 mM NH 4 Cl produced intracellular alkalinization and a positive inotropic effect, whereas subsequent removal of NH 4 Cl caused intracellular acidification and a negative inotropic effect. There was, however, a lack of close temporal relationships between pH/sub i/ and contractile state. These results indicated that pH 0 -induced changes in contractile state in cultured heart cells are closely correlated with altered transarcolemmal Ca movements and presumably are due to these Ca flux changes

Regional wall thickening in gated myocardial perfusion SPECT in a Japanese population: effect of sex, radiotracer, rotation angles and frame rates

Energy Technology Data Exchange (ETDEWEB)

Akhter, Nasima; Nakajima, Kenichi; Okuda, Koichi; Matsuo, Shinro; Yoneyama, Tatsuya; Taki, Junichi; Kinuya, Seigo [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa, Ishikawa (Japan)

2008-09-15

Gated single-photon emission computed tomography (SPECT) imaging of myocardium by {sup 99m}Tc and {sup 201}Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT. Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution. WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by {sup 99m}Tc-labelled tracers than in {sup 201}Tl. Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique. (orig.)

Impact of Cardiac Contractility during Cerebral Blood Flow in Ischemia

Directory of Open Access Journals (Sweden)

Silver, Brian

2011-05-01

Full Text Available Objective: In cerebral regions affected by ischemia, intrinsic vascular autoregulation is often lost. Blood flow delivery depends upon cardiac function and may be influenced by neuro-endocrine mediated myocardial suppression. Our objective is to evaluate the relation between ejection fraction (EF and transcranial doppler (TCD peak systolic velocities (PSV in patients with cerebral ischemic events.Methods: We conducted a retrospective cohort study from an existing TCD registry. We evaluated patients admitted within 24 hours of onset of a focal neurological deficit who had an echocardiogram and TCD performed within 72 hours of admission.Results: We identified 58 patients from March to October 2003. Eighty-one percent (n=47 had a hospital discharge diagnosis of ischemic stroke and 18.9% (n=11 had a diagnosis of transient ischemic attack. Fourteen patients had systolic dysfunction (EF50% compared to those with systolic dysfunction (EF<50% was as follows: middle cerebral artery 62.0 + 28.6 cm/s vs. 51.0 + 23.3 cm/s, p=0.11; anterior cerebral artery 52.1 + 21.6 cm/s vs. 45.9 + 22.7 cm/s, p=0.28; internal carotid artery 56.5 + 20.1 cm/s vs. 46.4 + 18.4 cm/s, p=0.04; ophthalmic artery 18.6 + 7.2 cm/s vs. 15.3 + 5.2 cm/s, p=0.11; vertebral artery 34.0 + 13.9 cm/s vs. 31.6 + 15.0 cm/s, p=0.44.Conclusion: Cerebral blood flow in the internal carotid artery territory appears to be higher in cerebral ischemia patients with preserved left ventricular contractility. Our study was unable to differentiate pre-existing cardiac dysfunction from neuro-endocrine mediated myocardial stunning. Future research is necessary to better understand heart-brain interactions in this setting and to further explore the underlying mechanisms and consequences of neuro-endocrine mediated cardiac dysfunction. [West J Emerg Med. 2011;12(2:227-232.

Quantitative assessment of regional myocardial flow reserve using Tc-99m-sestamibi imaging. Comparison with results of O-15 water PET

International Nuclear Information System (INIS)

Tsukamoto, Takahiro; Ito, Yoshinori; Noriyasu, Kazuyuki; Morita, Koichi; Katoh, Chietsugu; Okamoto, Hiroshi; Tamaki, Nagara

2005-01-01

The aims of this study were to develop a method for quantitative estimation of the myocardial blood flow index (MBFI) and myocardial flow reserve (MFR) of the whole left ventricle using 99m technetium (Tc-99m)-sestamibi imaging. Twenty-two patients with suspected coronary artery disease and 7 controls underwent both Tc-99m-sestamibi imaging and O-15 water positron emission tomography (PET). The global MBFI was calculated on the basis of the microsphere model from the ratio of the myocardial count to the area under the time-activity curve on the aortic arch. The regional MBFI was calculated from the relative distributions of Tc-99m-sestamibi uptake values. The regional MBFI and MFR (Tc-MFR) obtained using single-photon emission computed tomography were compared with the myocardial blood flow (MBF) and MFR (PET-MFR) obtained using PET as the gold standard. Regional MBFI significantly correlated with the MBF obtained using PET. Regional Tc-MFR also correlated with the regional PET-MER, with some underestimation. These results indicate that regional MBF and MFR may be estimated by dynamic Tc-99m-sestamibi imaging and can be used for the early detection and estimation of the functional severity of coronary lesions without the need for a PET camera. (author)

In vivo assessment of regional mechanics post-myocardial infarction: A focus on the road ahead.

Science.gov (United States)

Romito, Eva; Shazly, Tarek; Spinale, Francis G

2017-10-01

Cardiovascular disease, particularly the occurrence of myocardial infarction (MI), remains a leading cause of morbidity and mortality (Go et al., Circulation 127: e6-e245, 2013; Go et al. Circulation 129: e28-e292, 2014). There is growing recognition that a key factor for post-MI outcomes is adverse remodeling and changes in the regional structure, composition, and mechanical properties of the MI region itself. However, in vivo assessment of regional mechanics post-MI can be confounded by the species, temporal aspects of MI healing, as well as size, location, and extent of infarction across myocardial wall. Moreover, MI regional mechanics have been assessed over varying phases of the cardiac cycle, and thus, uniform conclusions regarding the material properties of the MI region can be difficult. This review assesses past studies that have performed in vivo measures of MI mechanics and attempts to provide coalescence on key points from these studies, as well as offer potential recommendations for unifying approaches in terms of regional post-MI mechanics. A uniform approach to biophysical measures of import will allow comparisons across studies, as well as provide a basis for potential therapeutic markers.

Quantification of Regional Myocardial Oxygenation by Magnetic Resonance Imaging: Validation with Positron Emission Tomography

Science.gov (United States)

McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Herrero, Pilar; Misselwitz, Bernd; Gropler, Robert J.; Zheng, Jie

2011-01-01

Background A comprehensive evaluation of myocardial ischemia requires measures of both oxygen supply and demand. Positron emission tomography (PET) is currently the gold standard for such evaluations, but its use is limited due to its ionizing radiation, limited availability, and high cost. A cardiac magnetic resonance imaging (MRI) method was developed for assessing myocardial oxygenation. The purpose of this study was to evaluate and validate this technique compared to PET during pharmacologic stress in a canine model of coronary artery stenosis. Methods and Results Twenty-one beagles and small mongrel dogs without coronary artery stenosis (controls), or with moderate to severe acute coronary artery stenosis underwent MRI and PET imaging at rest and during dipyridamole vasodilation or dobutamine stress to induce a wide range of changes in cardiac perfusion and oxygenation. MRI first-pass perfusion imaging was performed to quantify myocardial blood flow (MBF) and volume (MBV). The MRI blood-oxygen-level-dependent (BOLD) technique was used to determine the myocardial oxygen extraction fraction (OEF) during pharmacologic hyperemia. Myocardial oxygen consumption (MVO2) was determined by Fick’s law. In the same dogs, 15O-water and 11C-acetate were used to measure MBF and MVO2, respectively, by PET. Regional assessments were performed for both MR and PET. MRI data correlated nicely with PET values for MBF (R2 = 0.79, P < 0.001), MVO2 (R2 = 0.74, P < 0.001), and OEF (R2 = 0.66, P < 0.01). Conclusions Cardiac MRI methods may provide an alternative to radionuclide imaging in settings of myocardial ischemia. Our newly developed quantitative MRI oxygenation imaging technique may be a valuable non-invasive tool to directly evaluate myocardial energetics and efficiency. PMID:19933371

Phenylephrine postconditioning increases myocardial injury: Are alpha-1 sympathomimetic agonist cardioprotective?

Directory of Open Access Journals (Sweden)

Iordanis Mourouzis

2014-01-01

Full Text Available Objective: We studied effects of phenylephrine (PHE on postischemic functional recovery and myocardial injury in an ischemia-reperfusion (I-R experimental model. Materials and Methods: Rat hearts were Langendorff-perfused and subjected to 30 min zero-flow ischemia (I and 60 min reperfusion (R. During R PHE was added at doses of 1 μM (n = 10 and 50 μM (n = 12. Hearts (n = 14 subjected to 30 and 60 min of I-R served as controls. Contractile function was assessed by left ventricular developed pressure (LVDP and the rate of increase and decrease of LVDP; apoptosis by fluorescent imaging targeting activated caspase-3, while myocardial injury by lactate dehydrogenase (LDH released during R. Activation of kinases was measured at 5, 15, and 60 min of R using western blotting. Results: PHE did not improve postischemic contractile function. PHE increased LDH release (IU/g; 102 ± 10.4 (Mean ± standard error of mean control versus 148 ± 14.8 PHE (1, and 145.3 ± 11 PHE (50 hearts, (P < 0.05. PHE markedly increased apoptosis. Molecular analysis showed no effect of PHE on the activation of proapoptotic c-Jun N-terminal kinase signaling; a differential pattern of p38 mitogen activated protein kinase (MAPK activation was found depending on the PHE dose used. With 1 μM PHE, p-p38/total-p38 MAPK levels at R were markedly increased, indicating its detrimental effect. With PHE 50 μM, no further changes in p38 MAPK were seen. Activation of Akt kinase was decreased implying involvement of different mechanisms in this response. Conclusions: PHE administration during reperfusion does not improve postischemic recovery due to exacerbation of myocardial necrosis and apoptosis. This finding may be of clinical and therapeutic relevance.

Increased Regional Epicardial Fat Volume Associated with Reversible Myocardial Ischemia in Patients with Suspected Coronary Artery Disease

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Khawaja, Tuba; Greer, Christine; Thadani, Samir R.; Kato, Tomoko S.; Bhatia, Ketan; Shimbo, Daichi; Konkak, Andrew; Bokhari, Sabahat; Einstein, Andrew J.; Schulze, P. Christian

2015-01-01

Epicardial adipose tissue is a source of pro-inflammatory cytokines and has been linked to the development of coronary artery disease. No study has systematically assessed the relationship between local epicardial fat volume (EFV) and myocardial perfusion defects. We analyzed EFV in patients undergoing SPECT myocardial perfusion imaging combined with computed tomography (CT) for attenuation correction. Low-dose CT without contrast was performed in 396 consecutive patients undergoing SPECT imaging for evaluation of coronary artery disease. Regional thickness, cross-sectional areas, and total EFV were assessed. 295 patients had normal myocardial perfusion scans and 101 had abnormal perfusion scans. Mean EFVs in normal, ischemic, and infarcted hearts were 99.8 ± 82.3 cm3, 156.4 ± 121.9 cm3, and 96.3 ± 102.1 cm3, respectively (P < 0.001). Reversible perfusion defects were associated with increased local EFV compared to normal perfusion in the distribution of the right (69.2 ± 51.5 vs 46.6 ± 32.0 cm3; P = 0.03) and left anterior descending coronary artery (87.1 ± 76.4 vs 46.7 ± 40.6 cm3; P = 0.005). Our results demonstrate increased regional epicardial fat in patients with active myocardial ischemia compared to patients with myocardial scar or normal perfusion on nuclear perfusion scans. Our results suggest a potential role for cardiac CT to improve risk stratification in patients with suspected coronary artery disease. PMID:25339129

Genome sequence of Haloplasma contractile, an unusual contractile bacterium from a deep-sea anoxic brine lake.

KAUST Repository

Antunes, Andre; Alam, Intikhab; El Dorry, Hamza; Siam, Rania; Robertson, Anthony J.; Bajic, Vladimir B.; Stingl, Ulrich

2011-01-01

We present the draft genome of Haloplasma contractile, isolated from a deep-sea brine and representing a new order between Firmicutes and Mollicutes. Its complex morphology with contractile protrusions might be strongly influenced by the presence of seven MreB/Mbl homologs, which appears to be the highest copy number ever reported.

Genome sequence of Haloplasma contractile, an unusual contractile bacterium from a deep-sea anoxic brine lake.

KAUST Repository

Antunes, Andre

2011-09-01

We present the draft genome of Haloplasma contractile, isolated from a deep-sea brine and representing a new order between Firmicutes and Mollicutes. Its complex morphology with contractile protrusions might be strongly influenced by the presence of seven MreB/Mbl homologs, which appears to be the highest copy number ever reported.

Usefulness of multimodality imaging for detection of myocardial infarction in patients with advanced kidney failure: case report

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Veras, Mariana Ferreira; Azevedo, Jader Cunha de; Gamarski, Moisés; Mesquita, Evandro Tinoco; Mesquita, Cláudio Tinoco, E-mail: fvmari@gmail.com [Hospital Procardíaco, Rio de Janeiro, RJ (Brazil); Alves, José Galvão [Centro Universitário de Volta Redonda, RJ (Brazil)

2016-01-15

The third universal definition of acute myocardial infarction (AMI) is based on the elevation of troponin in association with ischemic symptoms, electrocardiographic changes and imaging findings. In patients with chest pain, the diagnosis of AMI is performed by dosing serum markers of myocardial necrosis, particularly troponins, by means of changes in 12 - lead electrocardiogram (ECG) or by identifying changes in the contractile dynamics of the left ventricle to the transthoracic echocardiogram. In some cases, confounding factors may hamper the diagnosis, such as: (a) presence of previous changes in the baseline ECG, especially LBBB; (b) elevations of myocardial necrosis markers (MNM) resulting from situations other than AMI and; (c) old changes in contractility detected by transthoracic ECG. Serum cardiac troponin (Tn) is the most specific and most used MNM for the diagnosis of AMI. Nevertheless, in some situations troponin elevation may not be due to an AMI, as in cases of acute pulmonary embolism, acute pericarditis, severe heart failure, myocarditis, and sepsis and kidney failure. Patients with kidney failure have high probability of concurrent cardiovascular disease. Furthermore, the cross-reacting proteins interfering with skeletal muscle, analytical imprecision and interactions with the dialysis membrane may cause elevation of troponin in 7% to 17% of patients with kidney failure. When in doubt about diagnosis of AMI, {sup 99m}Technetium pyrophosphate myocardial scintigraphy ({sup 99m}Tc-PYP) stands out as a noninvasive method capable of identifying areas of myocardial necrosis, thus helping in the diagnosis of AMI. {sup 99m}Tc-labeled phosphonate agents undergo chemical absorption with calcium. A large influx of calcium occurs during the evolutionary process of AMI. The calcium flows into the intracellular space and myocardial concentration of {sup 99m}Tc-PYP follows such increase, with a maximum peak uptake about 48 to 72 hours after the acute event. The

Clinical Significance of Reverse Redistribution Phenomenon on Delayed Tc-99m Tetrofosmin Myocardial Perfusion Imaging in Patients with Acute Myocardial Infarction

International Nuclear Information System (INIS)

Park, Soon Ah; Kim, Dae Weung; Kim, Chang Guhn; Jeong, Jin Won; Kim, Nam Ho; Yun, Kyeong Ho

2009-01-01

This study was performed to investigate the clinical significance of reverse redistribution (RR) phenomenon detected on delayed Tc-99m tetrofosmin myocardial single photon emission computed tomography (SPECT) in patients with acute myocardial infarction after revascularization. A Tc-99m tetrofrosmin myocardial SPECT was performed in 67 consecutive patients after revascularization for acute myocardial infarction. Myocardial SPECT imaging was performed for early imaging at 40 min and for delayed imaging at 180 min after reinjection at myocardial stress. Regional myocardial uptakes were scored by 4-point scoring in the left ventricular wall divided into 17 segments. Reverse redistribution was defined as an increase of more than 2 point in the activity score on the delayed image. Follow-up myocardial SPECT and coronary angiography (CAG) were performed 9 months later. On myocardial SPECT performed following revascularization, RR was observed in 100 of all 319 segments (31%) and in 43 patients (64%). The abnormalities of perfusion and regional wall motion were more severe in the patients with RR compared to those without RR (p<0.05). On follow-up myocardial SPECT, the myocardial perfusion, regional wall motion, and myocardial thickness were significantly improved in the patients with RR (p<0.05) however, these changes were not significant in those without RR. There was no significant difference between the patients with RR and those without RR in the occurrence of restenosis on CAG. In patients with acute myocardial infarction, the regions showing the RR phenomenon on delayed Tc-99m tetrofosmin SPECT may reflect viable myocardium and indicate recovery of salvaged myocardium

Recently active contractile deformation in the forearc of southern Peru

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Hall, S. R.; Farber, D.; Audin, L.; Finkel, R. C.

2010-12-01

In the Precordillera and Western Cordillera of southern Peru (14°-18°S), vast pediment surfaces have been abandoned through drainage diversion and river incision, with the major drainages carving deep canyons. Within this region, we have identified range-sub-parallel contractile structures that accommodate significant distributed crustal deformation. Young geomorphic features document both the presence and youthfulness of these contractile structures. Here, we determine exposure ages on geomorphic features such as pediment surfaces and fluvial terraces using in situ produced cosmogenic radionuclides, in conjunction with field and remote mapping. This chronologic data reveals that ancient surfaces have been preserved as a result of very low erosion rates. We measure this rate to be chronology and geomorphic mapping, we calculate a Pleistocene river incision rate of ~0.3mm/yr determined from data collected along exoreic rivers. This rate is consistent with longer-term incision rates measured in other localities along this margin. We suggest that, in this region of southern Peru, the steep western wedge of the Andean margin supports the high topography of the Altiplano through a combination of uplift along steeply dipping contractile west-vergent structures and isostatic responses to the focused removal of large amounts of crustal material through canyon incision. Further, that these range sub-parallel structures are related at depth to a thrust system that plays a role in not only the maintenance of the Andean margin, but potentially in its formation as well.

Is the time between onset of pain and restoration of patency of infarct-related artery shortened in patients with myocardial infarction? The effects of the Kielce Region System for Optimal Management of Acute Myocardial Infarction

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Marcin Sadowski

2014-09-01

Full Text Available Introduction : The importance of delay in the restoration of infarct-related artery patency in patients with myocardial infarction was discussed, and actions were undertaken in the Kielce Region aimed at shortening this time within the System for Optimal Management of Acute Myocardial Infarction. Aim of the research: To evaluate the effectiveness of shortening time delays during transport of patients and diagnostics of myocardial infarction in the Kielce Region. Material and methods: Time delays were analysed in 5,934 patients with ST-segment elevation myocardial infarction (STEMI, hospitalised in cardiology wards with interventional cardiology on 24-hour duty, during the period 2008–2012. Time delays were analysed between the onset of myocardial infarction pain and undertaking treatment – T1 and T2 time – within which a patient with myocardial infarction, after admission to hospital, has intervention performed on infarct-related coronary artery. Results : During the period 2008–2012, the median T1 time was successfully shortened from 355 to 203 min, and the T2 time from 101 to 48 min. Conclusions: The effectiveness of the system was confirmed, and the necessity for further improvement of the system indicated.

Validation of quantitation of regional myocardial blood flow in vivo with 11C-labeled human albumin microspheres and positron emission tomography

International Nuclear Information System (INIS)

Wilson, R.A.; Shea, M.J.; De Landsheere, C.M.; Turton, D.; Brady, F.; Deanfield, J.E.; Selwyn, A.P.

1984-01-01

Use of radiolabeled microspheres is a standard method to measure regional myocardial perfusion in animals. Human albumin microspheres have been given safely to patients, but positron-emitting 67 Ga-labeled human albumin microspheres are characterized by an unstable radiolabel. A new labeling procedure that covalently binds 11 C to human albumin microspheres via 11 CH 3 I was developed. Seven open-chest and two closed-chest dogs were studied. Reference and 11 C-labeled human albumin microspheres (2 to 25 mCi) were both injected into the left atrium. Positron tomographic images were obtained of the myocardial distribution of the 11 C-labeled microspheres. Timed arterial withdrawal was used for both reference gamma-labeled microspheres and 11 C-labeled human albumin microspheres. Regional myocardial perfusion calculated by this technique correlated well with values obtained with reference microspheres over a range of 0.2 to 3.5 ml/min/g. Thus, 11 C human albumin microspheres are stable radiochemically and can be used as a quantitative measure of regional myocardial perfusion

Effect of eating on thallium-201 myocardial redistribution after myocardial ischemia

International Nuclear Information System (INIS)

Angello, D.A.; Wilson, R.A.; Palac, R.T.

1987-01-01

To determine whether eating a high-carbohydrate meal between initial and delayed postexercise thallium-201 (Tl-201) imaging affects detection of Tl-201 redistribution during exercise stress testing, 16 patients with stable angina performed 2 Tl-201 treadmill exercise stress tests within a 14-day interval. Immediately after initial postexercise imaging, patients either drank a commercially available instant breakfast preparation for the intervention test or drank an equivalent volume of water for the control test. Comparable exercise workloads were achieved by exercising patients to the same heart rate for both tests. The order of the 2 (intervention and control) tests were randomized. All patients had at least 1 region of Tl-201 myocardial redistribution on either their eating or control test scans, although only 7 of the 16 had positive treadmill exercise test responses. Forty-six regions showing Tl-201 myocardial redistribution were identified in all 144 regions examined. Significantly more of these regions were identified on control test scans than on eating test scans: 11 of 46 on both test scans, 6 of 46 only on eating test scans and 29 of 46 only on control scans (p less than 0.001). Consistent with results of the quantitative regional analysis, the percentage of Tl-201 clearance over 4 hours in the 46 Tl-201 myocardial redistribution regions was 39 +/- 8% for the eating tests and 29 +/- 8% for control tests (mean +/- standard deviation, p less than 0.003). In 4 patients diagnosis of transient ischemia would have been missed because their 14 Tl-201 myocardial redistribution regions were detected only on the control test scans

Reproducibility of non-invasive measurement for left ventricular contractility using gated myocardial SPECT

International Nuclear Information System (INIS)

Kim, Kyeon Min; Lee, Dong Soo; Kim, Yu Kyeong; Cheon, Gi Jeong; Kim, Seok Ki; Chung, June Key; Lee, Myung Chul

2001-01-01

We tried to establish the reproducibility of the measurement of maximal elastance (Emax) and to compare the degree of the reproducibility of two estimation methods: single pressure-volume loop method and parameter optimization method. In 47 patients (42 males and 5 females, 53 ± 10 years old) with suspected coronary artery disease (ejection fraction; 22-68%), gated Tc-99m MIBI myocardial SPECT and arterial tonometry were acquired, In 11 patients among these 47 patients, gated SPECT and tonometry were performed twice consecutively with patients in situ. Emax and void volume (Vo) were estimated using single pressure-volume loop method of Lee and parameter optimization method based on linear approximation of Yoshizawa. Correlation between the consecutive measurements by each method and correlation between the two estimation methods were compared. Reproducibility of Emax (r=0.96) and Vo (r=0.99) by single pressure-volume method was better than the reporducibility of Emax (r=0.89) and Vo (r=0.64) by parameter optimization method. Correlations of Emax and Vo were fair between the two methods. The correlation of Emax (r=0.77) was better thn that of Vo (r=0.65). Reproducibiity of Emax measurement by single pressure-volume loop method using gated myocardial SPECT and arterial tonometry was excellent. Reproducibility by parameter optimization method was also but was less than that achieved by single pressure-volume method

Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

Science.gov (United States)

McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

2009-01-01

OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

Three-dimension structure of ventricular myocardial fibers after myocardial infarction

Directory of Open Access Journals (Sweden)

Li Libin

2010-11-01

Full Text Available Abstract Background To explore the pathological changes of three-dimension structure of ventricular myocardial fibers after anterior myocardial infarction in dog heart. Methods Fourteen acute anterior myocardial infarction models were made from healthy dogs (mean weight 17.6 ± 2.5 kg. Six out of 14 dogs with old myocardial infarction were sacrificed, and their hearts were harvested after they survived the acute anterior myocardial infarction for 3 months. Each heart was dissected into ventricular myocardial band (VMB, morphological characters in infarction region were observed, and infarct size percents in descending segment and ascending segment were calculated. Results Six dog hearts were successfully dissected into VMB. Uncorresponding damages in myocardial fibers of descending segment and ascending segment were found in apical circle in anterior wall infarction. Infarct size percent in the ascending segment was significantly larger than that in the descending segment (23.36 ± 3.15 (SD vs 30.69 ± 2.40%, P = 0.0033; the long axis of infarction area was perpendicular to the orientation of myocardial fibers in ascending segment; however, the long axis of the infarction area was parallel with the orientation of myocardial fibers in descending segment. Conclusions We found that damages were different in both morphology and size in ascending segment and descending segment in heart with myocardial infarction. This may provide an important insight for us to understand the mechanism of heart failure following coronary artery diseases.

Asymptomatic myocardial ischemia following cold provocation

International Nuclear Information System (INIS)

Shea, M.J.; Deanfield, J.E.; deLandsheere, C.M.; Wilson, R.A.; Kensett, M.; Selwyn, A.P.

1987-01-01

Cold is thought to provoke angina in patients with coronary disease either by an increase in myocardial demand or an increase in coronary vascular resistance. We investigated and compared the effects of cold pressor stimulation and symptom-limited supine bicycle exercise on regional myocardial perfusion in 35 patients with stable angina and coronary disease and in 10 normal subjects. Regional myocardial perfusion was assessed with positron emission tomography and rubidium-82. Following cold pressor stimulation 24 of 35 patients demonstrated significant abnormalities of regional myocardial perfusion with reduced cation uptake in affected regions of myocardium: 52 +/- 9 to 43 +/- 9 (p less than 0.001 vs normal subjects). Among these 24 patients only nine developed ST depression and only seven had angina. In contrast, 29 of 35 patients underwent supine exercise, and abnormal regional myocardial perfusion occurred in all 29, with a reduction in cation intake from 48 +/- 10 to 43 +/- 14 (p less than 0.001 vs normal subjects). Angina was present in 27 of 29 and ST depression in 25 of 29. Although the absolute decrease in cation uptake was somewhat greater following cold as opposed to exercise, the peak heart rate after cold was significantly lower than that after exercise (82 +/- 12 vs 108 +/- 16 bpm, p less than 0.05). Peak systolic blood pressures after cold and exercise were similar (159 +/- 24 vs 158 +/- 28). Thus, cold produces much more frequent asymptomatic disturbances of regional myocardial perfusion in patients with stable angina and coronary disease than is suggested by pain or ECG changes

Noninvasive quantification of regional myocardial perfusion with rubidium-82 and positron emission tomography. Exploration of a mathematical model

International Nuclear Information System (INIS)

Herrero, P.; Markham, J.; Shelton, M.E.; Weinheimer, C.J.; Bergmann, S.R.

1990-01-01

Positron emission tomography (PET) centers without cyclotrons use generator-produced rubidium-82 (82Rb) for assessment of myocardial perfusion. The aim of the present study was to determine whether myocardial blood flow could be assessed quantitatively with 82Rb and PET. Because the myocardial extraction fraction of 82Rb varies inversely and nonlinearly with flow and cannot be measured conveniently with PET, we used an experimentally derived mathematical function defining the relation between single-pass extraction fraction of 82Rb and flow to obviate the necessity of measuring the extraction fraction directly. Myocardial blood flow in absolute terms (ml/g/min) was estimated from dynamic PET scans after intravenous administration of 82Rb in intact dogs and compared with flows measured with radiolabeled microspheres. In 36 comparisons in 13 dogs studied at rest, or after coronary occlusion, reperfusion, or after coronary hyperemia induced with intravenous dipyridamole, over the flow range from 0.2 to 2.0 ml/g/min, estimates of perfusion with rubidium correlated well with flows measured concomitantly with microspheres, although there was a slight underestimation of flow with rubidium (flow by 82Rb = 0.92 x flow by microspheres-0.021, r = 0.83). In general, estimates of flow in ischemic regions were less reliable than estimates for regions with normal flow. Thus, although the relation between myocardial extraction and retention of 82Rb and flow can vary under a variety of physiological and pathophysiological conditions, this study demonstrates the ability to obtain quantitative estimates of myocardial blood flow with 82Rb and PET under carefully defined conditions without measuring the extraction fraction directly

Nitrogen-13-labeled ammonia for myocardial imaging

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Walsh, W.F.; Fill, H.R.; Harper, P.V.

1977-01-01

Cyclotron-produced nitrogen-13 (half-life 10 min), as labeled ammonia (/sup 13/NH/sub 4//sup +/), has been evaluated as a myocardial perfusion imaging agent. The regional myocardial uptake of /sup 13/NH/sub 4//sup +/ has been shown to be proportional to regional tissue perfusion in animal studies. Intravenously administered /sup 13/NH/sub 4//sup +/ is rapidly cleared from the circulation, being extracted by the liver (15 percent), lungs, myocardium (2 percent--4 percent), brain, kidney, and bladder. Myocardial ammonia is metabolized mainly to glutamine via the glutamine synthetase pathway. Pulmonary uptake is substantial, but usually transient, except in smokers where clearance may be delayed. The positron annihilation irradiation (511 keV) of /sup 13/N may be imaged with a scintillation camera, using either a specially designed tungsten collimator or a pinhole collimator. After early technical problems with collimation and the production method of /sup 13/NH/sub 4//sup +/ were overcome, reproducible high quality myocardial images were consistently obtained. The normal myocardial image was established to be of a homogeneous ''doughnut'' configuration. Imaging studies performed in patients with varying manifestations of ischemic and valvular heart disease showed a high incidence of localized perfusion defects, especially in patients with acute myocardial infarction. Sequential studies at short intervals in patients with acute infarction showed correlation between alterations in regional perfusion and the clinical course of the patient. It is concluded that myocardial imaging with /sup 13/NH/sub 4//sup +/ and a scintillation camera provides a valid and noninvasive means of assessing regional myocardial perfusion. This method is especially suitable for sequential studies of acute cardiac patients at short intervals. Coincidence imaging of the 511 keV annihilation irradiation provides a tomographic and potentially quantitative assessment of the

Tl myocardial SPECT demonstrates importance of collateral circulation in patients with myocardial infarction

International Nuclear Information System (INIS)

Hattori, Fukunori

1997-01-01

The influence of collateral circulation on the preservation of myocardial viability and the efficacy of drug therapy and PTCA were evaluated by exercise 201 Tl myocardial SPECT before and after treatment. Thirty-five patients with a history of myocardial infarction resulting from total or subtotal obstruction of the responsible coronary artery were divided into four groups, according to the method of the treatment and the degree of collateral blood flow. Patients in groups A and B received drug therapy and displayed developed and undeveloped collateral circulation, respectively. Groups C and D received PTCA and displayed developed and undeveloped collateral circulation, respectively. Tl myocardial SPECT was performed before treatment to record the extent of redistribution to the occluded region, the degree of myocardial viability and the nature and extent of the ischemic lesion. In group A, myocardial perfusion improved, although redistribution remained in all cases, while in group B, 4 of 7 cases improved after drug therapy. In group C, myocardial perfusion improved in all cases, and redistribution disappeared in 7 of 12 cases. 5 of 6 cases improved in group D after PTCA. After drug therapy, the %Tl uptake in the infarcted region improved significantly in initial and delayed images of patients in group A. The differences in initial and delayed images in group B before and after drug therapy were not significant. In contrast, groups C and D both registered significant improvement in initial and delayed images after PTCA. The washout rate improved significantly in groups A, C and D after their respective treatments. These results suggest that developed collateral circulation helps to preserve myocardial viability in cases of myocardial infarction. Myocardial perfusion improved after drug therapy in cases with developed collateral circulation, and in patients with developed and undeveloped collateral circulation receiving PTCA. (K.H.)

Dependence of intramyocardial pressure and coronary flow on ventricular loading and contractility: a model study.

Science.gov (United States)

Bovendeerd, Peter H M; Borsje, Petra; Arts, Theo; van De Vosse, Frans N

2006-12-01

The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of three-dimensional wall stress, nonlinear characteristics of the coronary bed, and extravascular fluid exchange. With the associated increase in the number of model parameters, a detailed parameter sensitivity analysis has become difficult. Therefore we investigated the primary relations between ventricular pressure and volume, wall stress, intramyocardial pressure and coronary blood flow, with a mathematical model with a limited number of parameters. The model replicates several experimental observations: the phasic character of coronary inflow is virtually independent of maximum ventricular pressure, the amplitude of the coronary flow signal varies about proportionally with cardiac contractility, and intramyocardial pressure in the ventricular wall may exceed ventricular pressure. A parameter sensitivity analysis shows that the normalized amplitude of coronary inflow is mainly determined by contractility, reflected in ventricular pressure and, at low ventricular volumes, radial wall stress. Normalized flow amplitude is less sensitive to myocardial coronary compliance and resistance, and to the relation between active fiber stress, time, and sarcomere shortening velocity.

Pharmacological prevention of reperfusion injury in acute myocardial infarction. A potential role for adenosine as a therapeutic agent.

Science.gov (United States)

Quintana, Miguel; Kahan, Thomas; Hjemdahl, Paul

2004-01-01

The concept of reperfusion injury, although first recognized from animal studies, is now recognized as a clinical phenomenon that may result in microvascular damage, no-reflow phenomenon, myocardial stunning, myocardial hibernation and ischemic preconditioning. The final consequence of this event is left ventricular (LV) systolic dysfunction leading to increased morbidity and mortality. The typical clinical case of reperfusion injury occurs in acute myocardial infarction (MI) with ST segment elevation in which an occlusion of a major epicardial coronary artery is followed by recanalization of the artery. This may occur either spontaneously or by means of thrombolysis and/or by primary percutaneous coronary intervention (PCI) with efficient platelet inhibition by aspirin (acetylsalicylic acid), clopidogrel and glycoprotein IIb/IIIa inhibitors. Although the pathophysiology of reperfusion injury is complex, the major role that neutrophils play in this process is well known. Neutrophils generate free radicals, degranulation products, arachidonic acid metabolites and platelet-activating factors that interact with endothelial cells, inducing endothelial injury and neutralization of nitrous oxide vasodilator capacity. Adenosine, through its multi-targeted pharmacological actions, is able to inhibit some of the above-mentioned detrimental effects. The net protective of adenosine in in vivo models of reperfusion injury is the reduction of the infarct size, the improvement of the regional myocardial blood flow and of the regional function of the ischemic area. Additionally, adenosine preserves the post-ischemic coronary flow reserve, coronary blood flow and the post-ischemic regional contractility. In small-scale studies in patients with acute MI, treatment with adenosine has been associated with smaller infarcts, less no-reflow phenomenon and improved LV function. During elective PCI adenosine reduced ST segment shifts, lactate production and ischemic symptoms. During the

Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

Science.gov (United States)

Ianuzzo, C. D.; Chen, V.

1977-01-01

Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

Effect of collateral circulation on myocardial protection in patients with acute myocardial infarction. Comparison of technetium-99m-tetrofosmin myocardial single photon emission computed tomography and coronary angiography

International Nuclear Information System (INIS)

Yoshida, Michi; Kondo, Makoto; Abe, Yoshiteru; Kubota, Tomoyuki; Matsuoka, Ryota; Araki, Makoto; Tanio, Hitoshi; Doyama, Kiyoshi

2006-01-01

Evaluation of myocardial blood flow from collateral vessels into the infarct area has been estimated by coronary angiography. In patients with acute myocardial infarction with Thrombolysis in Myocardial Infarction (TIMI) 0 flow, myocardial tracer uptake on single photon emission computed tomography (SPECT) images can predict the collateral blood flow in the infarct area if technetium (Tc)-99m-tetrofosmin was administered before recanalization. The present study investigated whether collateral blood flow evaluated by myocardial scintigraphy is a good predictor of myocardial salvage in patients with acute myocardial infarction. The study group consisted of 30 patients (mean age 65±14 years, 23 males, 7 females) with first acute myocardial infarction and coronary angiography evidence of total occlusion (TIMI 0) within 12 hr after the onset. All patients had one vessel disease related to infarction and TIMI 3 flow after percutaneous coronary intervention (PCI). Tc-99m-tetrofosmin was injected intravenously before the PCI. The regional severity score index (RSSI) was obtained from SPECT using the 17 segment method with the four-point scoring system. Myocardial viability was evaluated by the RSSI obtained from thallium-glucose-insulin infusion SPECT after 1 week and regional wall motion score index obtained from echocardiography during the chronic phase. The patients were divided into two groups according to the angiographic collateral finding. There were no differences in RSSI on thallium-glucose-insulin SPECT and regional wall motion score between the good collateral group (n=8) and poor collateral group (n=22). Myocardial Tc-99m-tetrofosmin RSSI was similar in these groups. On the other hand, the patients were divided according to Tc-99m-tetrofosmin scintigraphic evaluation before PCI. RSSI on thallium-glucose-insulin SPECT was significantly greater (0.7±0.5 vs 1.5±0.4, p<0.01) and regional wall motion score was significantly less (1.46±0.50 vs 2.08±0.78, p<0

Limitations of regional myocardial thallium clearance for identification of disease in individual coronary arteries

International Nuclear Information System (INIS)

Becker, L.C.; Rogers, W.J. Jr.; Links, J.M.; Corn, C.

1989-01-01

The purpose of this study was to critically evaluate the usefulness of postexercise regional myocardial thallium-201 clearance for identifying disease in individual coronary arteries. Exercise and redistribution planar imaging studies were performed in 114 subjects, including 19 normal volunteers and 95 patients undergoing cardiac catheterization (70 with and 25 without greater than or equal to 50% narrowing in one or more coronary arteries). Thallium clearance was measured from predefined myocardial regions corresponding to the left anterior descending, left circumflex and right coronary arteries and was expressed as the percent decrease in activity at 4 h, assuming monoexponential clearance. In regions perfused by a normal or insignificantly diseased coronary artery, mean 4 h clearance was 58.9 +/- 9.4% for normal volunteers, 43.1 +/- 15.5% for catheterized patients without coronary artery disease and 36.3 +/- 24.9% for catheterized patients with coronary artery disease (p less than 0.001 patients with coronary artery disease versus normal volunteers). Clearance from normal regions was significantly associated with two measures of exercise performance: percent of predicted maximal heart rate achieved (r = 0.49) and exercise duration (r = 0.35). In regions perfused by a stenotic coronary artery, mean clearance was lower (31.1 +/- 19.8%) but was not significantly different from that in normal regions in the same patients. Clearance from diseased regions was also associated with maximal exercise heart rate (r = 0.28) and exercise duration (r = 0.41), but not with percent coronary artery stenosis (r = 0.02). After taking exercise performance into account, the number of diseased vessels or the presence or absence of disease in a given vessel had little influence on regional thallium clearance

Efficacy of coronary artery reconstruction in maintaining myocardial viability. Quntitative determination of local myocardial circulation with 13NH3 myocardial positron emission tomography

International Nuclear Information System (INIS)

Kobayashi, Satoshi; Takaba, Toshihiro; Kume, Masato; Kashima, Toshitaka; Michihata, Tetsuro.

1996-01-01

Thirty patients (280 areas) whose bypass grafts remained patent after surgical reconstruction of the coronary artery were examined. Before and after reconstruction, local myocardial blood circulation in infarcted regions and post-stenotic regions was measured by 13 NH 3 myocardial positron emission computed tomography (PET) at rest or during physical exercise in order to evaluate the efficacy of coronary artery reconstruction. Before operation, mean blood flow in post-stenotic regions (n=198) was 65±15 ml/min/100 g at rest and 85±23 ml/min/100 g during exercise. After coronary artery bypass grafting (CABG), mean blood flow was increased to 78±21 ml/min/100 g at rest (p, 0.01) and 105±32 ml/min/100 g during exercise (p<0.01). In infarcted regions (n=82), mean blood flow before operation was 51±23 ml/min/100 g at rest and 69±23 ml/min/100 g during exercise. After CABG, it increased to 62±19 ml/min/100 g at rest (p<0.01) and 81±29 ml/min/100 g during exercise (p<0.01). Thus, significant increases in blood flow were observed in both post-stenotic and infarcted regions at rest and physical exercise after operation. The regions of infarction were divided into three groups based on local myocardial blood flow at rest before operation: Group I: greater than 45 ml/min/100 g (n=35); Group II: less than 45 ml/min/100 g (n=30) but greater than 30 ml/min/100 g; and Group III: less than 30 ml/min/100 g (n=30). The efficacy of reconstruction was compared among these groups. The group with preoperative myocardial blood flow greater than 30 ml/min/100 g had increased blood flow after operation, indicating myocardial viability. (author)

Time course of regional myocardial glucose metabolism after transient ischemia assessed by positron emission tomography

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Hoshizaki, Hiroshi (Gunma Univ., Maebashi (Japan). School of Medicine)

1992-11-01

The purpose of this study was to examine the significance of glucose metabolism in ischemic canine myocardium after reperfusion. Transient ischemia was induced by 90 or 180 minutes occlusion of the left anterior descending coronary artery. Twelve hours and 4 weeks after reperfusion, myocardial blood flow (MBF) and glucose metabolism were assessed (with H[sub 2][sup 15]O and [sup 18]F-FDG, respectively) by positron emission tomography (PET) under the fasting state, and the metabolic findings were compared with the histologic examination. Glucose metabolism in ischemic regions was inversely related to the amount of tissue necrosis 12 hours and 4 weeks after reperfusion (r=-0.89 and r=-0.82, respectively). The perfusion-metabolism mismatch pattern was seen in the area with less than 10 percent necrosis 12 hours after reperfusion, but this pattern disappeared after 4 weeks. The area with 10 to 50 percent necrosis showed the mismatch pattern until 4 weeks after reperfusion, and in the area with more than 50 percent necrosis, perfusion-metabolism concordantly decreased. Thus, metabolic index assessed early after reperfusion by PET identified myocardial viability, and the perfusion-metabolism mismatch pattern sustained in relation to the degree of ischemic injury. Since some regions estimated to be irreversible by PET were viable by the histologic examination, PET study might underestimate the myocardial viability. (author).

Propofol reduced myocardial contraction of vertebrates partly by mediating the cyclic AMP-dependent protein kinase phosphorylation pathway

International Nuclear Information System (INIS)

Sun, Xiaotong; Zhang, Xinyu; Bo, Qiyu; Meng, Tao; Lei, Zhen; Li, Jingxin; Hou, Yonghao; Yu, Xiaoqian; Yu, Jingui

2016-01-01

Propofol inhibits myocardial contraction in a dose dependent manner. The present study is designed to examine the effect of propofol on PKA mediated myocardial contraction in the absence of adrenoreceptor agonist. The contraction of isolated rat heart was measured in the presence or absence of PKA inhibitor H89 or propofol, using a pressure transducer. The levels of cAMP and PKA kinase activity were detected by ELISA. The mRNA and total protein or phosphorylation level of PKA and downstream proteins were tested in the presence or absence of PKA inhibitor H89 or propofol, using RT-PCR, QPCR and western blotting. The phosphorylation level of PKA was examined thoroughly using immunofluorescence and PKA activity non-radioactive detection kit. Propofol induced a dose-dependent negative contractile response on the rat heart. The inhibitory effect of high concentration propofol (50 μM) with 45% decease of control could be partly reversed by the PKA inhibitor H89 (10 μM) and the depressant effect of propofol decreased from 45% to 10%. PKA kinase activity was inhibited by propofol in a dose-dependent manner. Propofol also induced a decrease in phosphorylation of PKA, which was also inhibited by H89, but did not alter the production of cAMP and the mRNA levels of PKA. The downstream proteins of PKA, PLN and RyR2 were phosphorylated to a lesser extent with propofol or H89 than control. These results demonstrated that propofol induced a negative myocardial contractile response partly by mediating the PKA phosphorylation pathway.

Usefulness of myocardial parametric imaging to evaluate myocardial viability in experimental and in clinical studies.

Science.gov (United States)

Korosoglou, G; Hansen, A; Bekeredjian, R; Filusch, A; Hardt, S; Wolf, D; Schellberg, D; Katus, H A; Kuecherer, H

2006-03-01

To evaluate whether myocardial parametric imaging (MPI) is superior to visual assessment for the evaluation of myocardial viability. Myocardial contrast echocardiography (MCE) was assessed in 11 pigs before, during, and after left anterior descending coronary artery occlusion and in 32 patients with ischaemic heart disease by using intravenous SonoVue administration. In experimental studies perfusion defect area assessment by MPI was compared with visually guided perfusion defect planimetry. Histological assessment of necrotic tissue was the standard reference. In clinical studies viability was assessed on a segmental level by (1) visual analysis of myocardial opacification; (2) quantitative estimation of myocardial blood flow in regions of interest; and (3) MPI. Functional recovery between three and six months after revascularisation was the standard reference. In experimental studies, compared with visually guided perfusion defect planimetry, planimetric assessment of infarct size by MPI correlated more significantly with histology (r2 = 0.92 versus r2 = 0.56) and had a lower intraobserver variability (4% v 15%, p < 0.05). In clinical studies, MPI had higher specificity (66% v 43%, p < 0.05) than visual MCE and good accuracy (81%) for viability detection. It was less time consuming (3.4 (1.6) v 9.2 (2.4) minutes per image, p < 0.05) than quantitative blood flow estimation by regions of interest and increased the agreement between observers interpreting myocardial perfusion (kappa = 0.87 v kappa = 0.75, p < 0.05). MPI is useful for the evaluation of myocardial viability both in animals and in patients. It is less time consuming than quantification analysis by regions of interest and less observer dependent than visual analysis. Thus, strategies incorporating this technique may be valuable for the evaluation of myocardial viability in clinical routine.

Regional myocardial perfusion in patients with atherosclerotic coronary artery disease, at rest and during angina pectoris induced by tachycardia

International Nuclear Information System (INIS)

Maseri, A.; L'Abbate, A.; Pesola, A.; Michelassi, C.; Marzilli, M.; De Nes, M.

1977-01-01

We studied regional myocardial perfusion by scintigraphic computer-assisted analysis of initial distribution, washout rates, and residual activity of 133 Xe injected into the left coronary artery of four patients with normal arteriograms and 14 patients with coronary stenosis. At rest, residual activity in poststenotic regions was always greater than in control regions, but initial washout rates were not slower. During angina, following xenon injections, the amount of indicator distributed to the poststenotic regions was markedly reduced; the increase of the initial washout rates was smaller than in control regions relative to rest, and residual activity was higher. Initial washout rates did not differ as much as from those of normal myocardium because in severe ischemia too little indicator is deposited initially in these regions to produce a change of any magnitude. Indeed, when angina was induced immediately after the xenon injection, poststenotic washout rates became much slower during angina than at rest, a finding that implicates functional factors in impairing poststenotic myocardial perfusion during angina

Analysis of acute myocardial infarction occurance in Saratov region using GIS-technologies and prognostic modeling

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SokolovI.M.

2012-09-01

Full Text Available

The research objective: To find estimation tools of incidence of acute myocardial infarction at the regional level and to optimize organization of medical assistance to patients with acute coronary pathology. Materials. With the use of statistics of territorial distribution of acute myocardial infarction incidence in the region and GIS-TECHNOLOGIES the statistical analysis and mathematical modelling of the spatially-organizational data has been carried out. Results. On the basis of the received results the prognostic model of development of acute coronary pathology has been generated. Measures on optimization of organization of medical assistance to patients with an acute coronary pathology have been stated. Conclusion. Methods of intellectual support of the doctor may become effective in formation of organizational structure of the system of stage-by-stage qualified and specialized aid to patients with acute coronary syndrome.

The E-domain region of mechano-growth factor inhibits cellular apoptosis and preserves cardiac function during myocardial infarction.

Science.gov (United States)

Mavrommatis, Evangelos; Shioura, Krystyna M; Los, Tamara; Goldspink, Paul H

2013-09-01

Insulin-like growth factor-1 (IGF-1) isoforms are expressed via alternative splicing. Expression of the minor isoform IGF-1Eb [also known as mechano-growth factor (MGF)] is responsive to cell stress. Since IGF-1 isoforms differ in their E-domain regions, we are interested in determining the biological function of the MGF E-domain. To do so, a synthetic peptide analog was used to gain mechanistic insight into the actions of the E-domain. Treatment of H9c2 cells indicated a rapid cellular uptake mechanism that did not involve IGF-1 receptor activation but resulted in a nuclear localization. Peptide treatment inhibited the intrinsic apoptotic pathway in H9c2 cells subjected to cell stress with sorbitol by preventing the collapse of the mitochondrial membrane potential and inhibition of caspase-3 activation. Therefore, we administered the peptide at the time of myocardial infarction (MI) in mice. At 2 weeks post-MI cardiac function, gene expression and cell death were assayed. A significant decline in both systolic and diastolic function was evident in untreated mice based on PV loop analysis. Delivery of the E-peptide ameliorated the decline in function and resulted in significant preservation of cardiac contractility. Associated with these changes were an inhibition of pathologic hypertrophy and significantly fewer apoptotic nuclei in the viable myocardium of E-peptide-treated mice post-MI. We conclude that administration of the MGF E-domain peptide may provide a means of modulating local tissue IGF-1 autocrine/paracrine actions to preserve cardiac function, prevent cell death, and pathologic remodeling in the heart.

Quantitative assessment of myocardial blood flow by measurement of fractional myocardial uptake of 201Tl

International Nuclear Information System (INIS)

Yonekura, Yoshiharu; Ishii, Yasushi; Torizuka, Kanji; Kadota, Kazunori; Kambara, Hirofumi

1980-01-01

Fractional Myocardial uptake of 201 Tl was measured for the quantitative assessment of myocardial blood flow in coronary artery disease (CAD). 10 normals and 28 CAD, 7 of which have less than 50% stenosis (CAD I) and 21 of which have more than 50% stenosis (CAD II) in the proximal portion of coronary arteries, were studied at rest and with submaximal exercise loading by bicycle ergometer. After intravenous injection of 201 Tl, its rapid transport process was recorded during the initial 5 minutes by a scintillation camera and a minicomputer. Total injected dosage (T) was obtained from the counts of the entire chest region during the initial passage of the tracer through the heart and lung. Myocardial uptake (M) was counted with the same geometry from the subsequent accumulation within the myocardial region with subtraction of the background activities in the upper mediastinal region (B). The fractional myocardial uptake of 201 Tl ((M-B)/T) is assumed to be proportional to the fractional myocardial blood flow to cardiac output (MBF/CO) according to the indicator fractionation principle. The average value of MBF/CO at rest in CAD (4.11 +- 1.12%) was significantly greater than in normals (3.36 +- 0.49%), which may be caused by an increased left ventricular mass in CAD. Change rate of MBF/CO on the exercise loading was significantly less in CAD I (1.36 +- 0.14) and in CAD II (1.11 +- 0.21) than in normals (1.75 +- 0.11). MBF/CO increased proportionally to the increment of the double product of heart rate and systolic blood pressure by exercise loading in normals, whereas it didn't in CAD. The sensitivity of this method was superior to the stress electrocardiogram and the stress myocardial perfusion imaging, not only in CAD II but also in CAD I. This result indicated that this type of global assessment of the myocardial reserve capacity is valuable in addition to the simple stress myocardial perfusion imaging. (author)

Lebetin 2, a Snake Venom-Derived Natriuretic Peptide, Attenuates Acute Myocardial Ischemic Injury through the Modulation of Mitochondrial Permeability Transition Pore at the Time of Reperfusion.

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Bochra Tourki

Full Text Available Cardiac ischemia is one of the leading causes of death worldwide. It is now well established that natriuretic peptides can attenuate the development of irreversible ischemic injury during myocardial infarction. Lebetin 2 (L2 is a new discovered peptide isolated from Macrovipera lebetina venom with structural similarity to B-type natriuretic peptide (BNP. Our objectives were to define the acute cardioprotective actions of L2 in isolated Langendorff-perfused rat hearts after regional or global ischemia-reperfusion (IR. We studied infarct size, left ventricular contractile recovery, survival protein kinases and mitochondrial permeability transition pore (mPTP opening in injured myocardium. L2 dosage was determined by preliminary experiments at its ability to induce cyclic guanosine monophosphate (cGMP release without changing hemodynamic effects in normoxic hearts. L2 was found to be as effective as BNP in reducing infarct size after the induction of either regional or global IR. Both peptides equally improved contractile recovery after regional IR, but only L2 increased coronary flow and reduced severe contractile dysfunction after global ischemia. Cardioprotection afforded by L2 was abolished after isatin or 5-hydroxydecanote pretreatment suggesting the involvement of natriuretic peptide receptors and mitochondrial KATP (mitoKATP channels in the L2-induced effects. L2 also increased survival protein expression in the reperfused myocardium as evidenced by phosphorylation of signaling pathways PKCε/ERK/GSK3β and PI3K/Akt/eNOS. IR induced mitochondrial pore opening, but this effect was markedly prevented by L2 treatment. These data show that L2 has strong cardioprotective effect in acute ischemia through stimulation of natriuretic peptide receptors. These beneficial effects are mediated, at least in part, by mitoKATP channel opening and downstream activated survival kinases, thus delaying mPTP opening and improving IR-induced mitochondrial

Quantitative aspects of myocardial perfusion imaging

International Nuclear Information System (INIS)

Vogel, R.A.

1980-01-01

Myocardial perfusion measurements have traditionally been performed in a quantitative fashion using application of the Sapirstein, Fick, Kety-Schmidt, or compartmental analysis principles. Although global myocardial blood flow measurements have not proven clinically useful, regional determinations have substantially advanced our understanding of and ability to detect myocardial ischemia. With the introduction of thallium-201, such studies have become widely available, although these have generally undergone qualitative evaluation. Using computer-digitized data, several methods for the quantification of myocardial perfusion images have been introduced. These include orthogonal and polar coordinate systems and anatomically oriented region of interest segmentation. Statistical ranges of normal and time-activity analyses have been applied to these data, resulting in objective and reproducible means of data evaluation

Cell stiffness, contractile stress and the role of extracellular matrix

International Nuclear Information System (INIS)

An, Steven S.; Kim, Jina; Ahn, Kwangmi; Trepat, Xavier; Drake, Kenneth J.; Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne; Fredberg, Jeffrey J.; Biswal, Shyam

2009-01-01

Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses.

Cell stiffness, contractile stress and the role of extracellular matrix

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An, Steven S., E-mail: san@jhsph.edu [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Kim, Jina [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Ahn, Kwangmi [Division of Biostatistics, Penn State College of Medicine, Hershey, PA 17033 (United States); Trepat, Xavier [CIBER, Enfermedades Respiratorias, 07110 Bunyola (Spain); Drake, Kenneth J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Fredberg, Jeffrey J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Biswal, Shyam [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205 (United States)

2009-05-15

Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses.

Myocardial ischemia and angina pectoris

International Nuclear Information System (INIS)

Selwyn, A.P.; Fox, K.M.; Jonathan, A.; Lavender, P.; Watson, I.

1981-01-01

Ambulatory monitoring of ST segment changes was performed in 60 patients presenting with angina, positive ECG stress tests and coronary artery disease, 85% of ischemic ECG events were asymptomatic, 37% occurred with no increase in heart rate and 15% of episodes either lasted 20 minutes or more or fluctuated in severity. A controlled pilot study in ten patients showed depression. Radionuclide studies in 50 patients with angina and coronary artery disease have shown that stress (i.e., atrial pacing) produced different patterns of disturbed regional myocardial perfusion related to the patient's exercise capacity and eventually leading to a decrease in regional myocardial perfusion during the ischemic episode. ST segment depression appeared only after the decrease in regional myocardial perfusion. These findings combined with past research suggest that patients with angina and coronary artery disease can suffer frequent asymptomatic disturbances of the regional myocardial perfusion. The frequency of these episodes and the time course for the recovery of the metabolic consequences mean that segments of ventricular myocardium may be constantly abnormal. The relative importance of changes in coronary tone and malfunction of platelets in the diseased coronary tree needs to be examined in clinical research. Pilot studies of antiplatelet agents have shown a significant beneficial effect on episodes of ischemia occurring at night and those occurring without any increase in heart rate. The techniques and observations in these patients with coronary artery disease all suggest that acute transient regional myocardial ischemia is caused by a variety of mechnisms. Further research using objective methods is required to discover the causes of ischemia and to rationalize treatment. (orig./MG) [de

Correlation between myocardial Thallium-201 kinetics, myocardial lactate metabolism and coronary angiographic findings in hypertrophic cardiomyopathy

International Nuclear Information System (INIS)

Hanrath, P.; Mathey, D.; Thiel, U.; Kupper, W.; Bleifeld, W.; Mantz, R.; Vorbringer, H.; Schneider, C.

1980-01-01

In 20 patients with idiopathic hypertrophic obstructive and nonobstructive cardiomyopathy (IHSS), biphasic Thallium-201 myocardial scintigraphy was performed. Regional myocardial Thallium-201 kinetics of these patients were analysed by a semiquantitative computerized method and compared with those of 6 normal subjects. In 12 of 18 with IHSS and no coronary artery disease 26 regions of interest with irreversible and 6 regions of interest with reversible Thallium-201 defects could be detected. Most of the Thallium-201 defects were localized in the interventricular septum. The defects were not related to the age of the patients and there was no relationship between the occurence of reversible Thallium-201 defects and pathological myocardial lactate extraction rate during maximal atrial pacing measured in 14 patients. The percentage (6.8%) of irreversible defect regions in patients with LV outflow obstruction at rest (n = 13) was more than twice higher compared to those (n = 5, 3.2%) without LV outflow obstruction or no provocative pressure gradient, resp. These data suggest that IHSS often associated with regional ischemic myocardial fibrosis despite normal coronary arteries. Therefore in these patients Thallium scintigraphy cannot be used as a noninvasive screening method to exclude or prove coronary artery disease. (orig.) [de

Assessment of regional myocardial blood flow with N-13 ammonia PET

International Nuclear Information System (INIS)

Himi, Toshiharu

1992-01-01

Regional myocardial blood flow (RMBF) has been assessed with O-15 water, O-15 CO 2 and N-13 ammonia in Japan, and O-15 water has been used most commonly for quantitative measurement of RMBF with Iida's method. Though myocardial image quality with N-13 ammonia is superior to that with O-15 water or that with O-15 CO 2 , RMBF was not assessed quantitatively with N-13 ammonia. We have attempted to assess RMBF non-invasively with N-13 ammonia and dynamic PET. Yoshida et. al applied the first-pass flow model to N-13 ammonia dynamic PET for measurement of RMBF. We could measure RMBF of the patients with hypertrophic cardiomyopathy (HCM) and could assess effects of vaso-dilating agents on RMBF non-invasively with this method. But this method dose not take account of cross-contamination of recorded counts between myocardium and surrounding tissues, and hence we have applied factor analysis to dynamic PET for correction of that. It was suggested that cross-contamination in normal cases could be corrected by the factor analysis and there were few cross-contamination in the patients with HCM. (author)

Coronary wave energy: a novel predictor of functional recovery after myocardial infarction.

Science.gov (United States)

De Silva, Kalpa; Foster, Paul; Guilcher, Antoine; Bandara, Asela; Jogiya, Roy; Lockie, Tim; Chowiencyzk, Phil; Nagel, Eike; Marber, Michael; Redwood, Simon; Plein, Sven; Perera, Divaka

2013-04-01

Revascularization after acute coronary syndromes provides prognostic benefit, provided that the subtended myocardium is viable. The microcirculation and contractility of the subtended myocardium affect propagation of coronary flow, which can be characterized by wave intensity analysis. The study objective was to determine in acute coronary syndromes whether early wave intensity analysis-derived microcirculatory (backward) expansion wave energy predicts late viability, defined by functional recovery. Thirty-one patients (58±11 years) were enrolled after non-ST elevation myocardial infarction. Regional left ventricular function and late-gadolinium enhancement were assessed by cardiac magnetic resonance imaging, before and 3 months after revascularization. The backward-traveling (microcirculatory) expansion wave was derived from wave intensity analysis of phasic coronary pressure and velocity in the infarct-related artery, whereas mean values were used to calculate hyperemic microvascular resistance. Twelve-hour troponin T, left ventricular ejection fraction, and percentage late-gadolinium enhancement mass were 1.35±1.21 µg/L, 56±11%, and 8.4±6.0%, respectively. The infarct-related artery backward-traveling (microcirculatory) expansion wave was inversely correlated with late-gadolinium enhancement infarct mass (r=-0.81; Pwave threshold of 2.8 W m(-2) s(-2)×10(5) predicted functional recovery with sensitivity and specificity of 0.91 and 0.82 (AUC 0.88). Hyperemic microvascular resistance correlated with late-gadolinium enhancement mass (r=0.48; P=0.03) but not left ventricular recovery (r=-0.34; P=0.07). The microcirculation-derived backward expansion wave is a new index that correlates with the magnitude and location of infarction, which may allow for the prediction of functional myocardial recovery. Coronary wave intensity analysis may facilitate myocardial viability assessment during cardiac catheterization.

Simultaneous estimates of regional myocardial blood flow and metabolism by the developing chick heart using [201]thallium and [14C] 2-deoxyglucose autoradiography

International Nuclear Information System (INIS)

Kostreva, D.R.; Wood, J.D.

1990-01-01

Little is known about regional myocardial blood flow and metabolism in the developing heart. Simultaneous estimates of regional myocardial blood flow and glucose metabolism have been made in the adult rat by Yonekura et al using [ 201 ] Thallium (THAL) and [ 14 C]2-deoxyglucose (DG) autoradiography. Since glucose is the primary cardiac metabolic substrate during development, glucose utilization is also an estimate of myocardial metabolism. Examination and comparison of the THAL and DG autoradiographs revealed that there is an uncoupling of blood flow and metabolism in the developing chick heart. Areas of the heart which had marked glucose utilization did not always have marked blood flow. Regions of the heart which had marked blood flow but very little glucose utilization were the interventricular septum and the apex. One explanation for this disparity is that although blood flow may be established in these regions, normal cardiac function requiring significant substrate utilization may not be fully developed

Assessment of myocardial perfusion and metabolism for assessment of myocardial viability

International Nuclear Information System (INIS)

Beller, G.

1996-01-01

Identifying preserved myocardial viability in the presence of severe regional left ventricular dysfunction is becoming increasingly more important for clinical decision-making to better select those patients with coronary artery disease who will benefit most from revascularization. 201 Tl remains the most commonly employed radionuclide for detecting both ischemia and viability. A severe persistent defect with 201 Tl uptake compared to peak to improved perfusion and corresponding improved function after revascularisation. Detection of defect reversibility on 201 Tl imaging is enhanced by 'reinjection' of a second 201 Tl dose after acquisition of redistribution images. Initial and 4-hour rest/redistribution imaging has proven most usefull for detection of viability in the resting state in patients with ischemic cardiomyopathy. The greater the extent of preoperative viability, the greater is the improvement in regional and global function after revascularisation. 99 Tc sestamibi has also been demonstrated to be extracted by myocardial cells in proportion to regional blood flow in the presence of viable myocities. Although this agrnt does not redistribute after intravenous injection, its >50% uptake of the tracer implies viablility and predicts improved regional function after revascularisation. Finally positron emission tomography with 18 F fluorodeoxoglucose (FDG) is perhaps the most sensitive noninvasive imaging technique for detection of viability in stunned or hibernating myocardium. A mismatch pattern between regional flow and FDG uptake as approximately an 80-85% positive preicted value for predicting improved function in asynergic myocardial regions after revascualarisation

Effects of rapid digitalization on total and regional myocardial performance in patients with coronary artery disease.

Science.gov (United States)

Ferlinz, J; DelVicario, M; Aronow, W S

1978-09-01

In order to evaluate the effects of rapid digitalization on LV volumes, ejection fraction, and asynergy, 21 patients without heart failure were studied with a combination of hemodynamic and angiographic techniques before and after administration of intravenous ouabain (0.007 mg./Kg.). Seven patients had no CAD and served as normal (control) subjects (Group I), while 14 patients had extensive coronary disease (Group II). All pre-ouabain parameters were within the normal limits in Group I. After ouabain infusion, all indices of LV contractility: dP/dt, VCF, and ejection fraction rose significantly in the normal group, while LV filling pressure and end-diastolic volume remained unchanged. The baseline hemodynamic and volumetric values for Group II patients corresponded closely to their normal (Group I) counterparts, and exhibited similar changes after ouabain administration. Eight patients in Group II also had regional disorders of LV contractility, delineated by 23 abnormal hemiaxes of shortening. After ouabain, 15 out of 23 asynergic segments (65 per cent) improved, seven remained unchanged, and one worsened. It is therefore concluded that rapid digitalization not only enhances LV performance in normal subjects and in patients with CAD, but can also markedly reduce the extent of LV asynergy.

Mast cells regulate myofilament calcium sensitization and heart function after myocardial infarction.

Science.gov (United States)

Ngkelo, Anta; Richart, Adèle; Kirk, Jonathan A; Bonnin, Philippe; Vilar, Jose; Lemitre, Mathilde; Marck, Pauline; Branchereau, Maxime; Le Gall, Sylvain; Renault, Nisa; Guerin, Coralie; Ranek, Mark J; Kervadec, Anaïs; Danelli, Luca; Gautier, Gregory; Blank, Ulrich; Launay, Pierre; Camerer, Eric; Bruneval, Patrick; Menasche, Philippe; Heymes, Christophe; Luche, Elodie; Casteilla, Louis; Cousin, Béatrice; Rodewald, Hans-Reimer; Kass, David A; Silvestre, Jean-Sébastien

2016-06-27

Acute myocardial infarction (MI) is a severe ischemic disease responsible for heart failure and sudden death. Inflammatory cells orchestrate postischemic cardiac remodeling after MI. Studies using mice with defective mast/stem cell growth factor receptor c-Kit have suggested key roles for mast cells (MCs) in postischemic cardiac remodeling. Because c-Kit mutations affect multiple cell types of both immune and nonimmune origin, we addressed the impact of MCs on cardiac function after MI, using the c-Kit-independent MC-deficient (Cpa3(Cre/+)) mice. In response to MI, MC progenitors originated primarily from white adipose tissue, infiltrated the heart, and differentiated into mature MCs. MC deficiency led to reduced postischemic cardiac function and depressed cardiomyocyte contractility caused by myofilament Ca(2+) desensitization. This effect correlated with increased protein kinase A (PKA) activity and hyperphosphorylation of its targets, troponin I and myosin-binding protein C. MC-specific tryptase was identified to regulate PKA activity in cardiomyocytes via protease-activated receptor 2 proteolysis. This work reveals a novel function for cardiac MCs modulating cardiomyocyte contractility via alteration of PKA-regulated force-Ca(2+) interactions in response to MI. Identification of this MC-cardiomyocyte cross-talk provides new insights on the cellular and molecular mechanisms regulating the cardiac contractile machinery and a novel platform for therapeutically addressable regulators. ©2016 Ngkelo et al.

Myocardial imaging with thallium-201: an experimental model for analysis of the true myocardial and background image components

International Nuclear Information System (INIS)

Narahara, K.A.; Hamilton, G.W.; Williams, D.L.; Gould, K.L.

1977-01-01

The true myocardial and background components of a resting thallium-201 myocardial image were determined in an experimental dog model. True background was determined by imaging after the heart had been removed and replaced with a water-filled balloon of equal size and shape. In all studies, the background estimated from the region surrounding the heart exceeded true background activity. Furthermore, the relationship between true myocardial background and that estimated from the pericardiac region was inconsistent. Background estimates based on the activity surrounding the heart were not accurate predictors of true background activity

Subacute ghrelin administration inhibits apoptosis and improves ultrastructural abnormalities in remote myocardium post-myocardial infarction.

Science.gov (United States)

Eid, Refaat A; Zaki, Mohamed Samir Ahmed; Al-Shraim, Mubarak; Eleawa, Samy M; El-Kott, Attalla Farag; Al-Hashem, Fahaid H; Eldeen, Muhammad Alaa; Ibrahim, Hoja; Aldera, Hussain; Alkhateeb, Mahmoud A

2018-05-01

This study investigated the effect of ghrelin on cardiomyocytes function, apoptosis and ultra-structural alterations of remote myocardium of the left ventricle (LV) of rats, 21 days post myocardial infarction (MI). Rats were divided into 4 groups as a control, a sham-operated rats, a sham-operated+ghrelin, an MI + vehicle and an MI + ghrelin-treated rats. MI was induced by LAD ligation and then rats were recievd a concomitant doe of either normal saline as a vehicle or treated with ghrelin (100 μg/kg S.C., 2x/day) for 21 consecutive days. Ghrelin enhanced myocardial contractility in control rats and reversed the decreases in myocardial contractility and the increases in the serum levels of CK-MB and LDH in MI-induced rats. Additionally, it inhibited the increases in levels of Bax and cleaved caspase 3 and increased those for Bcl-2 in the remote myocardium of rat's LV, post-MI. At ultra-structural level, while ghrelin has no adverse effects on LV myocardium obtained from control or sham-treated rats, ghrelin post-administration to MI-induced rats reduced vascular formation, restored normal microfilaments appearance and organization, preserved mitochondria structure, and prevented mitochondrial swelling, collagen deposition and number of ghost bodies in the remote areas of their LV. Concomitantly, in remote myocardium of MI-induced rats, ghrelin enhanced endoplasmic reticulum intracellular organelles count, decreased number of atrophied nuclei and phagocytes, diminished the irregularity in the nuclear membranes and inhibited chromatin condensation. In conclusion, in addition to the physiological, biochemical and molecular evidence provided, this is the first study that confirms the anti-apoptotic effect of ghrelin in the remote myocardium of the LV during late MI at the level of ultra-structural changes. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Paradoxical hypotension during dobutamine infusion for myocardial perfusion scintigraphy

International Nuclear Information System (INIS)

Erguen, E.L.; Caner, B.; Atalar, E.; Karanfil, A.; Tokgoezoglu, L.

1998-01-01

Dobutamine as a predominant beta-1 agonist increases heart rate and myocardial contractility and at sufficient high doses, it also increases systolic blood pressure. This study was undertaken to describe instances of paradoxical hypotension during dobutamine infusion for Tl-201 myocardial perfusion SPECT study and the relationship between scintigraphic findings and hypotension occurred during dobutamine infusion. Methods: In 201 consecutive patients unable to perform adequate exercise, dobutamine Tl-201 myocardial SPECT was performed. Dobutamine was infused starting from 10 μg/kg/min increasing to 40 μ/kg/min. Paradoxical hypotension was defined as a decrease in systolic blood pressure ≥ 20 mmHg compared with baseline study. Paradoxical hypotension was observed in 40 patients (Group A) out of 201 (19.9%) while no significant change in systolic blood pressure was detected in the remaining 161 patients (Group B). Mean maximum fall in systolic blood pressure was 39±18 mmHg (range: 20-90). In 33 of 40 patients (83%) with paradoxical hypotension, scintigraphy was normal compared to 131 (81%) of the remaining 161 patients. In patients of Group A, angiography, echocardiography and tilt table tests were performed in 13, 11 and 6 patients respectively. Nine of 13 angiographic evaluations (69%), 10 of 11 echocardiographic evaluations (91%), all of the tilt table tests were normal. Additionally, all of the patients of Group A were clinically followed up at least 6 months after the myocardial perfusion scintigraphy. None of the patients had a cardiac event except one patient during the follow-up period. Conclusion: Paradoxical hypotension during dobutamine infusion for myocardial scintigraphy is not an uncommon finding and up to 19.9% patients may develop such hypotension. To maximize test safety, precautions should be taken during dobutamine myocardial stress test, since remarkable decrease in systolic blood pressure may occur. Unlike hypotension occurring with exercise

Contractile injection systems of bacteriophages and related systems

DEFF Research Database (Denmark)

Taylor, Nicholas M I; van Raaij, Mark J; Leiman, Petr G

2018-01-01

Contractile tail bacteriophages, or myobacteriophages, use a sophisticated biomolecular structure to inject their genome into the bacterial host cell. This structure consists of a contractile sheath enveloping a rigid tube that is sharpened by a spike-shaped protein complex at its tip. The spike ...

Noninvasive determination of myocardial blood flow, oxygen consumption and efficiency in normal humans by carbon-11 acetate positron emission tomography imaging

International Nuclear Information System (INIS)

Porenta, G.; Cherry, S.; Czernin, J.; Brunken, R.; Kuhle, W.; Hashimoto, T.; Schelbert, H.R.

1999-01-01

The aims of this study were: (1) to measure noninvasively and near simultaneously myocardial blood flow, oxygen consumption, and contractile function and (2) to analyze myocardial energy expenditure and efficiency at rest and during dobutamine stress in normal humans. Dynamic and gated carbon-11 acetate positron emission tomography (PET) imaging was performed in 11 normal subjects. The initial uptake of 11 C-acetate was measured to estimate myocardial blood flow. Oxygen consumption was derived from the monoexponential slope of the 11 C-clearance curve recorded during myocardial washout. ECG-gated systolic and diastolic images were acquired during the peak myocardial 11 C activity to measure left ventricular radius, myocardial wall thickness, and long axis length. Myocardial oxygen consumption and parameters of cardiac geometry were used to determine myocardial energetics and cardiac efficiency by tension-area area analysis. Myocardial blood flow averaged 0.8±0.06 ml min -1 g -1 at rest and 1.48±0.15 ml min -1 g -1 during dobutamine stress. Oxygen delivery and consumption were 151±13 and 88±15 μl O 2 min -1 g -1 at rest and increased to 291±31 and 216±31 μl O 2 min -1 g -1 , respectively, during pharmacological stress (P 11 C acetate imaging provides the unique capability to study noninvasively determinants of myocardial energy delivery, expenditure, and efficiency. (orig.)

Effect of prophylactic digitalization on the development of myocardial hypertrophy.

Science.gov (United States)

Cutilletta, A F; Rudnik, M; Arcilla, R A; Straube, R

1977-11-01

The effect of prophylactic digitalization on the development of left ventricular hypertrophy was studied in adult rats. Digitoxin, 0.1 mg/100 g body wt or solvent was given daily for 1 wk prior to either aortic constriction or sham operation and was continued until the animals were killed, either 1 or 4 wk after surgery. A hemodynamic study was done in those animals killed 1 wk after surgery; hearts of all animals were examined for evidence of myocardial hypertrophy. Constriction of the ascending aorta had no significant effect on cardiac output but did reduce peak flow velocity and flow acceleration. An increase in left ventricular mass, RNA, and hydroxyproline was found in the animals with aortic constriction. Digitoxin treatment did not alter peak flow velocity or flow acceleration, but did significantly increase isovolumic (dP/dt)P-1. Digitoxin had no effect on body weight, heart weight, RNA, or hydroxyproline in either the sham-operated animals or in the animals with aortic constriction. Therefore, despite plasma digitoxin levels sufficient to affect myocardial contractility, left ventricular hypertrophy still developed after aortic constriction.

Repeatability of regional myocardial blood flow calculation in 82Rb PET imaging

International Nuclear Information System (INIS)

Knešaurek, Karin; Machac, Josef; Zhang, Zhuangyu

2009-01-01

We evaluated the repeatability of the calculation of myocardial blood flow (MBF) at rest and pharmacological stress, and calculated the coronary flow reserve (CFR) utilizing 82 Rb PET imaging. The aim of the research was to prove high repeatability for global MBF and CFR values and good repeatability for regional MBF and CFR values. The results will have significant impact on cardiac PET imaging in terms of making it more affordable and increasing its use. 12 normal volunteers were imaged at rest and during pharmacological stress, with 2220 MBq of 82 Rb each. A GE Advance PET system was used to acquire dynamic 50-frame studies. MBF was calculated with a 2-compartmental model using a modified PMOD program (PMOD; University Hospital Zurich, Zurich, Switzerland). Two differential equations, describing a 2-compartmental model, were solved by numerical integration and using Levenberg-Marquardt's method for fitting data. The PMOD program defines 16 standard segments and calculates myocardial flow for each segment, as well as average septal, anterior, lateral, inferior and global flow. Repeatability was evaluated according to the method of Bland and Altman. Global rest and stress MBF, as well as global CFR, showed very good repeatability. No significant differences were found between the paired resting global MBF (0.63 ± 0.13 vs. 0.64 ± 0.13 mL/min/g; mean difference, -1.0% ± 2.6%) and the stress global MBF (1.37 ± 0.23 vs. 1.37 ± 0.24; mean difference, 0.1% ± 2.3%). Global CFR was highly reproducible (2.25 ± 0.56 vs. 2.22 ± 0.54, P = not statistically significant; mean difference, 1.3% ± 14.3%). Repeatability coefficients for global rest MBF were 0.033 (5.2%) and stress MBF 0.062 (4.5%) mL/min/g. Regional rest and stress MBF and CFR have shown good reproducibility. The average per sector repeatability coefficients for rest MBF were 0.056 (8.5%) and stress MBF 0.089 (6.3%) mL/min/g, and average repeatability coefficient for CFR was 0.25 (10.6%). The results

Theoretical considerations in measurement of time discrepancies between input and myocardial time-signal intensity curves in estimates of regional myocardial perfusion with first-pass contrast-enhanced MRI.

Science.gov (United States)

Natsume, Takahiro; Ishida, Masaki; Kitagawa, Kakuya; Nagata, Motonori; Sakuma, Hajime; Ichihara, Takashi

2015-11-01

The purpose of this study was to develop a method to determine time discrepancies between input and myocardial time-signal intensity (TSI) curves for accurate estimation of myocardial perfusion with first-pass contrast-enhanced MRI. Estimation of myocardial perfusion with contrast-enhanced MRI using kinetic models requires faithful recording of contrast content in the blood and myocardium. Typically, the arterial input function (AIF) is obtained by setting a region of interest in the left ventricular cavity. However, there is a small delay between the AIF and the myocardial curves, and such time discrepancies can lead to errors in flow estimation using Patlak plot analysis. In this study, the time discrepancies between the arterial TSI curve and the myocardial tissue TSI curve were estimated based on the compartment model. In the early phase after the arrival of the contrast agent in the myocardium, the relationship between rate constant K1 and the concentrations of Gd-DTPA contrast agent in the myocardium and arterial blood (LV blood) can be described by the equation K1={dCmyo(tpeak)/dt}/Ca(tpeak), where Cmyo(t) and Ca(t) are the relative concentrations of Gd-DTPA contrast agent in the myocardium and in the LV blood, respectively, and tpeak is the time corresponding to the peak of Ca(t). In the ideal case, the time corresponding to the maximum upslope of Cmyo(t), tmax, is equal to tpeak. In practice, however, there is a small difference in the arrival times of the contrast agent into the LV and into the myocardium. This difference was estimated to correspond to the difference between tpeak and tmax. The magnitudes of such time discrepancies and the effectiveness of the correction for these time discrepancies were measured in 18 subjects who underwent myocardial perfusion MRI under rest and stress conditions. The effects of the time discrepancies could be corrected effectively in the myocardial perfusion estimates. Copyright © 2015 Elsevier Inc. All rights

Reversible myocardial ischaemia or irreversible myocardial fibrosis

International Nuclear Information System (INIS)

Mathey, D.; Hanrath, P.; Kupper, W.; Bleifeld, W.; Montz, R.; Knop, J.; Stritzke, P.; Kroeger, E.; Bleese, N.

1978-01-01

The results of biphasis 201 thallium ( 201 Tl) scanning were compared with those of coronary arteriography, left ventricular angiography and stress ECG in 56 patients with coronary artery disease and six with no evidence of heart disease. There were 104 201 Tl defects, 50 of them reversible. The defects were always located in the area supplied by a critically stenotic coronary artery. Correlation of regional wall motion with 201 Tl activity demonstrated that in all forms of abnormal wall motion there was either ischaemia or fibrosis. The resting LV angiogram thus does not make it possible to distinguish between myocardial ischaemia and fibrosis. Taking the LV angiogram as a standard, the rate of false-positive 201 Tl scintigrams was 5%, that of false-negative ones 23%. The biphasic 201 Tl scintigram was more sensitive than the stress ECG in detecting myocardial ischaemia. It furthermore made it possible to localize the ischaemic (or fibrotic) region within the LV and to estimate its size. (orig.) [de

Apelin and APJ orchestrate complex tissue-specific control of cardiomyocyte hypertrophy and contractility in the hypertrophy-heart failure transition.

Science.gov (United States)

Parikh, Victoria Nicole; Liu, Jing; Shang, Ching; Woods, Christopher; Chang, Alex Chia Yu; Zhao, Mingming; Charo, David N; Grunwald, Zachary; Huang, Yong; Seo, Kinya; Tsao, Philip S; Bernstein, Daniel; Ruiz-Lozano, Pilar; Quertermous, Thomas; Ashley, Euan A

2018-05-18

The G protein coupled receptor APJ is a promising therapeutic target for heart failure. Constitutive deletion of APJ in the mouse is protective against the hypertrophy-heart failure transition via elimination of ligand-independent, β-arrestin dependent stretch transduction. However, the cellular origin of this stretch transduction and the details of its interaction with apelin signaling remain unknown. We generated mice with conditional elimination of APJ in the endothelium (APJ endo-/- ) and myocardium (APJ myo-/- ). No baseline difference was observed in LV function in APJ endo-/- , APJ myo-/- or controls (APJ endo+/+ , APJ myo+/+ ). After exposure to transaortic constriction (TAC), APJ endo-/- animals developed left ventricular failure while APJ myo-/- were protected. At the cellular level, carbon fiber stretch of freshly isolated single cardiomyocytes demonstrated decreased contractile response to stretch in APJ -/- cardiomyocytes compared to APJ +/+ cardiomyocytes. Calcium transient did not change with stretch in either APJ -/- or APJ +/+ cardiomyocytes. Application of apelin to APJ +/+ cardiomyocytes resulted in decreased calcium transient. Further, hearts of mice treated with apelin exhibited decreased phosphorylation at Troponin I (cTnI) N-terminal residues (Ser 22,23), consistent with increased calcium sensitivity. These data establish that APJ stretch transduction is mediated specifically by myocardial APJ, that APJ is necessary for stretch-induced increases in contractility, and that apelin opposes APJ's stretch-mediated hypertrophy signaling by lowering calcium transient while maintaining contractility through myofilament calcium sensitization. These findings underscore apelin's unique potential as a therapeutic agent that can simultaneously support cardiac function and protect against the hypertrophy-heart failure transition.

Permanently Hypoxic Cell Culture Yields Rat Bone Marrow Mesenchymal Cells with Higher Therapeutic Potential in the Treatment of Chronic Myocardial Infarction

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Yihua Liu

2017-11-01

Full Text Available Background: The mismatch between traditional in vitro cell culture conditions and targeted chronic hypoxic myocardial tissue could potentially hamper the therapeutic effects of implanted bone marrow mesenchymal stem cells (BMSCs. This study sought to address (i the extent of change to BMSC biological characteristics in different in vitro culture conditions and (ii the effectiveness of permanent hypoxic culture for cell therapy in treating chronic myocardial infarction (MI in rats. Methods: rat BMSCs were harvested and cultured in normoxic (21% O2, n=27 or hypoxic conditions (5% O2, n=27 until Passage 4 (P4. Cell growth tests, flow cytometry, and Bio-Plex assays were conducted to explore variations in the cell proliferation, phenotype, and cytokine expression, respectively. In the in vivo set-up, P3-BMSCs cultured in normoxia (n=6 or hypoxia (n=6 were intramyocardially injected into rat hearts that had previously experienced 1-month-old MI. The impact of cell therapy on cardiac segmental viability and hemodynamic performance was assessed 1 month later by 2-Deoxy-2[18F]fluoro-D-glucose (18F-FDG positron emission tomography (PET imaging and pressure-volume catheter, respectively. Additional histomorphological examinations were conducted to evaluate inflammation, fibrosis, and neovascularization. Results: Hypoxic preconditioning significantly enhanced rat BMSC clonogenic potential and proliferation without altering the multipotency. Different profiles of inflammatory, fibrotic, and angiogenic cytokine secretion were also documented, with a marked correlation observed between in vitro and in vivo proangiogenic cytokine expression and tissue neovessels. Hypoxic-preconditioned cells presented a beneficial effect on the myocardial viability of infarct segments and intrinsic contractility. Conclusion: Hypoxic-preconditioned BMSCs were able to benefit myocardial perfusion and contractility, probably by modulating the inflammation and promoting

Permanently Hypoxic Cell Culture Yields Rat Bone Marrow Mesenchymal Cells with Higher Therapeutic Potential in the Treatment of Chronic Myocardial Infarction.

Science.gov (United States)

Liu, Yihua; Yang, Xiaoxi; Maureira, Pablo; Falanga, Aude; Marie, Vanessa; Gauchotte, Guillaume; Poussier, Sylvain; Groubatch, Frederique; Marie, Pierre-Yves; Tran, Nguyen

2017-01-01

The mismatch between traditional in vitro cell culture conditions and targeted chronic hypoxic myocardial tissue could potentially hamper the therapeutic effects of implanted bone marrow mesenchymal stem cells (BMSCs). This study sought to address (i) the extent of change to BMSC biological characteristics in different in vitro culture conditions and (ii) the effectiveness of permanent hypoxic culture for cell therapy in treating chronic myocardial infarction (MI) in rats. rat BMSCs were harvested and cultured in normoxic (21% O2, n=27) or hypoxic conditions (5% O2, n=27) until Passage 4 (P4). Cell growth tests, flow cytometry, and Bio-Plex assays were conducted to explore variations in the cell proliferation, phenotype, and cytokine expression, respectively. In the in vivo set-up, P3-BMSCs cultured in normoxia (n=6) or hypoxia (n=6) were intramyocardially injected into rat hearts that had previously experienced 1-month-old MI. The impact of cell therapy on cardiac segmental viability and hemodynamic performance was assessed 1 month later by 2-Deoxy-2[18F]fluoro-D-glucose (18F-FDG) positron emission tomography (PET) imaging and pressure-volume catheter, respectively. Additional histomorphological examinations were conducted to evaluate inflammation, fibrosis, and neovascularization. Hypoxic preconditioning significantly enhanced rat BMSC clonogenic potential and proliferation without altering the multipotency. Different profiles of inflammatory, fibrotic, and angiogenic cytokine secretion were also documented, with a marked correlation observed between in vitro and in vivo proangiogenic cytokine expression and tissue neovessels. Hypoxic-preconditioned cells presented a beneficial effect on the myocardial viability of infarct segments and intrinsic contractility. Hypoxic-preconditioned BMSCs were able to benefit myocardial perfusion and contractility, probably by modulating the inflammation and promoting angiogenesis. © 2017 The Author(s). Published by S. Karger AG

Criteria for definition of regional functional improvement on quantitative post-stress gated myocardial SPET after bypass surgery in patients with ischaemic cardiomyopathy

International Nuclear Information System (INIS)

Lee, Dong Soo; Cheon, Gi Jeong; Paeng, Jin Chul; Chung, June-Key; Lee, Myung Chul; Kim, Ki Bong

2002-01-01

Myocardial viability can be defined as functional improvement of dysfunctional myocardium after revascularization. The purpose of this study was to define the optimal criteria for definition of regional functional improvement after coronary artery bypass graft (CABG) surgery on quantitative gated single-photon emission tomography (SPET). Thirty-two patients (26 men, 6 women; age 56±13 years) with coronary artery disease (three-vessel disease, 17; two-vessel disease, 15; previous history of myocardial infarction, 9) and severe left ventricular dysfunction (LVEF≤35%) underwent CABG. Rest thallium-201/dipyridamole stress technetium-99m methoxyisobutylisonitrile gated myocardial SPET was performed before and 3 months after CABG. Global LV functional improvement was defined as either an improvement in LVEF of 10% (n=15) or an improvement in LVEF of 5% combined with a decrease in end-systolic volume of 10 ml (n=2) after CABG on quantitative gated SPET. Postoperative regional wall thickening improvement (ΔRWT), regional wall motion improvement (ΔRWM) and regional resting (ΔRP) and stress perfusion improvement (ΔRstrP) were used to determine global functional improvement by ROC curve analysis, and the optimal criteria for definition of viable regional dysfunctional myocardium were defined on the ROC curves. Correlations were verified by determining the number of improved myocardial regions and LVEF improvement. LVEF was improved from 25%±6% to 34%±11% after CABG. A total of 229 segments were dysfunctional (wall motion ≤2 mm, thickening ≤20%) before CABG. On ROC curve analysis using global functional improvement as an indicator of viability, the areas under the ROC curves (AUCs) of ΔRWT and ΔRWM were 0.717 and 0.620, respectively. The AUC of ΔRWT was significantly larger than that of ΔRWM (P=0.009) and the optimal cut-off value of ΔRWT was 15%. The AUCs of ΔRP and ΔRstrP were not significant. The correlation coefficients between summed ΔRWT and �

Investigating Cardiac MRI Based Right Ventricular Contractility As A Novel Non-Invasive Metric of Pulmonary Arterial Pressure

Science.gov (United States)

Menon, Prahlad G; Adhypak, Srilakshmi M; Williams, Ronald B; Doyle, Mark; Biederman, Robert WW

2014-01-01

BACKGROUND We test the hypothesis that cardiac magnetic resonance (CMR) imaging-based indices of four-dimensional (4D) (three dimensions (3D) + time) right ventricle (RV) function have predictive values in ascertaining invasive pulmonary arterial systolic pressure (PASP) measurements from right heart catheterization (RHC) in patients with pulmonary arterial hypertension (PAH). METHODS We studied five patients with idiopathic PAH and two age and sex-matched controls for RV function using a novel contractility index (CI) for amplitude and phase to peak contraction established from analysis of regional shape variation in the RV endocardium over 20 cardiac phases, segmented from CMR images in multiple orientations. RESULTS The amplitude of RV contractility correlated inversely with RV ejection fraction (RVEF; R2 = 0.64, P = 0.03) and PASP (R2 = 0.71, P = 0.02). Phase of peak RV contractility also correlated inversely to RVEF (R2 = 0.499, P = 0.12) and PASP (R2 = 0.66, P = 0.04). CONCLUSIONS RV contractility analyzed from CMR offers promising non-invasive metrics for classification of PAH, which are congruent with invasive pressure measurements. PMID:25624777

Exercise-induced ST-segment depression and myocardial ischemia in patients with hypertrophic cardiomyopathy. Myocardial scintigraphic study

International Nuclear Information System (INIS)

Miyai, Nobuyuki; Kawasaki, Tatsuya; Taniguchi, Takuya; Kamitani, Tadaaki; Kawasaki, Shingo; Sugihara, Hiroki

2005-01-01

Patients with hypertrophic cardiomyopathy (HCM) sometimes develop myocardial ischemia during exercise in the absence of coronary lesions. The relationship between myocardial ischemia and ST-segment depression was investigated during exercise testing in patients with HCM. Regional hypoperfusion and/or transient left ventricular cavity dilation, a parameter of subendocardial hypoperfusion, were assessed on exercise 99 m Tc-tetrofosmin myocardial scintigraphy in 42 patients with non-obstructive HCM. The scintigraphic results were further correlated with the ST-segment responses to exercise. Regional hypoperfusion or transient left ventricular cavity dilation were observed in 19 (45%) or 16 (38%) patients with HCM, respectively. The incidence of ST-segment depression ≥0.1 mV during exercise testing was similar in HCM patients with regional hypoperfusion, with transient left ventricular cavity dilation, and without hypoperfusion (42%, 38%, 38%, p=0.95). Furthermore, exercise-induced ST-segment depression ≥0.1 mV occurred similarly irrespective of symptoms, exercise tolerance, the degree or the site of hypertrophy, or the presence or absence of resting ST-segment depression. ST-segment depression during exercise testing was common in patients with HCM, but seems to be an unreliable marker of myocardial ischemia as assessed by exercise scintigraphy. (author)

Myocardial scintigraphy

International Nuclear Information System (INIS)

Bunko, Hisashi; Hisada, Kinichi

1982-01-01

Among the various methods of image diagnosis of the cardiovascular disorder, nuclear cardiology provides noninvasive means for evaluation of myocardial perfusion as well as morphological and functional informations. In this article, clinical application and image diagnosis of myocardial scintigraphy including Tl-201 myocardial perfusion scintigraphy, single photon emission computed tomography with Tl-201, acute myocardial infarction scintigraphy with Tc-99m-pyrophosphate and Ga-67 imaging of the heart, were discussed. Multiplanar imaging of the heart with Tl-201 after stress and at redistribution was the accepted method for detection and evaluation of the ischemic heart disease. Although it achieved high sensitivity and specificity for ischemic heart disease, detection of the small ischemia and quantation of the regional Tl-201 accumulation were difficult with conventional multiplanar imaging. Application of emission computed tomography improved detectability and quantitativity of the ischemia. However, 7-pinhole tomography did not increase the diagnostic accuracy significantly. It had limited clinical applicability due to poor quantitativity in spite of improved image contrast and its tomographic nature. Advantage and limitation of these tomographic imaging and multiplanar imaging were discussed. Problems and prognostic significance of pyrophosphate imaging of the acute myocardial infarction were also discussed. Visualization of the heart with Ga-67 was helpful for identification of the tumor or inflammation of the heart as well as evaluation of the effect of the therapy. (author)

Trends in Regionalization of Care for ST-Segment Elevation Myocardial Infarction

Directory of Open Access Journals (Sweden)

Renee Y. Hsia

2017-09-01

Full Text Available Introduction: California has led successful regionalized efforts for several time-critical medical conditions, including ST-segment elevation myocardial infarction (STEMI, but no specific mandated protocols exist to define regionalization of care. We aimed to study the trends in regionalization of care for STEMI patients in the state of California and to examine the differences in patient demographic, hospital, and county trends. Methods: Using survey responses collected from all California emergency medical services (EMS agencies, we developed four categories – no, partial, substantial, and complete regionalization – to capture prehospital and inter-hospital components of regionalization in each EMS agency’s jurisdiction between 2005–2014. We linked the survey responses to 2006 California non-public hospital discharge data to study the patient distribution at baseline. Results: STEMI regionalization-of-care networks steadily developed across California. Only 14% of counties were regionalized in 2006, accounting for 42% of California’s STEMI patient population, but over half of these counties, representing 86% of California’s STEMI patient population, reached complete regionalization in 2014. We did not find any dramatic differences in underlying patient characteristics based on regionalization status; however, differences in hospital characteristics were relatively substantial. Conclusion: Potential barriers to achieving regionalization included competition, hospital ownership, population density, and financial challenges. Minimal differences in patient characteristics can establish that patient differences unlikely played any role in influencing earlier or later regionalization and can provide a framework for future analyses evaluating the impact of regionalization on patient outcomes.

Regional myocardial blood flow, metabolism and function assessed noninvasively by positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Schelbert, H.R.; Phelps, M.E.; Hoffman, E.; Huang, S.; Kuhl, D.E.

1979-01-01

Positron emission computed tomography is a new technique for the noninvasive measure of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study means is due to the technological innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that reflect quantitatively regional tracer tissue concentrations. By employing tracer kinetic models this new technique permits the measurement of regional glucose and fatty acid metabolism of the heart. While already an important new tool for investigative studies into cardiac physiology and pathophysiology, the clinical utility of positron emission tomography remains to be defined.

Regional myocardial blood flow, metabolism and function assessed noninvasively by positron emission tomography

International Nuclear Information System (INIS)

Schelbert, H.R.; Phelps, M.E.; Hoffman, E.; Huang, S.; Kuhl, D.E.

1979-01-01

Positron emission computed tomography is a new technique for the noninvasive measure of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study means is due to the technological innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that reflect quantitatively regional tracer tissue concentrations. By employing tracer kinetic models this new technique permits the measurement of regional glucose and fatty acid metabolism of the heart. While already an important new tool for investigative studies into cardiac physiology and pathophysiology, the clinical utility of positron emission tomography remains to be defined

Sex-dependent effects of sleep deprivation on myocardial sensitivity to ischemic injury.

Science.gov (United States)

Zoladz, Phillip R; Krivenko, Anna; Eisenmann, Eric D; Bui, Albert D; Seeley, Sarah L; Fry, Megan E; Johnson, Brandon L; Rorabaugh, Boyd R

2016-01-01

Sleep deprivation is associated with increased risk of myocardial infarction. However, it is unknown whether the effects of sleep deprivation are limited to increasing the likelihood of experiencing a myocardial infarction or if sleep deprivation also increases the extent of myocardial injury. In this study, rats were deprived of paradoxical sleep for 96 h using the platform-over-water method. Control rats were subjected to the same condition except the control platform was large enough for the rats to sleep. Hearts from sleep deprived and control rats were subjected to 20 min ischemia on a Langendorff isolated heart system. Infarct size and post ischemic recovery of contractile function were unaffected by sleep deprivation in male hearts. In contrast, hearts from sleep-deprived females exhibited significantly larger infarcts than hearts from control females. Post ischemic recovery of rate pressure product and + dP/dT were significantly attenuated by sleep deprivation in female hearts, and post ischemic recovery of end diastolic pressure was significantly elevated in hearts from sleep deprived females compared to control females, indicating that post ischemic recovery of both systolic and diastolic function were worsened by sleep deprivation. These data provide evidence that sleep deprivation increases the extent of ischemia-induced injury in a sex-dependent manner.

Left ventricular contractile function after distal protection in primary percutaneous coronary intervention Results from the Drug Elution and Distal Protection in ST-Elevation Myocardial Infarction trial

DEFF Research Database (Denmark)

Kofoed, K F; Kelbæk, H; Thuesen, L

2011-01-01

Coronary intervention (PCI) may result in an increased infarct size. We evaluated the effect of distal protection during PCI for ST-segment elevation myocardial infarction (STEMI) on myocardial function.......Coronary intervention (PCI) may result in an increased infarct size. We evaluated the effect of distal protection during PCI for ST-segment elevation myocardial infarction (STEMI) on myocardial function....

The effect of heart rate and contractility on the measurement of left ventricular mass by 201Tl SPECT

International Nuclear Information System (INIS)

Machac, J.; Vaquer, R.; Levin, H.; Horowitz, S.F.; Mount Sinai Medical Center, New York

1987-01-01

Left ventricular myocardial mass can be measured by 201 Tl SPECT, but the effects of changes in heart rate and contractility have not been determined. We constructed a dynamic computer model simulating the contracting left ventricle. Thirty two summed static views at each of 3 heart rates and 3 ejection fractions were manufactured to simulate a 180 0 acquisition. Each image set underwent tomographic reconstruction. Left ventricular mass was measured at a fixed percent threshold in each slice. The results show that left ventricular mass varied little with heart rate (4%) and only slightly more (8%) with ejection fraction. Thus, in the normal clinical setting, left ventricular mass measurements by SPECT are minimally affected by the dynamic state of the heart. (orig.)

ST segment elevation after myocardial infarction: Viability or ventricular dysfunction? Comparison with myocardial scintigraphy

International Nuclear Information System (INIS)

Chalela, William Azem; Soares, J. Jr.; Meneghetti, J.C.; Olivera, C.G.; Moffa, P.J.; Falcao, A.M.; Ramires, J.A.F.

2004-01-01

The detection of viable myocardium after myocardial infarction is an important indication for revascularization. We compared exercise-induced ST segment elevation with reversibility at Thallium-201 SPECT scintigraphy and regional wall motion assessment by ventriculography. Thirty two patients with previous myocardial infarction and with left ventricular ejection fraction of < 50% were studied. Patients underwent coronary angiography and Thallium-201 SPECT scintigraphy with re-injection protocol before and after coronary artery bypass graft surgery. Group I comprised 11 patients with ST segment elevation during treadmill stress testing. Group II comprised 21 patients without ST segment elevation. Minimal or moderate hypokinesis was present in 2 patients of Group I and in 4 patients of Group II. Nine patients of Group I and 17 patients of Group II had severe hypokinetic, akinetic or dyskinetic myocardium. Scintigraphy revealed reversibility in the myocardial infarction area in 4 patients from Group I (36.4%) and 11 (52.4%) patients from Group II. Improvement in perfusion after coronary artery bypass grafting was observed in 4 patients from Group I and 8 patients from Group II. Sensitivity, specificity, accuracy, and positive and negative predictive values of ST segment elevation were 33.3, 70.6, 55.2, 44.5 and 60% respectively. It was concluded that exercise-induced ST segment elevation after myocardial infarction is present more frequently in cases of severe regional myocardial dysfunction. (author)

Glucagon-like peptide-1 reduces contractile function and fails to boost glucose utilization in normal hearts in the presence of fatty acids.

Science.gov (United States)

Nguyen, T Dung; Shingu, Yasushige; Amorim, Paulo A; Schwarzer, Michael; Doenst, Torsten

2013-10-09

GLP-1 and exendin-4, which are used as insulin sensitizers or weight reducing drugs, were shown to improve glucose uptake in the heart. However, the direct effects of GLP-1 or exendin-4 on normal hearts in the presence of fatty acids, the main cardiac substrates, have never been investigated. We therefore assessed the effects of GLP-1 or exendin-4 on myocardial glucose uptake (GU), glucose oxidation (GO) and cardiac performance (CP) under conditions of fatty acid utilization. Rat hearts were perfused with only glucose (5 mM) or glucose (5 mM) plus oleate (0.4 mM) as substrates for 60 min. After 30 min, GLP-1 or exendin-4 (0.5 nM or 5 nM) was added. In the absence of oleate, GLP-1 increased both GU and GO. Exendin-4 increased GO but showed no effect on GU. Neither GLP-1 nor exendin-4 affected CP. However, when oleate was present, GLP-1 failed to stimulate glucose utilization and exendin-4 even decreased GU. Furthermore, now GLP-1 reduced CP. In contrast to prior reports, this negative inotropic effect could not be blocked by the protein kinase A inhibitor H-89. We then measured myocardial GO and CP in rats receiving a 4-week GLP-1 infusion. Interestingly, this chronic treatment resulted in a significant reduction in both GO and CP. Under the influence of oleate, GLP-1 reduces contractile function and fails to stimulate glucose utilization in normal hearts. Exendin-4 may acutely reduce cardiac glucose uptake but not contractility. We suggest advanced investigation of heart function and metabolism in patients treating with these peptides. © 2013.

Myocardial scintigraphy with /sup 201/Tl and quantitative assessment of myocardial blood flow

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Ishii, Y; Kanbara, H; Yonekura, Y; Kadota, K; Fujita, T [Kyoto Univ. (Japan). Faculty of Medicine

1976-12-01

A newly introduced radionuclide for myocardial imaging, /sup 201/Tl, was studied. Twenty-two subjects consisting of 7 normals, 12 with ischemic heart disease and 3 with hypertrophic cardiomyopathy (HCM) were selected. On intravenous administration of /sup 201/Tl(1.5 to 20. mCi), initial transit of the tracer through the heart, as well as subsequent uptake by the myocardium, were recorded by a scintillation camera. The later process showed the distribution of the myocardial blood flow (MBF). A normal myocardial scintigraphy revealed the left-sided myocardial mass predominantly, whereas the right side or the septum predominated in the case of tetralogy of fallot (T/F) or idiopathic hypertrophic subuaortic stenosis (IHSS). An ischemic or infarcted area of the myocardium in ischemic heart disease (IHD) was compatible with electrocardiographic findings, and revealed defects even in an equivocal case on ECG. Since the ratio of radioactivity taken up by the myocardium (U) to the total injected dosis (I) is assumed to be proportional to the fractional MBF of cardiac output (CO), MBF/CO is calculated by ratio of the radioactivity selected from myocardial region on the later recording to that from the entire region on the initial transit of the tracer bolus. The average MBF/CO of normals was 4.4 +- 0.5%, IHD 4.0 +- 0.8% and HCM 5.5 +- 1.2%. On exercise loading, a significant increase of this value was observed in normals, whereas no change was observed in IHD.

α,β-Unsaturated aldehyde pollutant acrolein suppresses cardiomyocyte contractile function: Role of TRPV1 and oxidative stress.

Science.gov (United States)

Wu, Zhenbiao; He, Emily Y; Scott, Glenda I; Ren, Jun

2015-01-01

Air pollution is associated with an increased prevalence of heart disease and is known to trigger a proinflammatory response via stimulation of transient receptor potential vanilloid cation channels (TRPV1, also known as the capsaicin receptor). This study was designed to examine the effect of acrolein, an essential α,β-unsaturated aldehyde pollutant, on myocardial contractile function and the underlying mechanism involved with a focus on TRPV1 and oxidative stress. Cardiomyocyte mechanical and intracellular Ca(2+) properties were evaluated using an IonOptix MyoCam® system including peak shortening (PS), maximal velocity of shortening/relengthening (± dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR90 ), fura-2 fluorescence intensity (FFI) and intracellular Ca(2+) decay. Changes in apoptosis and TRPV1 were evaluated using Western blot analysis. The degree of oxidative stress was assessed using the ratio between reduced and oxidized glutathione. Results obtained revealed that exposure of cardiomyocytes to acrolein acutely compromised contractile and intracellular Ca(2+) properties including depressed PS, ± dL/dt and ΔFFI, as well as prolonged TR90 and intracellular Ca(2+) decay. In addition, acrolein exposure upregulated TRPV1 associated with an increase in both apoptosis and oxidative stress. However, the acrolein-induced cardiomyocyte contractile and intracellular Ca(2+) anomalies, as well as apoptosis (as evidenced by Bcl-2, Bax, FasL, Caspase-3 and -8), were negated by the reactive oxygen species (ROS) scavenger glutathione or the TRPV1 antagonist capsazepine. Collectively these data suggest that the α,β-unsaturated aldehyde pollutant acrolein may play a role in the pathogenesis and sequelae of air pollution-induced heart disease via a TRPV1- and oxidative stress-dependent mechanism. © 2013 Wiley Periodicals, Inc.

Reverse redistribution phenomenon on rest 99mTc-tetrofosmin myocardial single photon emission computed tomography involves impaired left ventricular contraction in patients with acute myocardial infarction

International Nuclear Information System (INIS)

Kurokawa, Kazuyuki; Ohte, Nobuyuki; Miyabe, Hiromichi; Akita, Sachie; Yajima, Kazuhiro; Hayano, Junichiro; Kimura, Genjiro

2003-01-01

The purpose of this study was to investigate the clinical significance of the reverse redistribution (RR) phenomenon on technetium-99m ( 99m Tc)-tetrofosmin myocardial single photon emission computed tomography (SPECT) performed at rest. Twenty-five patients underwent myocardial SPECT 3 weeks after the onset of acute myocardial infarction. Myocardial images were acquired at 40 min (early) and 4 h (delayed) after the injection of 740 MBq of 99m Tc-tetrofosmin. The regional myocardial uptake of the tracer in 26 segments of the left ventricular (LV) wall was visually scored from 0 (no activity) to 3 (normal activity), and then the RR was defined as a decrease of more than 1 point in the activity score on the delayed image compared with that on the early image. Regions with an activity score of 3 on both the early and delayed images were defined as normal, and those with a score of 0 or 1 on the early image were considered to have a fixed defect. The regional myocardial 99m Tc-tetrofosmin uptake and washout rate were also quantitatively assessed in each region. In addition, exercise stress electrocardiograph-gated SPECT with 99m Tc-tetrofosmin was performed within 1 week of the rest study, and the percent count increase (%CI) during myocardial contraction in each corresponding region was studied. RR was observed in 18 of the 25 patients. The regional washout rate of 99m Tc-tetrofosmin was significantly higher in the RR regions (45.0±3.8%) than in either the normal regions (36.4±4.1%, p 99m Tc-tetrofosmin SPECT have severely impaired LV wall contraction after exercise. (author)

[Contractile function of the heart and myocardium antioxidant system in rats of August and Wistar strains during ischemia and reperfusion].

Science.gov (United States)

Sazontova, T G; Belkina, L M; Zhukova, A G; Kirillina, T N; Arkhipenko, Iu V

2004-01-01

In August rats, local myocardial ischemia caused by 30-min occlusion of the coronary artery induced a slight depression of the contractile function of the heart; the latter was restored after 15-min reperfusion more rapidly than in Wistar rats. In August rats, the activities of antioxidant protection enzymes were lower than in Wistar rats. In comparison with Wistar rats, these enzyme activities were decreased in a lesser degree under ischemia and were restored in a greater degree under reperfusion. It may thus be concluded that the higher stability of antiradical protection parameters in August rats is one of the mechanisms responsible for the enhanced resistance of the heart to ischemia- and reperfusion-induced injuries.

Influence of revascularization on myocardial perfusion, metabolism and function evaluated with I-123-IPPA

International Nuclear Information System (INIS)

Kropp, J.; Krois, M.; Eichhorn, B.; Feske, W.; Likungu, J.; Kirchhoff, P.J.; Luederitz, B.; Biersack, H.J.; Knapp, F.F. Jr.

1993-01-01

Patients with coronary artery disease (CAD) were investigated with sequential SPECT-scintigraphy after administration of 200 MBq of 15-(p-[I-123]iodophenyl)pentadecanoic acid (IPPA) at peak submaximal exercise. Twenty patients underwent coronary angioplasty (PTCA) from which 14 had control coronary arteriography (CA) and left ventricular cineventriculography (LVCV). Nineteen pts underwent bypass graft surgery (ACB) and stress sonagraphy. Semi-quantification of uptake (Up related to perfusion) and turnover (Tr) was obtained by segmental comparison of oblique slices. About 90% of the reperfused myocardial segments in the PTCA-group and 76% in the ACB-group showed an improvement of uptake after therapy (RUp). Of these, 50% and 66% exhibited increased turnover (RTr) after PTCA or ACB. Pathologic RTr was highly correlated with regional wall motion abnormalities after therapy in both groups. In the ACB-group presence of improvement of RTr was correlated with improved RWM at rest and stress. IPPA-studies show potential to provide information about changes of perfusion and metabolism after reperfusion and IPPA-turnover is a good predictor of the pattern of contractile function

Regional myocardial extraction of a radioiodinated branched chain fatty acid during right ventricular pressure overload due to acute pulmonary hypertension

International Nuclear Information System (INIS)

Hurford, W.; Lowenstein, E.; Zapol, W.; Barlai-Kovach, M.; Livni, E.; Elmaleh, D.R.; Strauss, H.W.

1985-01-01

To determine whether branched chain fatty acid extraction is reduced during right ventricular (RV) dysfunction due to acute pulmonary artery hypertension, studies were done in 6 anesthetized dogs. Regional branched chain fatty acid extraction was measured by comparing the myocardial uptake of I-125 labeled 15-[p-(iodophenyl)]-3-methylpentadecanoic acid (I-PDA) to myocardial blood flow. Acute pulmonary hypertension was induced by incremental intravenous injection of 100 micron diameter glass beads into six pentobarbital anesthetized, mechanically ventilated dogs. Myocardial blood flow was measured by radiolabeled microspheres both under baseline conditions and during pulmonary hypertension. Mean RV pressure rose from 12 +- 2 (mean +- SEM) to 30 +-3mmHg resulting in a 225 +- 16% increase in RV stroke work. RV ejection fraction, as assessed by gated blood pool scans fell from 39 +- 2 to 18 +- 2%. Left ventricular (LV) pressures, stroke work and ejection fraction were unchanged. Myocardial blood flow increased 132 + 59% in the RV free wall and 67 +- 22% in the RV septum. LV blood flow was unchanged. Despite increased RV work and myocardial blood flow, no differences were noted in the branched chain fatty acid extraction ratios among LV or RV free walls or septum. The authors conclude that early RV dysfunction associated with pulmonary artery hypertension is not due to inadequate myocardial blood flow or branched chain fatty acid extraction

Diagnostics of the myocardium with radionuclides

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Adam, W E; Geffers, H; Sigel, H; Kampmann, H; Stauch, M [Ulm Univ. (Germany, F.R.). Sektion Nuklearmedizin

1976-11-01

Three aspects allow description of myocardial functional state: perfusion, motility and disturbance of structure, to all of which nuclear medicine can provide information. Distribution of /sup 201/thallium reflects myocardial perfusion distribution. Diminished accumulation of radioactive kalium, rubidium, caesium on thallium is correlated to reduced or abolished perfusion in areas of destroyed myocardial structure (infarction), the latter is marked by increased sup(99m)Tc-pyrophosphate-uptake caused by increased permeability of cellular membranes. Motility can be described globally or regionally by analysis or regional wall motion. Among global parameters ejection fraction as a measure for diminished myocardial contractility was of great interest. However, parameters for evaluation of regional myocardial motility are in the centre of interest. Camera-cinematography is the approach to analyse precordial countrate changes as time volume equivalents caused by cyclic cardial volume changes. The results allow to deliniate areas of hypokinesis and akinesis, areas of dyskinesis with phase shifting in comparison to normokinetic areas, at least evaluation of dV/dtsub(max) for contractility and relaxation. The results of normal subjects without heart disease show excellent reproducibility with strong correlation. The results of 165 patients suspected to have coronary heart disease or vitium cordis delivered additional information in part, in 27 of 29 cases results were identical to conventional invasive cineangiography. Comparison of ejection fraction measured scintigraphically and ventriculographically with the area-diameter-method revealed excellent correlation (r = 0,93).

Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling.

Directory of Open Access Journals (Sweden)

Jiaojiao Pang

Full Text Available The endoplasmic reticulum (ER plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs. Myocardial mechanical and intracellular Ca(2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca(2+ homeostasis, oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62, along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

Role of myocardial perfusion imaging in evaluating thrombolytic therapy for acute myocardial infarction

International Nuclear Information System (INIS)

Beller, G.A.

1987-01-01

Myocardial thallium-201 scintigraphy is being increasingly employed as a method for assessing the efficacy of coronary reperfusion in acute myocardial infarction. New thallium uptake after intracoronary tracer administration after successful recanalization indicates that nutrient blood flow has been successfully restored. One may also presume that some myocardial salvage occurred if thallium administered in this manner is transported intracellularly by myocytes with intact sarcolemmal membranes. However, if one injects thallium by way of the intracoronary route immediately after reperfusion, the initial uptake of thallium in reperfused myocardium may predominantly represent hyperemic flow and regional thallium counts measured may not be proportional to the mass of viable myocytes. When thallium is injected intravenously during the occlusion phase the degree of redistribution after thrombolysis is proportional to the degree of flow restoration and myocardial viability. When thallium is injected for the first time intravenously immediately after reperfusion, an overestimation of myocardial salvage may occur because of excess thallium uptake in the infarct zone consequent to significant hyperemia. Another approach to myocardial thallium scintigraphy in patients undergoing thrombolytic therapy is to administer two separate intravenous injections before and 24 hours or later after treatment. Finally, patients with acute myocardial infarction who receive intravenous thrombolytic therapy are candidates for predischarge exercise thallium-201 scintigraphy for risk stratification and detection of residual ischemia

T1 mapping of the myocardium: Intra-individual assessment of the effect of field strength, cardiac cycle and variation by myocardial region

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Kawel Nadine

2012-05-01

Full Text Available Abstract Background Myocardial T1 relaxation time (T1 time and extracellular volume fraction (ECV are altered in the presence of myocardial fibrosis. The purpose of this study was to evaluate acquisition factors that may result in variation of measured T1 time and ECV including magnetic field strength, cardiac phase and myocardial region. Methods 31 study subjects were enrolled and underwent one cardiovascular MR exam at 1.5 T and two exams at 3 T, each on separate days. A Modified Look-Locker Inversion Recovery (MOLLI sequence was acquired before and 5, 10, 12, 20, 25 and 30 min after administration of 0.15 mmol/kg gadopentetate dimeglumine (Gd-DTPA; Magnevist at 1.5 T (exam 1. For exam 2, MOLLI sequences were acquired at 3 T both during diastole and systole, before and after administration of Gd-DTPA (0.15 mmol/kg Magnevist.Exam 3 was identical to exam 2 except gadobenate dimeglumine was administered (Gd-BOPTA; 0.1 mmol/kg Multihance. T1 times were measured in myocardium and blood. ECV was calculated by (ΔR1myocardium/ΔR1blood*(1-hematocrit. Results Before gadolinium, T1 times of myocardium and blood were significantly greater at 3 T versus 1.5 T (28% and 31% greater, respectively, p  Conclusion ECV is similar at field strengths of 1.5 T and 3 T. Due to minor variations in T1 time and ECV during the cardiac cycle and in different myocardial regions, T1 measurements should be obtained at the same cardiac phase and myocardial region in order to obtain consistent results.

VIABILIDAD MIOCÁRDICA Y LOS PRINCIPALES MÉTODOS PARA SU DETECCIÓN / Myocardial viability and the main methods for its evaluation

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Iguer F Aladro Miranda

2009-09-01

Full Text Available The reduction of mortality due to ischemic heart disease is one of the objectives of the Health Systems in the developed nations, and in Cuba as well. After an acute myocardial infarction, or after a chronic obstruction of a coronary artery, a contractile dysfunction of the cardiac muscle appears. This dysfunction can be partially or totally reversible. With a surgical and percutaneous myocardialrevascularization it is possible to restore the flow of blood to the ischemic area; however, these procedures would be in vain if the reperfused muscle is not viable. That is why the tests which assess the myocardial viability are so important and represent an indispensable tool to guarantee the success. During the last years some concepts have been modified, some diagnosis techniques have been developed; and the therapeutics, both medical and surgical, is in a process of evolution. The most useful diagnosis methods to determine myocardial viability are commented in this article.

Mismatched regional myocardial uptake between [sup 123]I-BMIPP and [sup 201]Tl SPECT; Comparison between hypertrophic myocardium and dilated myocardium

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Otsuka, Makoto; Ichiya, Yuichi; Kuwabara, Yasuo; Sasaki, Masayuki; Fukumura, Toshimitsu; Masuda, Kouji; Ejima, Junichi; Tsuda, Yasuo (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

1992-07-01

The distribution of a new myocardial fatty acid metabolic agent [sup 123]I-BMIPP was compared in 6 each patients with hypertrophic myocardium (4 cases of hypertensive heart disease and 2 of hypertrophic cardiomyopathy) and dilated myocardium (4 of dilated type of valvular heart disease and 2 of dilated cardiomyopathy) with that of [sup 201]Tl. Mismatched regional myocardial uptake between [sup 123]I-BMIPP and [sup 201]Tl SPECT was observed in all of the hypertrophic myocardium, however no but one in the dilated myocardium. Relative increase or decrease in regional BMIPP from the images of 20 min and to those of 4 h was observed in 3 cases of the hypertrophic myocardium. FDG-PET was performed in 2 cases of the hypertrophic myocardium. The distribution of FDG was different from neither those of BMIPP nor Tl in a hypertrophic cardiomyopathy case with the reserved distribution of BMIPP and Tl. Although more investigations are necessary, we concluded that [sup 123]I-BMIPP is a promising radiopharmaceutical for evaluating myocardial fatty acid metabolism in hypertrophic myocardium. (author).

Bone marrow mononuclear cell implantation in myocardial laser channels in the ischemic heart disease surgery. Long-term results

Science.gov (United States)

Chernyavskiy, Alexander; Fomichev, Alexey; Minin, Stanislav; Nikitin, Nikita

2017-10-01

Background: The problem of incomplete myocardial revascularization for diffuse and distal lesions of the myocardium is still relevant. We assessed the clinical and instrumental long-term results of autologous bone marrow cell (BMC) implantation in laser channels in ischemic heart disease with diffuse and distal coronary disease. 35 coronary heart disease (CHD) patients with diffuse and distal coronary disease during coronary artery bypass grafting (CABG) underwent BMC implantation in laser channels. The control group consisted of 29 patients. All patients in this group underwent only CABG. Clinical and instrumental assessment of the method's effect was carried out at two weeks, six months, and six years after surgery. Indirect revascularization showed more significant decreasing of the functional class (FC) New York Heart Association (NYHA), myocardial perfusion and contractility improvement. Autologous BMC implantation in laser channels is an effective method of CHD surgical treatment if it is impossible to perform direct myocardial revascularization. The indirect revascularization effect is formed in the first six months after surgery and remains at the same level for six years.

Regional myocardial blood flow distribution during intracoronary infusion of parathyroid hormone

International Nuclear Information System (INIS)

Crass, M.F. III; Lust, R.M.

1986-01-01

Although low doses of the biologically-active fragment of parathyroid hormone PTH-(1-34), have been shown to produce potent dilation of the coronary circulation specific regional and transmural (endo/epi) myocardial blood flow (MBF) responses to the hormone have not been described. Anesthetized open-chest mongrel dogs were instrumented to quantitate coronary blood flow and other cardiodynamic parameters. PTH-(1-34) was infused into the left circumflex artery (.008 nmol kg -1 min -1 ). Using the reference withdrawal method, radionuclide-labeled microspheres were injected before (basal flow), during (8 min after new steady-state flow), and after (restoration of basal flow) a 20 min infusion of PTH-(1-34). MFB increased from 76 +- 1.9 to 152 +- 3.5 ml min -1 100 g -1 (P < .001) during PTH-(1-34) infusion. No differences in endo/epi flow ratio or regional coronary blood flow within the left ventricle were detected. Thus, in anesthetized dogs, the increase in MBF observed secondary to the PTH-(1-34)-induced decrease in coronary resistance appeared to be uniform transmurally and regionally, and is probably not the result of a shunting or steal phenomenon

Quantifying esophagogastric junction contractility with a novel HRM topographic metric, the EGJ-Contractile Integral: normative values and preliminary evaluation in PPI non-responders.

Science.gov (United States)

Nicodème, F; Pipa-Muniz, M; Khanna, K; Kahrilas, P J; Pandolfino, J E

2014-03-01

Despite its obvious pathophysiological relevance, the clinical utility of measures of esophagogastric junction (EGJ) contractility is unsubstantiated. High-resolution manometry (HRM) may improve upon this with its inherent ability to integrate the magnitude of contractility over time and length of the EGJ. This study aimed to develop a novel HRM metric summarizing EGJ contractility and test its ability distinguish among subgroups of proton pump inhibitor non-responders (PPI-NRs). 75 normal controls and 88 PPI-NRs were studied. All underwent HRM. PPI-NRs underwent pH-impedance monitoring on PPI therapy scored in terms of acid exposure, number of reflux events, and reflux-symptom correlation and grouped as meeting all criteria, some criteria, or no criteria of abnormality. Control HRM studies were used to establish normal values for candidate EGJ contractility metrics, which were then compared in their ability to differentiate among PPI-NR subgroups. The EGJ contractile integral (EGJ-CI), a metric integrating contractility across the EGJ for three respiratory cycles, best distinguished the All Criteria PPI-NR subgroup from controls and other PPI-NR subgroups. Normal values (median, [IQR]) for this measure were 39 mmHg-cm [25-55 mmHg-cm]. The correlation between the EGJ-CI and a previously proposed metric, the lower esophageal sphincter-pressure integral, that used a fixed 10 s time frame and an atmospheric as opposed to gastric pressure reference was weak. Among HRM metrics tested, the EGJ-CI was best in distinguishing PPI-NRs meeting all criteria of abnormality on pH-impedance testing. Future prospective studies are required to explore its utility in management of broader groups of gastroesophageal reflux disease patients. © 2013 John Wiley & Sons Ltd.

Cintilografia de perfusão miocárdica sob baixa dose de dobutamina na identificação do miocárdio viável Low-dose dobutamine myocardial perfusion scintigraphy in the identification of viable myocardium

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Renata Freire de Moraes

2010-10-01

Full Text Available OBJETIVO: Verificar se a cintilografia de perfusão miocárdica duoisotópica(99mTc-sestamibi/tálio-201, método de alta sensibilidade para identificação do músculo viável, tem sua especificidade aumentada com a inclusão de informações sobre reserva contrátil miocárdica obtidas simultaneamente através de gated SPECT na vigência de baixas doses de dobutamina de forma semelhante ao ecocardiograma. MATERIAIS E MÉTODOS: Estudaram-se 260 segmentos miocárdicos de 13 pacientes com infarto do miocárdio, encaminhados para pesquisa de viabilidade antes do procedimento de revascularização. Avaliaram-se a integridade celular e a reserva contrátil pela cintilografia de perfusão miocárdica duoisotópica com imagens de repouso e redistribuição do tálio-201 e de estresse (99mTc-sestamibi gated SPECT, em condições basais e na vigência de baixas doses de dobutamina. A melhora do desempenho contrátil em controle cintilográfico pós-revascularização (99mTc-sestamibi gated SPECT confirmava a presença de viabilidade. Para análise dos resultados quantificaram-se os parâmetros funcionais dos segmentos miocárdicos nas diferentes etapas do estudo, estratificando-os quanto à viabilidade para posterior comparação funcional pós-revascularização. RESULTADOS: No tratamento estatístico a análise do espessamento sistólico se destacou como parâmetro de avaliação da reserva contrátil miocárdica pelo método, mostrando tendência a incremento na especificidade (84%, demonstrando valores superiores aos da literatura. CONCLUSÃO: O método tende a apresentar contribuições efetivas na busca do miocárdio viável.OBJECTIVE: To evaluate the increase in specificity of dual isotope myocardial perfusion gated SPECT (99mTc-sestamibi/thallium-201, a highly sensitive method to detect viable myocardium, with addition of data on contractile reserve simultaneously acquired by low-dose dobutamine gated SPECT, similarly to echocardiography

Regional myocardial oxygen consumption determined noninvasively in humans with [1-11C]acetate and dynamic positron tomography

International Nuclear Information System (INIS)

Armbrecht, J.J.; Buxton, D.B.; Brunken, R.C.; Phelps, M.E.; Schelbert, H.R.

1989-01-01

Experimental studies of animals have previously demonstrated the validity of [1-11C]acetate as a tracer of oxidative metabolism for use with positron emission tomography. The present study was undertaken to define in normal human volunteers the relation between myocardial clearance kinetics of [1-11C]acetate, and the rate-pressure product as an index of myocardial oxygen consumption. Twenty-two studies were performed of 12 volunteers. The rate-pressure product was increased with continuous supine bicycle exercise in six studies. Of the 16 resting studies, seven were performed in the fasted state and nine following an oral glucose load, to define possible effects of substrate availability on the tracer-tissue kinetics. Myocardial tissue time-activity curves were biexponential. Clearance of activity was homogeneous throughout the myocardium. The rate constants k1, obtained from biexponential fitting, and kmono, obtained by monoexponential fitting of the initial linear portion of the time-activity curves, correlated well with the rate-pressure product. Although the correlation coefficient was higher for k1 than for kmono (0.95 vs. 0.91), analysis on a sectorial basis showed less regional variability in kmono. This suggests that kmono, which is more practical than k1 because it requires shorter acquisition times, may be more clinically and experimentally useful for detection of myocardial segments with abnormal oxygen consumption. Overall, changes in myocardial substrate supply were without significant effect on the relation between the rate constants (k1 and kmono) and the rate-pressure product, although a small decrease in kmono/rate-pressure product was observed following oral glucose by paired analysis in four subjects

Myocardial uptake of cocaine and effects of cocaine on myocardial substrate utilization and perfusion in hypertensive rats

Energy Technology Data Exchange (ETDEWEB)

Som, P.; Wang, G.J. [Brookhaven National Lab., Upton, NY (United States); Oster, Z.H. [State Univ. of New York, Stony Brook, NY (United States); Knapp, F.F. Jr. [Oak Ridge National Lab., TN (United States); Yonekura, Y. [Kyoto Univ. (Japan). Faculty of Medicine; Fujibayashi, Y. [Kyoto Univ. (Japan). Hospital; Yamamoto, K. [Fukui Univ. (Japan). Medical School; Kubota, K. [Tohoku Univ., Sendai (Japan)

1992-12-31

Cocaine abuse is a problem causing world-wide concern and the number of deaths following cocaine use is increasing. Cardiovascular complications following cocaine include severe tachyarrythmias, pulmonary edema, myocardial infarction, and acute renal failure, which are major problems confronting emergency facilities. While the studies of cocaine effects on the brain have been given the most attention, it is clear that the effects of cocaine on the cardiovascular system are of great importance, given the increasing number of reports on sudden death and myocardial infarctions in young adults related to cocaine use. The precise mechanisms of cardiotoxic actions of cocaine are unclear. We investigated the whole-body distribution of C-14-labeled cocaine to determine the cocaine-binding sites, including blocking experiments to determine the nature of regional binding sites, and differential response of the normal vs. diseased heart (hypertensive cardiomyopathy) in an animal model to mimic a potentially high risk population. We investigated the acute effects of cocaine on myocardial metabolism using two myocardial energy substrate analogs, fatty acid and glucose with comparison with regional perfusion.

Myocardial uptake of cocaine and effects of cocaine on myocardial substrate utilization and perfusion in hypertensive rats

Energy Technology Data Exchange (ETDEWEB)

Som, P.; Wang, G.J. (Brookhaven National Lab., Upton, NY (United States)); Oster, Z.H. (State Univ. of New York, Stony Brook, NY (United States)); Knapp, F.F. Jr. (Oak Ridge National Lab., TN (United States)); Yonekura, Y. (Kyoto Univ. (Japan). Faculty of Medicine); Fujibayashi, Y. (Kyoto Univ. (Japan). Hospital); Yamamoto, K. (Fukui Univ. (Japan). Medical School); Kubota, K. (Tohoku Univ., Sendai

1992-01-01

Cocaine abuse is a problem causing world-wide concern and the number of deaths following cocaine use is increasing. Cardiovascular complications following cocaine include severe tachyarrythmias, pulmonary edema, myocardial infarction, and acute renal failure, which are major problems confronting emergency facilities. While the studies of cocaine effects on the brain have been given the most attention, it is clear that the effects of cocaine on the cardiovascular system are of great importance, given the increasing number of reports on sudden death and myocardial infarctions in young adults related to cocaine use. The precise mechanisms of cardiotoxic actions of cocaine are unclear. We investigated the whole-body distribution of C-14-labeled cocaine to determine the cocaine-binding sites, including blocking experiments to determine the nature of regional binding sites, and differential response of the normal vs. diseased heart (hypertensive cardiomyopathy) in an animal model to mimic a potentially high risk population. We investigated the acute effects of cocaine on myocardial metabolism using two myocardial energy substrate analogs, fatty acid and glucose with comparison with regional perfusion.

Advances in computational modelling for personalised medicine after myocardial infarction.

Science.gov (United States)

Mangion, Kenneth; Gao, Hao; Husmeier, Dirk; Luo, Xiaoyu; Berry, Colin

2018-04-01

Myocardial infarction (MI) is a leading cause of premature morbidity and mortality worldwide. Determining which patients will experience heart failure and sudden cardiac death after an acute MI is notoriously difficult for clinicians. The extent of heart damage after an acute MI is informed by cardiac imaging, typically using echocardiography or sometimes, cardiac magnetic resonance (CMR). These scans provide complex data sets that are only partially exploited by clinicians in daily practice, implying potential for improved risk assessment. Computational modelling of left ventricular (LV) function can bridge the gap towards personalised medicine using cardiac imaging in patients with post-MI. Several novel biomechanical parameters have theoretical prognostic value and may be useful to reflect the biomechanical effects of novel preventive therapy for adverse remodelling post-MI. These parameters include myocardial contractility (regional and global), stiffness and stress. Further, the parameters can be delineated spatially to correspond with infarct pathology and the remote zone. While these parameters hold promise, there are challenges for translating MI modelling into clinical practice, including model uncertainty, validation and verification, as well as time-efficient processing. More research is needed to (1) simplify imaging with CMR in patients with post-MI, while preserving diagnostic accuracy and patient tolerance (2) to assess and validate novel biomechanical parameters against established prognostic biomarkers, such as LV ejection fraction and infarct size. Accessible software packages with minimal user interaction are also needed. Translating benefits to patients will be achieved through a multidisciplinary approach including clinicians, mathematicians, statisticians and industry partners. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless

Myocardial imaging with 99mTc-Tetrofosmin: Influence of post-stress acquisition time, regional radiotracer uptake, and wall motion abnormalities on the clinical result.

Science.gov (United States)

Giorgetti, Assuero; Kusch, Annette; Casagranda, Mirta; Tagliavia, Irene D'Aragona; Marzullo, Paolo

2010-04-01

We previously demonstrated that early (15', T1) post-stress myocardial imaging with Tetrofosmin could be more accurate than standard acquisitions (45', T2) in identifying coronary artery disease. To clarify this phenomenon, 120 subjects (age 61 +/- 10 years) with both T1 and T2 scans were divided into Group 1 (53/120 pts) with more ischemia at T1 vs T2 imaging (T1-T2SDS > or = 3); Group 2 (67/120 pts) with similar results (T1-T2SDS statistic and semiquantitative wall motion/thickening values were obtained. Analysis of T1 and T2 post-stress myocardial counts demonstrated a significant Tetrofosmin wash-out rate that was higher in Group 1 control nonischemic regions (15 +/- 8% vs 13.6 +/- 9.6%, P stress wall thickening (T1-T2) was lower in Group 1 ischemic regions (-4.5 +/- 9.15% vs -1.90 +/- 7.0%, P stress acquisition time because of ischemic-induced regional wall thickening abnormalities and the existence of a differential radiotracer myocardial wash-out.

Association of Exercise Training with Tobacco Smoking Prevents Fibrosis but has Adverse Impact on Myocardial Mechanics.

Science.gov (United States)

Reis Junior, Dermeval; Antonio, Ednei Luiz; de Franco, Marcello Fabiano; de Oliveira, Helenita Antonia; Tucci, Paulo José Ferreira; Serra, Andrey Jorge

2016-12-01

There was no data for cardiac repercussion of exercise training associated with tobacco smoking. This issue is interesting because some smoking people can be enrolled in an exercise-training program. Thus, we evaluated swimming training effects on the function and structural myocardial in rats exposed to tobacco smoking. Male Wistar rats were assigned to one of four groups: C, untrained rats without exposure to tobacco smoking; E, exercised rats without exposure to tobacco smoking; CS, untrained rats exposed to tobacco smoking; ECS, exercised rats exposed to tobacco smoking. Rats swam five times a week twice daily (60min per session) for 8 weeks. Before each bout exercise, rats breathed smoke from 20 cigarettes for 60min. Twenty-four hours after the last day of the protocol, papillary muscles were isolated for in vitro analysis of myocardial mechanics. The myocardial mass and nuclear cardiomyocyte volume were used as hypertrophy markers, and collagen content was determined by picrosirius red staining. There was a well-pronounced myocardial hypertrophic effect for two interventions. The exercise blunted myocardial collagen increases induced by tobacco smoking. However, exercise and tobacco-smoking association was deleterious to myocardial performance. Thereby, in vitro experiments with papillary muscles contracting in isometric showed impairment myocardial inotropism in exercised rats exposed to tobacco smoking. This work presents novel findings on the role of exercise training on cardiac remodeling induced by tobacco smoking. Although exercise has mitigated tissue fibrosis, their association with tobacco smoking exacerbated hypertrophy and in vitro myocardial dysfunction. This is first study to show that the association of an aerobic exercise training with tobacco smoking intensifies the phenotype of pathological cardiac hypertrophy. Therefore, the combination of interventions resulted in exacerbated myocardial hypertrophy and contractility dysfunction. These

Detecting cardiac contractile activity in the early mouse embryo using multiple modalities

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Chiann-mun eChen

2015-01-01

Full Text Available The heart is one of the first organs to develop during mammalian embryogenesis. In the mouse, it starts to form shortly after gastrulation, and is derived primarily from embryonic mesoderm. The embryonic heart is unique in having to perform a mechanical contractile function while undergoing complex morphogenetic remodelling. Approaches to imaging the morphogenesis and contractile activity of the developing heart are important in understanding not only how this remodelling is controlled but also the origin of congenital heart defects. Here, we describe approaches for visualising contractile activity in the developing mouse embryo, using brightfield time lapse microscopy and confocal microscopy of calcium transients. We describe an algorithm for enhancing this image data and quantifying contractile activity from it. Finally we describe how atomic force microscopy can be used to record contractile activity prior to it being microscopically visible.

Detection of viable myocardium in canine model with myocardial ischemia and ischemia-reperfusion by 125I-BMIPP: relation to regional blood flow

International Nuclear Information System (INIS)

Huang Gang; Zhao Huiyang; Shen Xuedong; Li Qing; Yuan Jimin; Zhu Cuiying

1999-01-01

Objective: The effects of BMIPP (β-methyl-iodophenyl pentadecanoic acid) on detecting viable myocardium and the relation between regional blood flow and the uptake of BMIPP were evaluated in canine model of myocardial ischemia and ischemia-reperfusion. Methods: 12 open-chest dogs under anesthesia were divided into two groups. Group I (ischemia group) had left circumflex coronary arterial occlusion for 2 h and group II (ischemia-reperfusion group) was occluded for 1 h and followed by 2 h reperfusion. Myocardial blood flow was measured with 99 Tc m -microspheres. 30 min after intravenous injection of 125 I-BMIPP and 99 Tc m -microspheres, the heart was excised rapidly and stained with Evans blue and NBT. Tissue samples (divided into approximately 1 g) of left ventricle were obtained, weighed and counted for 125 I and 99 Tc m . Regional blood flow and the uptake of BMIPP were expressed as percentages of average values in non-ischemic myocardium (two to three tissue samples) from the normal myocardium. Results: In ischemic myocardium (NBT positive samples), the uptake of BMIPP was relatively higher compared with regional blood flow [(67 +- 23)% vs (42 +- 19)%, P 0.05]. In ischemia-reperfusion group, regional blood flow was increased in ischemic and necrotic tissues, but the uptake of BMIPP was not enhanced with the increasing blood flow. Conclusions: BMIPP uptake seems to provide metabolic information independent of regional blood flow. The mismatching between regional blood flow and BMIPP uptake may indicate myocardial viability in the regions of hypoperfusion and the uptake of BMIPP in ischemic myocardium was related to existence of cellular metabolism

Detecting Regional Myocardial Abnormalities in Patients With Wolff-Parkinson-White Syndrome With the Use of ECG-Gated Cardiac MDCT.

Science.gov (United States)

Lee, Hye-Jeong; Uhm, Jae-Sun; Joung, Boyoung; Hong, Yoo Jin; Hur, Jin; Choi, Byoung Wook; Kim, Young Jin

2016-04-01

Myocardial dyskinesia caused by the accessory pathway and related reversible heart failure have been well documented in echocardiographic studies of pediatric patients with Wolff-Parkinson-White (WPW) syndrome. However, the long-term effects of dyskinesia on the myocardium of adult patients have not been studied in depth. The goal of the present study was to evaluate regional myocardial abnormalities on cardiac CT examinations of adult patients with WPW syndrome. Of 74 patients with WPW syndrome who underwent cardiac CT from January 2006 through December 2013, 58 patients (mean [± SD] age, 52.2 ± 12.7 years), 36 (62.1%) of whom were men, were included in the study after the presence of combined cardiac disease was excluded. Two observers blindly evaluated myocardial thickness and attenuation on cardiac CT scans. On the basis of CT findings, patients were classified as having either normal or abnormal findings. We compared the two groups for other clinical findings, including observations from ECG, echocardiography, and electrophysiologic study. Of the 58 patients studied, 16 patients (27.6%) were found to have myocardial abnormalities (i.e., abnormal wall thinning with or without low attenuation). All abnormal findings corresponded with the location of the accessory pathway. Patients with abnormal findings had statistically significantly decreased left ventricular function, compared with patients with normal findings (p syndrome. These abnormal findings might reflect the long-term effects of dyskinesia, suggesting irreversible myocardial injury that ultimately causes left ventricular dysfunction.

Cardiac inotropic reserve examined by postextrasystolic potentiation and redistribution of exercise thallium-201 scintigraphy

International Nuclear Information System (INIS)

Sugihara, Hiroki; Adachi, Haruhiko; Nakagawa, Hiroaki

1986-01-01

Evaluation of regional contractile reserve and the viability of an infarcted segment of the myocardium is very important in determining the indications for aorto-coronary bypass after myocardial infarction and in predicting the prognosis. Regional wall motion of the left ventricle after postextrasystolic potentiation (PESP) was studied in 18 patients with old myocardial infarction, and compared with indices of redistribution of thallium after exercise. Equilibrium radionuclide angiocardiography (RNA) using Tc 99m HSA was performed at rest and after PESP produced by a programmable cardiac stimulator via a right ventricular catheter. Regional ejection fractions (REF) were determined, and wall motion was observed visually. The relative thallium activity (RTA) and washout rate (WOR) were obtained from exercise myocardial scintigraphy performed 10 minutes, and 3 hours after thallium-201 injections. Wall motion improved in 12 of 23 infarcted segments after PESP. Regional ejection fraction and relative thallium activity (in three hours, or the difference between the activities of the initial and three hours after exercise) in the improved segments were significantly higher (p < 0.001) than in the unchanged segments. Washout rate was lower (p < 0.02) in the improved segments. Significant correlation was observed between the change in regional ejection fraction and relative thallium activity (3 hours after exercise) (r = 0.654, p < 0.05). Thus, the wall motion of some infarcted regions of the myocardium improved after PESP, and thallium was redistributed during three hours after exercise. It is concluded that contractility and viability might be preserved even in the infarcted site following myocardial infarction, and that these results are indications for aorto-coronary bypass surgery in cases of old myocardial infarction. Both PESP assessed by equilibrium radionuclide angiography and exercise thallium scintigraphy are useful means for these evaluations. (author)

Abnormal myocardial free fatty acid utilization deteriorates with morphological changes in the hypertensive heart

International Nuclear Information System (INIS)

Nakayama, Hiroyuki; Morozumi, Takakazu; Nanto, Shinsuke

2001-01-01

The left ventricle's morphological adaptation to high blood pressure is classified into 4 patterns based on mass and wall thickness. The geometric changes caused by maladaptation to pressure overload possibly relate to progression of contractile dysfunction with abnormal energy metabolism. The present study assessed whether the geometric adaptation of the left ventricle (LV) to high blood pressure relates to changes in myocardial energy metabolism, especially free fatty acid (FFA) utilization. Thirty-five patients with essential hypertension underwent echocardiography and dual isotopes myocardial scintigraphy using iodine-123 labeled 15-p-iodophenyl-3-(R,S)-methylpentadecanoic acid (BMIPP, an analogue of a FFA) and thallium-201 (Tl-201). Systolic (endocardial fractional shortening; %FS) and diastolic indices (the ratio of early to atrial filling waves; E/A) of LV function were also assessed. Quantitative myocardial BMIPP uptake was evaluated by the BMIPP/Tl-201 myocardial uptake ratio (B/T). The subjects were divided into 4 groups based on LV mass and wall thickness: concentric hypertrophy (CH), eccentric hypertrophy (EH), concentric remodeling (CR), and normal geometry (N). The %FS was lower in the EH group than in the other groups. The mitral E/A ratio in the CH group was lowest. B/T was significantly decreased in the EH group compared with the N group (p<0.05). B/T correlated with the mitral E/A ratio significantly (p<0.05, r=0.42), whereas there was no relationship between %FS and B/T. These results indicate that the geometric changes occurring in hypertensive hearts strongly correlate with alternations in cardiac function and with abnormal myocardial FFA metabolism, and that the latter is associated with diastolic abnormality, but not with systolic function. (author)

Validation of an in vitro contractility assay using canine ventricular myocytes

Energy Technology Data Exchange (ETDEWEB)

Harmer, A.R., E-mail: alex.harmer@astrazeneca.com; Abi-Gerges, N.; Morton, M.J.; Pullen, G.F.; Valentin, J.P.; Pollard, C.E.

2012-04-15

Measurement of cardiac contractility is a logical part of pre-clinical safety assessment in a drug discovery project, particularly if a risk has been identified or is suspected based on the primary- or non-target pharmacology. However, there are limited validated assays available that can be used to screen several compounds in order to identify and eliminate inotropic liability from a chemical series. We have therefore sought to develop an in vitro model with sufficient throughput for this purpose. Dog ventricular myocytes were isolated using a collagenase perfusion technique and placed in a perfused recording chamber on the stage of a microscope at ∼ 36 °C. Myocytes were stimulated to contract at a pacing frequency of 1 Hz and a digital, cell geometry measurement system (IonOptix™) was used to measure sarcomere shortening in single myocytes. After perfusion with vehicle (0.1% DMSO), concentration–effect curves were constructed for each compound in 4–30 myocytes taken from 1 or 2 dog hearts. The validation test-set was 22 negative and 8 positive inotropes, and 21 inactive compounds, as defined by their effect in dog, cynolomolgous monkey or humans. By comparing the outcome of the assay to the known in vivo contractility effects, the assay sensitivity was 81%, specificity was 75%, and accuracy was 78%. With a throughput of 6–8 compounds/week from 1 cell isolation, this assay may be of value to drug discovery projects to screen for direct contractility effects and, if a hazard is identified, help identify inactive compounds. -- Highlights: ► Cardiac contractility is an important physiological function of the heart. ► Assessment of contractility is a logical part of pre-clinical drug safety testing. ► There are limited validated assays that predict effects of compounds on contractility. ► Using dog myocytes, we have developed an in vitro cardiac contractility assay. ► The assay predicted the in vivo contractility with a good level of accuracy.

Cell therapy in myocardial infarction: emphasis on the role of MRI

International Nuclear Information System (INIS)

Ye, Yuxiang; Bogaert, Jan

2008-01-01

Despite tremendous progress in myocardial infarct (MI) treatment, mortality rates remain substantial. Permanent loss of cardiomyocytes after ischemic injury, results in irreversible loss of myocardial contractility, reduction in ventricular performance, and may initiate the development of dilated heart failure. The discovery that pluripotent progenitor cells bear the capacity to differentiate to mature cardiac cells raised the hope of cell-based regenerative medicine. Engraftment of stem cells in the damaged myocardium, repair and functional improvement appeared suddenly a nearby reality. Promising results in animal models, and preliminary studies reporting the feasibility and safety of adult stem cell therapy in MI patients led to the first double-blinded randomized, placebo-controlled trials. The initial great enthusiasm for this paradigm shift in MI treatment has been tempered by the mainly negative or modestly positive study findings. Before new, larger clinical trials can be initiated, a number of critical questions and issues need to be considered starting with a scrutinized analysis of currently available data to extending our knowledge of the mechanism of scarless myocardial regeneration. Cardiac cell therapy necessitates a multidisciplinary approach, whereby imaging, in particular MRI, and the input of the imaging specialist is crucial to the success of cardiac cell regenerative medicine. MRI is an appealing technique for cell trafficking depicting engraftment, differentiation and survival. Endomyocardial cell administration can be achieved safely with MR fluoroscopy and MRI is without any doubt the most accurate and reproducible technique to measure study end-points. (orig.)

Myocardial perfusion in silent myocardial ischemia

International Nuclear Information System (INIS)

Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa

1989-01-01

To investigate myocardial perfusion in silent myocardial ischemia, we performed exercise stress myocardial tomography with thallium-201 (Tl) in 85 patients with coronary artery disease (CAD). Exercise stress myocardial tomography was obtained both immediately after exercise and three hours later. Patients were classified into two groups according to the presence (Symptomatic Group, n=36) or absence (Silent Group, n=49) of chest pain during exercise stress. Clinical features (age, gender and history of myocardial infarction) and arteriographically determined severity of CAD were the same in both groups. The extent of myocardial ischemia (% Ischemia) estimated by exercise stress myocardial tomography was the same in each group (30±10 % in Silent Group, 28±12 % in Symptomatic Group, NS). The severity of exercise-induced myocardial ischemia was expressed as a minimal value of myocardial Tl washout rate (minimal WOR) of each patient. Although exercise heart rate was identical in both groups, minimal WOR in Silent Group was significantly higher than that of Symptomatic Group (4±10% vs -16±14%, p<0.001). The study in patients who exhibited both silent and symptomatic ischemia showed the same results. These findings suggest that the severity of ischemia is a fundamental factor in determining the presence or absence of pain during exercise induced ischemia. (author)

Permanent Distal Occlusion of Middle Cerebral Artery in Rat Causes Local Increased ETB, 5-HT1B and AT1 Receptor-Mediated Contractility Downstream of Occlusion

DEFF Research Database (Denmark)

Rasmussen, Marianne N P; Hornbak, Malene; Larsen, Stine S

2013-01-01

Background/Aims: In response to experimental stroke, a characteristic functional and expressional upregulation of contractile G-protein-coupled receptors has been uncovered in the affected cerebral vasculature; however, the mechanism initiating this phenomenon remains unknown. Methods: Using...... a model of permanent distal occlusion of rat middle cerebral arteries, we investigated whether there was a regional difference in receptor-mediated contractility of segments located upstream and downstream of the occlusion site. The contractile response to endothelin, angiotensin and 5-hydroxytryptamine...... receptor stimulation was studied by sensitive wire myograph. Results: Only downstream segments exhibited an augmented contractile response to stimulation with each of the three ligands, with the response towards sarafotoxin 6c being especially augmented compared to sham, upstream and contralateral controls...

Exercise and rest Tl-201 myocardial SPECT, and low dose dobutamine echocardiography to assess myocardial viability in patients with myocardial infarction

International Nuclear Information System (INIS)

Toyama, Takuji; Ishida, Yoshio; Shimonagata, Tsuyoshi; Kawano, Shigeo; Beppu, Shintaro; Nishimura, Tsunehiko.

1994-01-01

To evaluate viability of infarcted myocardium, findings of Tl-201 myocardial SPECT were compared with those of low-dose dobutamine (DOB) echocardiography. The subjects were 19 patients with myocardial infarction (23 infarcted zones), consisting of 16 men and 3 women. Findings on myocardial SPECT were classified as evidence of myocardial viability (14 zones, Group A) and no evidence of myocardial viability (9 zones, Group B). For both groups, wall motion and regional % uptake (%UP) were obtained. DOB echocardiography revealed an improvement in 5 of 8 akinesis zones in Group A. In addition, one other zone was found improved by follow-up examination. Six hypokinesis zones were all found improved on DOB echocardiography. Out of a total of 14 akinesis or hypokinesis zones, 11 (79%) showed improvement on DOB echocardiography in Group A. In Group B, all akinesis zones remained unchanged on DOB echocardiography, although one zone was improved by follow-up examination. In 11 zones in which wall motion was improved on DOB echocardiography, %UT was increased by an average of 58% on 4 hr-delayed images and 70% on resting images. The corresponding figures for 12 zones which did not improve on DOB echocardiography were 49% and 50% on the average, respectively. In conclusion, low-dose DOB echocardiography appeared to reflect viability of severely infarcted myocardium, although it had a slightly lower sensitivity than convensional Tl-201 myocardial SPECT in its ability to detect. (N.K.)

Blood pressure and the contractility of a human leg muscle.

Science.gov (United States)

Luu, Billy L; Fitzpatrick, Richard C

2013-11-01

These studies investigate the relationships between perfusion pressure, force output and pressor responses for the contracting human tibialis anterior muscle. Eight healthy adults were studied. Changing the height of tibialis anterior relative to the heart was used to control local perfusion pressure. Electrically stimulated tetanic force output was highly sensitive to physiological variations in perfusion pressure showing a proportionate change in force output of 6.5% per 10 mmHg. This perfusion-dependent change in contractility begins within seconds and is reversible with a 53 s time constant, demonstrating a steady-state equilibrium between contractility and perfusion pressure. These stimulated contractions did not produce significant cardiovascular responses, indicating that the muscle pressor response does not play a major role in cardiovascular regulation at these workloads. Voluntary contractions at forces that would require constant motor drive if perfusion pressure had remained constant generated a central pressor response when perfusion pressure was lowered. This is consistent with a larger cortical drive being required to compensate for the lost contractility with lower perfusion pressure. The relationship between contractility and perfusion for this large postural muscle was not different from that of a small hand muscle (adductor pollicis) and it responded similarly to passive peripheral and active central changes in arterial pressure, but extended over a wider operating range of pressures. If we consider that, in a goal-oriented motor task, muscle contractility determines central motor output and the central pressor response, these results indicate that muscle would fatigue twice as fast without a pressor response. From its extent, timing and reversibility we propose a testable hypothesis that this change in contractility arises through contraction- and perfusion-dependent changes in interstitial K(+) concentration.

Rationale and radiopharmaceuticals for myocardial imaging

International Nuclear Information System (INIS)

Poe, N.D.

1976-01-01

Static radionuclide imaging procedures are now available for evaluating regional myocardial perfusion and for detecting acute myocardial infarction. Thallium-201, a radiopharmaceutical which possesses many of the characteristics of potassium analogs, at present is receiving the greatest attention as a regional blood flow indicator. Ischemic lesions appear as areas of decreased tracer uptake. Unfortunately, this agent is expensive, is in limited supply and has a photopeak which is low for optimum imaging. Positive infarct images can be obtained with various technetium-99m chelates. Pyrophosphate appears to be the best of the technetium compounds studied to date although the mechanism of uptake of the chelates has not yet been fully elucidated. Therefore, quantitative measurements of infarct size are not justified. As perfusion imaging and infarct imaging provide useful, complementary data, a dual tracer approach to evaluating patients with suspected coronary artery disease and/or myocardial infarction is probably justifiable

Determination of multidirectional myocardial deformations in cats with hypertrophic cardiomyopathy by using two-dimensional speckle-tracking echocardiography.

Science.gov (United States)

Suzuki, Ryohei; Mochizuki, Yohei; Yoshimatsu, Hiroki; Teshima, Takahiro; Matsumoto, Hirotaka; Koyama, Hidekazu

2017-12-01

Objectives Hypertrophic cardiomyopathy, a primary disorder of the myocardium, is the most common cardiac disease in cats. However, determination of myocardial deformation with two-dimensional speckle-tracking echocardiography in cats with various stages of hypertrophic cardiomyopathy has not yet been reported. This study was designed to measure quantitatively multidirectional myocardial deformations of cats with hypertrophic cardiomyopathy. Methods Thirty-two client-owned cats with hypertrophic cardiomyopathy and 14 healthy cats serving as controls were enrolled and underwent assessment of myocardial deformation (peak systolic strain and strain rate) in the longitudinal, radial and circumferential directions. Results Longitudinal and radial deformations were reduced in cats with hypertrophic cardiomyopathy, despite normal systolic function determined by conventional echocardiography. Cats with severely symptomatic hypertrophic cardiomyopathy also had lower peak systolic circumferential strain, in addition to longitudinal and radial strain. Conclusions and relevance Longitudinal and radial deformation may be helpful in the diagnosis of hypertrophic cardiomyopathy. Additionally, the lower circumferential deformation in cats with severe hypertrophic cardiomyopathy may contribute to clinical findings of decompensation, and seems to be related to severe cardiac clinical signs. Indices of multidirectional myocardial deformations by two-dimensional speckle-tracking echocardiography may be useful markers and help to distinguish between cats with hypertrophic cardiomyopathy and healthy cats. Additionally, they may provide more detailed assessment of contractile function in cats with hypertrophic cardiomyopathy.

Influence of revascularization on myocardial perfusion, metabolism and function

International Nuclear Information System (INIS)

Kropp, Joachim; Krois, Markus; Eichhorn, Bernd; Fehske, Wolfgang; Likungu, James; Kirchhoff, P.G.; Luederitz, Berndt; Biersack, Hans-Juergen; Knapp, F.F. Jr.

1993-01-01

Thirty-nine patients with coronary artery disease (CAD) were investigated with sequential SPECT-scintigraphy after administration of 200 MBq of 15-(p-[I-123]iodophenyl)pentadecanoic acid (IPPA) at peak submaximal exercise. Twenty patients underwent coronary angioplasty (PTCA) from which 14 had control coronary arteriography (CA) and left ventricular cineventriculography (LVCV). Nineteen patients underwent bypass graft surgery (ACB) and stress sonography. Semi-quantification of uptake (Up, related to perfusion) and turnover (Tr, linked to metabolism) was obtained by segmental comparison of oblique slices. About 90% of the reperfused myocardial segments in the PTCA-group and 76% in the ACB-group showed an improvement of uptake after therapy (RUp). Out of these, 50% and 66% exhibited increased turnover (RTr) after PTCA or ACB, respectively. The remaining segments had persistingly pathologic RTr indicating a dissociation of improvement of perfusion and metabolism after therapy. Pathologic RTr was highly correlated with regional wall motion abnormalities (RWMA) after therapy in both groups. In the ACB-group improvement in RTr was correlated with improved RWM at rest and stress in 86% and 92%, respectively, whereas no improvement in RTr was correlated with impared function in 100% and 52%, respectively. IPPA-studies show potential to provide information about changes of perfusion and metabolism after reperfusion and IPPA-turnover is a good predictor of the pattern of contractile function. (author)

FDG F18/Rest Tl 201 SPECT patterns in recent myocardial infarction. Predictive value for regional function recovery

Energy Technology Data Exchange (ETDEWEB)

Massardo, Teresa [Universidad de Chile, Hospital Clinico. Centro de Medicina Nuclear, Santiago (Chile); Gonzalez, Patricio; Coll, Claudia; Yovanovich, Jorge; Jofre, M Josefina; Humeres, Pamela; Sierralta, Paulina; Chamorro, Hernan; Ramirez, Alfredo; Kunstmann, Sonia; Lopez, Hector; Aramburu, Ivonne; Bru, Solange [Universidad de Chile, Santiago (Chile). Hospital Clinico. Centros de Medicina Nuclear e Cardiovascular; Clinica Santa Maria, Santiago [Chile

2003-04-01

Background: detecting viability is important after recent myocardial infarction (MI). SPECT FDG/Tl flow-metabolism patterns for predicting functional recovery were analyzed in this setting. Method: forty-one patients were studied (56+-12 years; 80% males) with Tl 201 at rest and FDG F 18 SPECT at a mean of 8.9 days post MI (range:1-24). All had baseline and 3 month follow-up echocardiography (Echo) and initial coronary angiography. They were submitted to primary PTCA in 12 cases, late PTCA in 15 and bypass surgery in 10 and thrombolysis was performed in 4 patients as only procedure. A total of 345 culprit artery territory segments were interpreted by 3 nuclear independent observers. Analysis included segments with or without abnormal motion. Results: FDG/Tl 201 on patient basis, had: sensitivity 91%; specificity 56%; positive predictive value 88 %; negative predictive value (NPV) 63% and accuracy 83%. The analysis of segments with abnormal contractility showed values of 67%, 69%, 44%, 85% and 68%, respectively. Reverse mismatch with FDG/Tl appears to predict viability similarly to classical mismatch; severe or moderate match was highly associated with no functional recovery (NPV 85%). Conclusion: flow-perfusion patterns are variable in recent MI. FDG/Tl 201 SPECT has acceptable accuracy for predicting functional recovery and excellent NPV to further exclude viability (author)

FDG F18/Rest Tl 201 SPECT patterns in recent myocardial infarction. Predictive value for regional function recovery

International Nuclear Information System (INIS)

Massardo, Teresa; Gonzalez, Patricio; Coll, Claudia; Yovanovich, Jorge; Jofre, M. Josefina; Humeres, Pamela; Sierralta, Paulina; Chamorro, Hernan; Ramirez, Alfredo; Kunstmann, Sonia; Lopez, Hector; Aramburu, Ivonne; Bru, Solange; Clinica Santa Maria, Santiago

2003-01-01

Background: detecting viability is important after recent myocardial infarction (MI). SPECT FDG/Tl flow-metabolism patterns for predicting functional recovery were analyzed in this setting. Method: forty-one patients were studied (56+-12 years; 80% males) with Tl 201 at rest and FDG F 18 SPECT at a mean of 8.9 days post MI (range:1-24). All had baseline and 3 month follow-up echocardiography (Echo) and initial coronary angiography. They were submitted to primary PTCA in 12 cases, late PTCA in 15 and bypass surgery in 10 and thrombolysis was performed in 4 patients as only procedure. A total of 345 culprit artery territory segments were interpreted by 3 nuclear independent observers. Analysis included segments with or without abnormal motion. Results: FDG/Tl 201 on patient basis, had: sensitivity 91%; specificity 56%; positive predictive value 88 %; negative predictive value (NPV) 63% and accuracy 83%. The analysis of segments with abnormal contractility showed values of 67%, 69%, 44%, 85% and 68%, respectively. Reverse mismatch with FDG/Tl appears to predict viability similarly to classical mismatch; severe or moderate match was highly associated with no functional recovery (NPV 85%). Conclusion: flow-perfusion patterns are variable in recent MI. FDG/Tl 201 SPECT has acceptable accuracy for predicting functional recovery and excellent NPV to further exclude viability (author)

The expression of myocardial injury in cold induced myocardial imaging and echocardiography of systematic scleroderma

International Nuclear Information System (INIS)

Liang Jiugen; Zhu Xiaojun; Jiang Ningyi; Chen Shaoxiong

1999-01-01

The study was performed with cold-induced 99m Tc(MIBI) myocardial imaging (MI) in 23 patients with systematic scleroderma. The left ventricular function and wall motion were also observed by dimensional echocardiography (UCG). 14 patients had myocardial perfusion abnormalities visualized by MI, including 5 cases with fixed defects of 9 segments, 3 cases with reversible defects of 6 segments and 6 cases with both fixed and reversible one of 14 segments. The positive rate in myocardial imaging had no significant differences between patients with and without Raynaud's phenomenon (0.5>P>0.25). Compared with baseline, the ejection fraction, stroke volume, cardiac output were significantly decreased during cold-induced in patients with abnormal myocardial scintigraphy (P<0.05), and had significant difference compared with normal group (P<0.05). 4 cases with cold-induced reversible perfusion defects had anatomically correlated regional ventricular hypokinesia in UCG

Two-dimensional tracking and TDI are consistent methods for evaluating myocardial longitudinal peak strain in left and right ventricle basal segments in athletes

OpenAIRE

Lstefani, L.Stefani; Ltoncelli, L.Toncelli; Mgianassi, M.Gianassi; Pmanetti, P.Manetti; Vdi, V.Di Tante; Mrvono, M.R.Vono; Amoretti, A.Moretti; Bcappelli, B.Cappelli; Gpedrizzetti, G.Pedrizzetti; Ggalanti, G.Galanti

2007-01-01

Abstract Background Myocardial contractility can be investigated using longitudinal peak strain. It can be calculated using the Doppler-derived TDI method and the non-Doppler method based on tissue tracking on B-mode images. Both are validated and show good reproducibility, but no comparative analysis of their results has yet been conducted. This study analyzes the results obtained from the basal segments of the ventricular chambers in a group of athletes. Methods 30 regularly-trained athlete...

Comparison of contractile and extensile pneumatic artificial muscles

Science.gov (United States)

Pillsbury, Thomas E.; Wereley, Norman M.; Guan, Qinghua

2017-09-01

Pneumatic artificial muscles (PAMs) are used in robotic and prosthetic applications due to their high power to weight ratio, controllable compliance, and simple design. Contractile PAMs are typically used in traditional hard robotics in place of heavy electric motors. As the field of soft robotics grows, extensile PAMs are beginning to have increased usage. This work experimentally tests, models, and compares contractile and extensile PAMs to demonstrate the advantages and disadvantages of each type of PAM and applications for which they are best suited.

Myocardial turnover rates of I-123 heptadecanoic acid (HDA)

International Nuclear Information System (INIS)

Dudczak, R.; Schmoliner, R.; Kletter, K.; Derfler, D.K.; Frischauf, H.; Angelberger, P.; Losert, U.

1982-01-01

Myocardial scintigraphy was performed with I-123 labeled HDA in patients with coronary artery disease (CAD, n=37), cardiomyopathy (COCM, n=7) and controls (n=10). These results were compared with coronary angiography, Tl 201 scintigraphy and radionuclide angiography. Results from animal experiments (intracoronary application in calfes) and patient studies supported the assumption that myocardial scintigraphy with I-123 HDA reveals information about myocardial fatty acid utilisation. Summarizing all clinical results using I-123 HDA showed that from the myocardial accumulation pattern of the labeled fatty acid, as well as from Tl 201 perfusion scintigraphy, the value of the regional elimination rate (t/2) could not be predicted. In patients with COCM the mean t/2 was prolonged, but overlapped with controls. In ischemic regions ''shortened'', normal and prolonged elimination rates were found. These findings were related to the observed wall motion and the calculated regional ejection fraction (r=0.73, p<0.001). This data indicate, that I-123 HDA add a further aspect in nuclear cardiology; the results obtained bear a relation to the functional state of the diseased heart

Stalk-length-dependence of the contractility of Vorticella convallaria

Science.gov (United States)

Gul Chung, Eun; Ryu, Sangjin

2017-12-01

Vorticella convallaria is a sessile protozoan of which the spasmoneme contracts on a millisecond timescale. Because this contraction is induced and powered by the binding of calcium ions (Ca2+), the spasmoneme showcases Ca2+-powered cellular motility. Because the isometric tension of V. convallaria increases linearly with its stalk length, it is hypothesized that the contractility of V. convallaria during unhindered contraction depends on the stalk length. In this study, the contractile force and energetics of V. convallaria cells of different stalk lengths were evaluated using a fluid dynamic drag model which accounts for the unsteadiness and finite Reynolds number of the water flow caused by contracting V. convallaria and the wall effect of the no-slip substrate. It was found that the contraction displacement, peak contraction speed, peak contractile force, total mechanical work, and peak power depended on the stalk length. The observed stalk-length-dependencies were simulated using a damped spring model, and the model estimated that the average spring constant of the contracting stalk was 1.34 nN µm-1. These observed length-dependencies of Vorticella’s key contractility parameters reflect the biophysical mechanism of the spasmonemal contraction, and thus they should be considered in developing a theoretical model of the Vorticella spasmoneme.

Inhibition of isolated human myometrium contractility by minoxidil and reversal by glibenclamide.

Science.gov (United States)

Prabhakaran, S S; Dhanasekar, K R; Thomas, E; Jose, R; Peedicayil, J; Samuel, P

2010-03-01

This study investigated the ability of the antihypertensive drug minoxidil to inhibit potassium chloride (KCl)-induced contractility of the isolated human myometrium. Twelve strips of myometrium obtained from 12 patients who underwent hysterectomy were triggered to contract with 55 mM KCl before and after incubation with 3 concentrations (1, 3 and 10 microM) of minoxidil. The percent inhibition by minoxidil on the extent of contraction, and the area under the contractile curve of KCl-induced contraction of the myometrial strips was determined. Furthermore, the effect of 10 microM glibenclamide on the inhibition generated by 3 microM minoxidil on KCl-induced contractility was studied. It was found that minoxidil produced a concentration-dependent inhibition of KCl-induced contractility of the myometrium and that glibenclamide reversed this inhibitory effect. These results suggest that the inhibitory effect of minoxidil on isolated human myometrium contractility may prove useful in clinical conditions requiring relaxation of the myometrium. 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

Myocardial Infarction Causes Transient Cholinergic Transdifferentiation of Cardiac Sympathetic Nerves via gp130.

Science.gov (United States)

Olivas, Antoinette; Gardner, Ryan T; Wang, Lianguo; Ripplinger, Crystal M; Woodward, William R; Habecker, Beth A

2016-01-13

Sympathetic and parasympathetic control of the heart is a classic example of norepinephrine (NE) and acetylcholine (ACh) triggering opposing actions. Sympathetic NE increases heart rate and contractility through activation of β receptors, whereas parasympathetic ACh slows the heart through muscarinic receptors. Sympathetic neurons can undergo a developmental transition from production of NE to ACh and we provide evidence that mouse cardiac sympathetic nerves transiently produce ACh after myocardial infarction (MI). ACh levels increased in viable heart tissue 10-14 d after MI, returning to control levels at 21 d, whereas NE levels were stable. At the same time, the genes required for ACh synthesis increased in stellate ganglia, which contain most of the sympathetic neurons projecting to the heart. Immunohistochemistry 14 d after MI revealed choline acetyltransferase (ChAT) in stellate sympathetic neurons and vesicular ACh transporter immunoreactivity in tyrosine hydroxylase-positive cardiac sympathetic fibers. Finally, selective deletion of the ChAT gene from adult sympathetic neurons prevented the infarction-induced increase in cardiac ACh. Deletion of the gp130 cytokine receptor from sympathetic neurons prevented the induction of cholinergic genes after MI, suggesting that inflammatory cytokines induce the transient acquisition of a cholinergic phenotype in cardiac sympathetic neurons. Ex vivo experiments examining the effect of NE and ACh on rabbit cardiac action potential duration revealed that ACh blunted both the NE-stimulated decrease in cardiac action potential duration and increase in myocyte calcium transients. This raises the possibility that sympathetic co-release of ACh and NE may impair adaptation to high heart rates and increase arrhythmia susceptibility. Sympathetic neurons normally make norepinephrine (NE), which increases heart rate and the contractility of cardiac myocytes. We found that, after myocardial infarction, the sympathetic neurons

Abnormal myocardial free fatty acid utilization deteriorates with morphological changes in the hypertensive heart

Energy Technology Data Exchange (ETDEWEB)

Nakayama, Hiroyuki; Morozumi, Takakazu; Nanto, Shinsuke [Kansai Rosai Hospital, Amagasaki, Hyogo (Japan)] (and others)

2001-09-01

The left ventricle's morphological adaptation to high blood pressure is classified into 4 patterns based on mass and wall thickness. The geometric changes caused by maladaptation to pressure overload possibly relate to progression of contractile dysfunction with abnormal energy metabolism. The present study assessed whether the geometric adaptation of the left ventricle (LV) to high blood pressure relates to changes in myocardial energy metabolism, especially free fatty acid (FFA) utilization. Thirty-five patients with essential hypertension underwent echocardiography and dual isotopes myocardial scintigraphy using iodine-123 labeled 15-p-iodophenyl-3-(R,S)-methylpentadecanoic acid (BMIPP, an analogue of a FFA) and thallium-201 (Tl-201). Systolic (endocardial fractional shortening; %FS) and diastolic indices (the ratio of early to atrial filling waves; E/A) of LV function were also assessed. Quantitative myocardial BMIPP uptake was evaluated by the BMIPP/Tl-201 myocardial uptake ratio (B/T). The subjects were divided into 4 groups based on LV mass and wall thickness: concentric hypertrophy (CH), eccentric hypertrophy (EH), concentric remodeling (CR), and normal geometry (N). The %FS was lower in the EH group than in the other groups. The mitral E/A ratio in the CH group was lowest. B/T was significantly decreased in the EH group compared with the N group (p<0.05). B/T correlated with the mitral E/A ratio significantly (p<0.05, r=0.42), whereas there was no relationship between %FS and B/T. These results indicate that the geometric changes occurring in hypertensive hearts strongly correlate with alternations in cardiac function and with abnormal myocardial FFA metabolism, and that the latter is associated with diastolic abnormality, but not with systolic function. (author)

Cine MR imaging assessment of regional left ventricular systolic wall thickening in patients with remote myocardial infarction

International Nuclear Information System (INIS)

Pfugfelder, P.; White, R.D.; Sechtem, U.; Gould, R.G.; Higgins, C.B.

1986-01-01

Cine MR imaging, a new rapid imaging technique, was used to acquire transverse images of the heart at a rate of 16-30 frames per cardiac cycle. Left ventricular wall thickness was measured at end diastole and end systole in six regions in the midventricular section of 13 healthy subjects and seven patients with previously documented myocardial infarction. Mean percent systolic wall thickening (%SWT) was 51% +- 26% in healthy subjects. In patients, %SWT was -8% +- 22% in the infarct zone and 42% +- 22% in the normal myocardium. In addition to the qualitative information derived from the cinematic display, determination of regional %SWT by cine-MR imaging may be useful for quantifying regional left ventricular dysfunction

Association of myocardial inotropic reserve and adrenergic nerve alterations in idiopathic dilated cardiomyopathy. A dobutamine stress echocardiographic and 123-I-MIBG scintigraphic study

International Nuclear Information System (INIS)

Prassopoulos, V.P.; Koukouraki, S.; Velidaki, A.; Karkavitsas, N.; Parthenakis, F.; Patrianakos, A.; Kochiadakis, G.; Papadimitriou, E.; Vardas, P.

2002-01-01

Aim: Evaluation of contractile reserve is important in congestive hear failure. The aim of this study was to examine the relationship between the myocardial response to dobutamine by stress echocardiography and the sympathetic nerve alterations by 123-I-Metaiodobenzylguanidine (MIBG)scintigraphy and how both contribute to predict exercise capacity in patients with idiopathic dilated cardiomyopathy. Materials-Methods: We studied 20 patients with idiopathic dilated cardiomyopathy (IDC) and ejection fraction < 45% (M/F 13/7, age 56±11 years) while 15 healthy individuals served as controls. Echocardiography and myocardial scintigraphic study with 123-I- MIBG, provided quantitative assessment of left ventricular (LV) wall motion and heart to mediastinum uptake(H/M) ratio and washout. All patients underwent a cardiopulmonary exercise test with a modified Naughton protocol and gas exchange data were analyzed. According to LV response to dobutamine, patients were divided into two groups: those in whom contractility improved in ≥ five segments (Group I: 11 patients) and those in whom contractility improved in < 5 segments (Group II : 9 patients). Results: MIBG uptake was significantly lower in patients than in controls (p < 0.001). MIBG uptake and washout was higher in Group I compared to Group II (P<0,01 and p<0,05). Late MIBG H/M was correlated with resting ejection fraction (r=0,70), wall motion score index (WMSI) (r=-0,50), end systolic wall stress (r=-0,61), washout (r=-0,57), and oxygen consumption at peak exercise (r=0,64) and at anaerobic threshold (r=0,67). LV ejection fraction increased in both groups at Dobutamine, with a higher increase in Group I (p=0,008). WMSI changes at dobutamine correlated significantly with resting ejection fraction (r=0,46) early (r=0,53) and late (r=0,54) MIBG. Multivariate analysis revealed that only the late MIBG uptake was independently associated with the improvement in WMSI. Conclusions: The present data indicate that in

Summation and Cancellation Effects on QRS and ST-Segment Changes Induced by Simultaneous Regional Myocardial Ischemia.

Science.gov (United States)

Vives-Borrás, Miquel; Jorge, Esther; Amorós-Figueras, Gerard; Millán, Xavier; Arzamendi, Dabit; Cinca, Juan

2018-01-01

Simultaneous ischemia in two myocardial regions is a potentially lethal clinical condition often unrecognized whose corresponding electrocardiographic (ECG) patterns have not yet been characterized. Thus, this study aimed to determine the QRS complex and ST-segment changes induced by concurrent ischemia in different myocardial regions elicited by combined double occlusion of the three main coronary arteries. For this purpose, 12 swine were randomized to combination of 5-min single and double coronary artery occlusion: Group 1: left Circumflex (LCX) and right (RCA) coronary arteries ( n = 4); Group 2: left anterior descending artery (LAD) and LCX ( n = 4) and; Group 3: LAD and RCA ( n = 4). QRS duration and ST-segment displacement were measured in 15-lead ECG. As compared with single occlusion, double LCX+RCA blockade induced significant QRS widening of about 40 ms in nearly all ECG leads and magnification of the ST-segment depression in leads V1-V3 (maximal 228% in lead V3, p ST-segment elevation in precordial leads (maximal attenuation of 60% in lead V3 in LAD+LCX and 86% in lead V5 in LAD+RCA, p ST-segment elevation in leads V7-V9 was a specific sign of single LCX occlusion. In conclusion, concurrent infero-lateral ischemia was associated with a marked summation effect of the ECG changes previously elicited by each single ischemic region. By contrast, a cancellation effect on ST-segment changes with no QRS widening was observed when the left anterior descending artery was involved.

Actomyosin contractility rotates the cell nucleus.

Science.gov (United States)

Kumar, Abhishek; Maitra, Ananyo; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G V

2014-01-21

The cell nucleus functions amidst active cytoskeletal filaments, but its response to their contractile stresses is largely unexplored. We study the dynamics of the nuclei of single fibroblasts, with cell migration suppressed by plating onto micro-fabricated patterns. We find the nucleus undergoes noisy but coherent rotational motion. We account for this observation through a hydrodynamic approach, treating the nucleus as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and coherence of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic flow around the nucleus, with profile and magnitude consistent with the results of our theoretical approach. Coherent intracellular flows and consequent nuclear rotation thus appear to be an intrinsic property of cells.

The thallium-201 myocardial scintigraphy, its possibilities and limitations

International Nuclear Information System (INIS)

Adam, W.; Meindl, S.; Schmitz, A.; Utech, C.; Boettcher, D.

1983-01-01

The Thallium-201 Myocardial Scintigraphy, its Possibilities and limitations: The Thallium-201 myocardial scintigraphy is a simple non-invasive procedure to detect hypo- and non-perfused myocardial regions. In the he last years it was demonstrated to be a helpful method in the diagnostic strategy for the cardiologist. It can not replace the coronary angiogram, but in many cases it appears to be useful in selecting patients for coronary angiography. (orig.) [de

Normal values of regional left ventricular myocardial thickness, mass and distribution-assessed by 320-detector computed tomography angiography in the Copenhagen General Population Study

DEFF Research Database (Denmark)

Hindsø, Louise; Fuchs, Andreas; Kühl, Jørgen Tobias

2017-01-01

regional normal reference values of the left ventricle. The aim of this study was to derive reference values of regional LV myocardial thickness (LVMT) and mass (LVMM) from a healthy study group of the general population using cardiac computed tomography angiography (CCTA). We wanted to introduce LV...... myocardial distribution (LVMD) as a measure of regional variation of the LVMT. Moreover, we wanted to determine whether these parameters varied between men and women. We studied 568 (181 men; 32%) adults, free of cardiovascular disease and risk factors, who underwent 320-detector CCTA. Mean age was 55 (range...... 40-84) years. Regional LVMT and LVMM were measured, according to the American Heart Association's 17 segment model, using semi-automatic software. Mean LVMT were 6.6 mm for men and 5.4 mm for women (p normal LV was thickest in the basal septum (segment 3; men = 8.3 mm; women = 7.2 mm...

Slack length reduces the contractile phenotype of the Swine carotid artery.

Science.gov (United States)

Rembold, Christopher M; Garvey, Sean M; Tejani, Ankit D

2013-01-01

Contraction is the primary function of adult arterial smooth muscle. However, in response to vessel injury or inflammation, arterial smooth muscle is able to phenotypically modulate from the contractile state to several 'synthetic' states characterized by proliferation, migration and/or increased cytokine secretion. We examined the effect of tissue length (L) on the phenotype of intact, isometrically held, initially contractile swine carotid artery tissues. Tissues were studied (1) without prolonged incubation at the optimal length for force generation (1.0 Lo, control), (2) with prolonged incubation for 17 h at 1.0 Lo, or (3) with prolonged incubation at slack length (0.6 Lo) for 16 h and then restoration to 1.0 Lo for 1 h. Prolonged incubation at 1.0 Lo minimally reduced the contractile force without substantially altering the mediators of contraction (crossbridge phosphorylation, shortening velocity or stimulated actin polymerization). Prolonged incubation of tissues at slack length (0.6 Lo), despite return of length to 1.0 Lo, substantially reduced contractile force, reduced crossbridge phosphorylation, nearly abolished crossbridge cycling (shortening velocity) and abolished stimulated actin polymerization. These data suggest that (1) slack length treatment significantly alters the contractile phenotype of arterial tissue, and (2) slack length treatment is a model to study acute phenotypic modulation of intact arterial smooth muscle. Copyright © 2013 S. Karger AG, Basel.

Improved exercise myocardial perfusion during lidoflazine therapy

International Nuclear Information System (INIS)

Shapiro, W.; Narahara, K.A.; Park, J.

1983-01-01

Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise

Myocardial Bridge

Science.gov (United States)

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Calcium-responsive contractility during fertilization in sea urchin eggs.

Science.gov (United States)

Stack, Christianna; Lucero, Amy J; Shuster, Charles B

2006-04-01

Fertilization triggers a reorganization of oocyte cytoskeleton, and in sea urchins, there is a dramatic increase in cortical F-actin. However, the role that myosin II plays during fertilization remains largely unexplored. Myosin II is localized to the cortical cytoskeleton both before and after fertilization and to examine myosin II contractility in living cells, Lytechinus pictus eggs were observed by time-lapse microscopy. Upon sperm binding, a cell surface deflection traversed the egg that was followed by and dependent on the calcium wave. The calcium-dependence of surface contractility could be reproduced in unfertilized eggs, where mobilization of intracellular calcium in unfertilized eggs under compression resulted in a marked contractile response. Lastly, inhibition of myosin II delayed absorption of the fertilization cone, suggesting that myosin II not only responds to the same signals that activate eggs but also participates in the remodeling of the cortical actomyosin cytoskeleton during the first zygotic cell cycle. (c) 2006 Wiley-Liss, Inc.

Positron imaging in the evaluation of ischemia and myocardial infarction

International Nuclear Information System (INIS)

Goldstein, R.A.

1985-01-01

Positron emission tomography (PET) is a unique imaging approach since it allows quantification of regional myocardial radioactivity by virtue of its decay characteristics. Studies of regional myocardial metabolism are possible since there are positron emitting isotopes of carbon, oxygen and nitrogen that can be used to synthesize labeled fatty acids, amino acids or carbohydrate. Recent studies from the author's group have focused on Rb-82, a diffusible cation with a short half-life that is obtained from a generator and thus, has the potential for routine clinical use without a cyclotron. In this chapter, the basic principles of positron imaging and their application to imaging of acute myocardial infarction are discussed

17 alpha-hydroxyprogesterone caproate vehicle, castor oil, enhances the contractile effect of oxytocin in human myometrium in pregnancy.

Science.gov (United States)

O'Sullivan, Michael D; Hehir, Mark P; O'Brien, Yvonne M; Morrison, John J

2010-05-01

The possibility exists that the vehicle for 17-alpha-hydroxyprogesterone caproate, castor oil, exerts an effect on human uterine contractility. The aim of this study was to evaluate its effects on contractility of myometrial preparations that were obtained during pregnancy. Myometrial strips were suspended under isometric conditions. Contractility was induced with oxytocin. Strips were incubated in castor oil or physiologic salt solution and suspended for a further oxytocin challenge. Contractile integrals were compared between both groups. Strips that were exposed to castor oil demonstrated increased contractile activity that was elicited by oxytocin (mean contractility value, 165.53%+/-17.03%; n=8; P=.004), compared with control strips (mean contractility value, 72.57%+/-7.48%; n=8; P=.003). There was a significant increase in contractile activity of the castor oil-exposed strips, compared with those that were exposed to physiologic salt solution (n=8; Pcastor oil results in enhanced oxytocin-induced contractility. Copyright (c) 2010 Mosby, Inc. All rights reserved.

[Association between collateral circulation and myocardial viability evaluated by cardiac magnetic resonance imaging in patients with coronary artery chronic total occlusion].

Science.gov (United States)

Li, J N; Zhang, L J; He, Y; Chen, Y L; Huang, R C; Lyu, S Z; Song, X T

2017-07-24

Objective: Late gadolinium enhancement(LGE) cardiac magnetic resonance imaging(CMR) was used to evaluate the myocardial viability of chronic total occlusion(CTO) in patients with coronary heart disease and to observe the relationship between collateral circulation and myocardium viability in these patients. Methods: This retrospective study included 40 patients with CTO diagnosed by invasive coronary angiography (CAG) from September 2015 to June 2016 in our department, all patients performed CMR examination within one week after CAG.The collateral circulation of CTO was graded with Rentrop classification as follows: poor or no collateral circulation group, moderate collateral circulation group and good collateral circulation group.According to CMR images, the delayed enhancement transmural extent of myocardial segments were scored, the ventricular wall motion of the myocardial segment were graded, and the wall motion score index (WMSI) was calculated.Spearman correlation analysis was used to analyze the relationship between the delayed enhancement transmural extent of myocardial segments and WMSI. Results: In the no or poor collateral group of 6 myocardial regions, 1 myocardial region had viable myocardium and 3 myocardial regions had no viable myocardium; in the moderate collateral group of 16 myocardial regions, 11 myocardial regions had viable myocardium and 5 myocardial regions had no viable myocardium; in the good collateral group of 24 myocardial regions, 21 myocardial regions had viable myocardium and 3 myocardial regions had no viable myocardium, there was significant difference between the groups ( P =0.002). The WMSI of poor or no collateral circulation group, moderate collateral circulation group and good collateral circulation group were 1.54±0.50, 1.21±0.34 and 1.26±0.40, respectively, there was no significant difference between the groups ( P =0.063). Spearman correlation analysis showed that the extent of delayed enhancement transmural extent of

Attenuation correction of myocardial SPECT by scatter-photopeak window method in normal subjects

International Nuclear Information System (INIS)

Okuda, Koichi; Nakajima, Kenichi; Matsuo, Shinro; Kinuya, Seigo; Motomura, Nobutoku; Kubota, Masahiro; Yamaki, Noriyasu; Maeda, Hisato

2009-01-01

Segmentation with scatter and photopeak window data using attenuation correction (SSPAC) method can provide a patient-specific non-uniform attenuation coefficient map only by using photopeak and scatter images without X-ray computed tomography (CT). The purpose of this study is to evaluate the performance of attenuation correction (AC) by the SSPAC method on normal myocardial perfusion database. A total of 32 sets of exercise-rest myocardial images with Tc-99m-sestamibi were acquired in both photopeak (140 keV±10%) and scatter (7% of lower side of the photopeak window) energy windows. Myocardial perfusion databases by the SSPAC method and non-AC (NC) were created from 15 female and 17 male subjects with low likelihood of cardiac disease using quantitative perfusion SPECT software. Segmental myocardial counts of a 17-segment model from these databases were compared on the basis of paired t test. AC average myocardial perfusion count was significantly higher than that in NC in the septal and inferior regions (P<0.02). On the contrary, AC average count was significantly lower in the anterolateral and apical regions (P<0.01). Coefficient variation of the AC count in the mid, apical and apex regions was lower than that of NC. The SSPAC method can improve average myocardial perfusion uptake in the septal and inferior regions and provide uniform distribution of myocardial perfusion. The SSPAC method could be a practical method of attenuation correction without X-ray CT. (author)

Neuroanatomic correlates of stroke-related myocardial injury.

Science.gov (United States)

Ay, H; Koroshetz, W J; Benner, T; Vangel, M G; Melinosky, C; Arsava, E M; Ayata, C; Zhu, M; Schwamm, L H; Sorensen, A G

2006-05-09

Myocardial injury can occur after ischemic stroke in the absence of primary cardiac causes. The neuroanatomic basis of stroke-related myocardial injury is not well understood. To identify regions of brain infarction associated with myocardial injury using a method free of the bias of an a priori hypothesis as to any specific location. Of 738 consecutive patients with acute ischemic stroke, the authors identified 50 patients in whom serum cardiac troponin T (cTnT) elevation occurred in the absence of any apparent cause within 3 days of symptom onset. Fifty randomly selected, age- and sex-matched patients with ischemic stroke without cTnT elevation served as controls. Diffusion-weighted images with outlines of infarction were co-registered to a template, averaged, and then subtracted to find voxels that differed between the two groups. Voxel-wise p values were determined using a nonparametric permutation test to identify specific regions of infarction that were associated with cTnT elevation. The study groups were well balanced with respect to stroke risk factors, history of coronary artery disease, infarction volume, and frequency of right and left middle cerebral artery territory involvement. Brain regions that were a priori associated with cTnT elevation included the right posterior, superior, and medial insula and the right inferior parietal lobule. Among patients with right middle cerebral artery infarction, the insular cluster was involved in 88% of patients with and 33% without cTnT elevation (odds ratio: 15.00; 95% CI: 2.65 to 84.79). Infarctions in specific brain regions including the right insula are associated with elevated serum cardiac troponin T level indicative of myocardial injury.

Free radicals in hypoxic rat diaphragm contractility: no role for xanthine oxidase.

NARCIS (Netherlands)

Heunks, L.M.A.; Machiels, H.A.; Abreu, R.A. de; Zhu, X.; Heijden, E. van der; Dekhuijzen, P.N.R.

2001-01-01

Recent evidence indicates that hypoxia enhances the generation of oxidants. Little is known about the role of free radicals in contractility of the rat diaphragm during hypoxia. We hypothesized that antioxidants improve contractility of the hypoxic rat diaphragm and that xanthine oxidase (XO) is an

Contractility of the guinea pig bladder measured in situ and in vitro

NARCIS (Netherlands)

J.M. Groen (Jan); R. van Mastrigt (Ron); J.L.H.R. Bosch (Ruud)

1994-01-01

textabstractTo study the relative importance of neurogenic factors in detrusor contractility and to relate a total bladder in vitro contractility model to a previously described bladder wall strip model, active intravesical pressure values were compared in situ and in vitro in eight male guinea

Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects

DEFF Research Database (Denmark)

Kofoed, Klaus F; Hove, Jens D; Freiberg, Jacob

2002-01-01

The aim of this study was to assess regional and global variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects and to evaluate potentially responsible factors. Twenty men with a mean age of 64 years, no history of cardiovascular disease, and normal blood pressure...... rest and hyperaemic blood flow during dipyridamole infusion were measured with nitrogen-13 ammonia and positron emission tomography in 16 left ventricular myocardial segments. Intra-individual and inter-individual variability of insulin-stimulated myocardial glucose uptake [relative dispersion...... = (standard deviation/mean)] was 13% and 29% respectively. Although inter-individual variability of glucose uptake and blood flow at rest was of the same magnitude, no correlation was found between these measures. Regional and global insulin-stimulated myocardial glucose uptake correlated linearly with whole...

Left Ventricular Myocardial Function in Children With Pulmonary Hypertension: Relation to Right Ventricular Performance and Hemodynamics.

Science.gov (United States)

Burkett, Dale A; Slorach, Cameron; Patel, Sonali S; Redington, Andrew N; Ivy, D Dunbar; Mertens, Luc; Younoszai, Adel K; Friedberg, Mark K

2015-08-01

Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that LV strain/strain rate, surrogate measures of myocardial contractility, are reduced in pediatric PH and relate to invasive hemodynamics, right ventricular strain, and functional measures of PH. At 2 institutions, echocardiography was prospectively performed in 54 pediatric PH patients during cardiac catheterization, and in 54 matched controls. Patients with PH had reduced LV global longitudinal strain (LS; -18.8 [-17.3 to -20.4]% versus -20.2 [-19.0 to -20.9]%; P=0.0046) predominantly because of reduced basal (-12.9 [-10.8 to -16.3]% versus -17.9 [-14.5 to -20.7]%; Pright ventricular free-wall LS (r=0.64; PBrain natriuretic peptide levels correlated moderately with septal LS (r=0.48; P=0.0038). PH functional class correlated moderately with LV free-wall LS (r=-0.48; P=0.0051). The septum, shared between ventricles and affected by septal shift, was the most affected LV region in PH. Pediatric PH patients demonstrate reduced LV strain/strain rate, predominantly within the septum, with relationships to invasive hemodynamics, right ventricular strain, and functional PH measures. © 2015 American Heart Association, Inc.

Myocardial ischemia and angina pectoris. The clinical problem in patients

Energy Technology Data Exchange (ETDEWEB)

Selwyn, A.P.; Fox, K.M.; Jonathan, A.; Lavender, P.; Watson, I.

1981-02-01

Ambulatory monitoring of ST segment changes was performed in 60 patients presenting with angina, positive ECG stress tests and coronary artery disease, 85% of ischemic ECG events were asymptomatic, 37% occurred with no increase in heart rate and 15% of episodes either lasted 20 minutes or more or fluctuated in severity. A controlled pilot study in ten patients showed depression. Radionuclide studies in 50 patients with angina and coronary artery disease have shown that stress (i.e., atrial pacing) produced different patterns of disturbed regional myocardial perfusion related to the patient's exercise capacity and eventually leading to a decrease in regional myocardial perfusion during the ischemic episode. ST segment depression appeared only after the decrease in regional myocardial perfusion. These findings combined with past research suggest that patients with angina and coronary artery disease can suffer frequent asymptomatic disturbances of the regional myocardial perfusion. The frequency of these episodes and the time course for the recovery of the metabolic consequences mean that segments of ventricular myocardium may be constantly abnormal. The relative importance of changes in coronary tone and malfunction of platelets in the diseased coronary tree needs to be examined in clinical research. Pilot studies of antiplatelet agents have shown a significant beneficial effect on episodes of ischemia occurring at night and those occurring without any increase in heart rate. The techniques and observations in these patients with coronary artery disease all suggest that acute transient regional myocardial ischemia is caused by a variety of mechanisms. Further research using objective methods is required to discover the causes of ischemia and to rationalize treatment.

Spontaneous actin dynamics in contractile rings

Science.gov (United States)

Kruse, Karsten; Wollrab, Viktoria; Thiagarajan, Raghavan; Wald, Anne; Riveline, Daniel

Networks of polymerizing actin filaments are known to be capable to self-organize into a variety of structures. For example, spontaneous actin polymerization waves have been observed in living cells in a number of circumstances, notably, in crawling neutrophils and slime molds. During later stages of cell division, they can also spontaneously form a contractile ring that will eventually cleave the cell into two daughter cells. We present a framework for describing networks of polymerizing actin filaments, where assembly is regulated by various proteins. It can also include the effects of molecular motors. We show that the molecular processes driven by these proteins can generate various structures that have been observed in contractile rings of fission yeast and mammalian cells. We discuss a possible functional role of each of these patterns. The work was supported by Agence Nationale de la Recherche, France, (ANR-10-LABX-0030-INRT) and by Deutsche Forschungsgemeinschaft through SFB1027.

Cold stress accentuates pressure overload-induced cardiac hypertrophy and contractile dysfunction: role of TRPV1/AMPK-mediated autophagy.

Science.gov (United States)

Lu, Songhe; Xu, Dezhong

2013-12-06

Severe cold exposure and pressure overload are both known to prompt oxidative stress and pathological alterations in the heart although the interplay between the two remains elusive. Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel activated in response to a variety of exogenous and endogenous physical and chemical stimuli including heat and capsaicin. The aim of this study was to examine the impact of cold exposure on pressure overload-induced cardiac pathological changes and the mechanism involved. Adult male C57 mice were subjected to abdominal aortic constriction (AAC) prior to exposure to cold temperature (4 °C) for 4 weeks. Cardiac geometry and function, levels of TRPV1, mitochondrial, and autophagy-associated proteins including AMPK, mTOR, LC3B, and P62 were evaluated. Sustained cold stress triggered cardiac hypertrophy, compromised depressed myocardial contractile capacity including lessened fractional shortening, peak shortening, and maximal velocity of shortening/relengthening, enhanced ROS production, and mitochondrial injury, the effects of which were negated by the TRPV1 antagonist SB366791. Western blot analysis revealed upregulated TRPV1 level and AMPK phosphorylation, enhanced ratio of LC3II/LC3I, and downregulated P62 following cold exposure. Cold exposure significantly augmented AAC-induced changes in TRPV1, phosphorylation of AMPK, LC3 isoform switch, and p62, the effects of which were negated by SB366791. In summary, these data suggest that cold exposure accentuates pressure overload-induced cardiac hypertrophy and contractile defect possibly through a TRPV1 and autophagy-dependent mechanism. Copyright © 2013. Published by Elsevier Inc.

PHARMACOEPIDEMIOLOGIC ANALYSIS OF ST-ELEVATION MYOCARDIAL INFARCTION REPERFUSION THERAPY AT SARATOV REGION HOSPITALS OF DIFFERENT TYPES

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O. V. Reshetko

2016-01-01

Full Text Available Aim. To evaluate the real practice of thrombolytic therapy of patients with ST-elevation myocardial infarction (STEMI at cardiological departments of Saratov and Saratov region hospitals.Material and methods. Retrospective pharmacoepidemiologic study was carried out. Case histories of STEMI patients discharged from cardiologic departments of several central district hospitals (CDH of Saratov region, cardiologic department of one of Saratov general municipal hospitals (MH and urgent cardiology department of Saratov clinical hospital (CH in 2006 were analyzed.Results. In CH all patients received thrombolytic therapy given they did not have contraindications and were admitted to the hospital timely. Few patients received thrombolytic therapy in MH and CDH in 2006.Conclusion. Correlation between hospital type and quality of STEMI management has been revealed.

Deletion of protein tyrosine phosphatase 1B rescues against myocardial anomalies in high fat diet-induced obesity: Role of AMPK-dependent autophagy.

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Kandadi, Machender R; Panzhinskiy, Evgeniy; Roe, Nathan D; Nair, Sreejayan; Hu, Dahai; Sun, Aijun

2015-02-01

Obesity-induced cardiomyopathy may be mediated by alterations in multiple signaling cascades involved in glucose and lipid metabolism. Protein tyrosine phosphatase-1B (PTP1B) is an important negative regulator of insulin signaling. This study was designed to evaluate the role of PTP1B in high fat diet-induced cardiac contractile anomalies. Wild-type and PTP1B knockout mice were fed normal (10%) or high (45%) fat diet for 5months prior to evaluation of cardiac function. Myocardial function was assessed using echocardiography and an Ion-Optix MyoCam system. Western blot analysis was employed to evaluate levels of AMPK, mTOR, raptor, Beclin-1, p62 and LC3-II. RT-PCR technique was employed to assess genes involved in hypertrophy and lipid metabolism. Our data revealed increased LV thickness and LV chamber size as well as decreased fractional shortening following high fat diet intake, the effect was nullified by PTP1B knockout. High fat diet intake compromised cardiomyocyte contractile function as evidenced by decreased peak shortening, maximal velocity of shortening/relengthening, intracellular Ca²⁺ release as well as prolonged duration of relengthening and intracellular Ca²⁺ decay, the effects of which were alleviated by PTP1B knockout. High fat diet resulted in enlarged cardiomyocyte area and increased lipid accumulation, which were attenuated by PTP1B knockout. High fat diet intake dampened myocardial autophagy as evidenced by decreased LC3-II conversion and Beclin-1, increased p62 levels as well as decreased phosphorylation of AMPK and raptor, the effects of which were significantly alleviated by PTP1B knockout. Pharmacological inhibition of AMPK using compound C disengaged PTP1B knockout-conferred protection against fatty acid-induced cardiomyocyte contractile anomalies. Taken together, our results suggest that PTP1B knockout offers cardioprotection against high fat diet intake through activation of AMPK. This article is part of a Special Issue entitled

Usefulness of 123I-BMIPP myocardial imaging in patients with stable effort angina and unstable angina

International Nuclear Information System (INIS)

Inoue, Seiji; Kobayashi, Hideki; Oka, Toshiaki; Kawaguchi, Masao; Momose, Mitsuru; Kasanuki, Hiroshi; Kusakabe, Kiyoko; Hosoda, Saichi

1995-01-01

We evaluated the clinical significance of myocardial imaging using 123 I-15-(p-iodophenyl)-3-methyl pentadecanoic acid (BMIPP) scintigraphy in patients with stable effort angina pectoris (SAP) and unstable angina pectoris (UAP). Thirty-three patients with SAP were studied using rest BMIPP and stress 201 TlCl (Tl) myocardial scintigraphy, and 13 patients with worsening effort type of UAP were also examined using both rest BMIPP and Tl scintigraphy. We compared those BMIPP findings with myocardial perfusion images obtained with Tl and the regional wall motion determined by left ventriculography. In 45% of 282 segments of myocardial ischemia of SAP, the degree of myocardial uptake of BMIPP was concordant with that of stress Tl and the defect score of Tl was higher than that of BMIPP. On the other hand, in 32% of 62 segments of ischemia of UAP, the degree of myocardial BMIPP and Tl uptake was concordant and BMIPP defect score was higher than Tl score. In SAP, the decrease in regional wall motion agreed better with the decrease in myocardial uptake of BMIPP than that of Tl. These results suggest that myocardial ischemic regions decreased BMIPP uptake show the disturbance of fatty acid metabolism and lead to abnormal wall motions. Such ischemic regions may be clinically severe state in patients with angina pectoris. (author)

Quantitative assessment of left ventricular systolic wall thickening using multidetector computed tomography

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Kristensen, Thomas S; Kofoed, Klaus F; Møller, Daniel V

2009-01-01

BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic echocard......BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic...... echocardiography (TTE). MATERIALS AND METHODS: Sixty-four patients with known or suspected coronary artery disease underwent ECG-gated 64-slice MDCT and TTE. Regional left ventricular contractile function was measured by percent systolic wall thickening (SWT) in 16 myocardial segments using MDCT, and compared...

Thick filament length and isoform composition determine self-organized contractile units in actomyosin bundles.

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Thoresen, Todd; Lenz, Martin; Gardel, Margaret L

2013-02-05

Diverse myosin II isoforms regulate contractility of actomyosin bundles in disparate physiological processes by variations in both motor mechanochemistry and the extent to which motors are clustered into thick filaments. Although the role of mechanochemistry is well appreciated, the extent to which thick filament length regulates actomyosin contractility is unknown. Here, we study the contractility of minimal actomyosin bundles formed in vitro by mixtures of F-actin and thick filaments of nonmuscle, smooth, and skeletal muscle myosin isoforms with varied length. Diverse myosin II isoforms guide the self-organization of distinct contractile units within in vitro bundles with shortening rates similar to those of in vivo myofibrils and stress fibers. The tendency to form contractile units increases with the thick filament length, resulting in a bundle shortening rate proportional to the length of constituent myosin thick filament. We develop a model that describes our data, providing a framework in which to understand how diverse myosin II isoforms regulate the contractile behaviors of disordered actomyosin bundles found in muscle and nonmuscle cells. These experiments provide insight into physiological processes that use dynamic regulation of thick filament length, such as smooth muscle contraction. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Chronic myocardial infarction detection and characterization during coronary artery calcium scoring acquisitions.

LENUS (Irish Health Repository)

Rodríguez-Granillo, Gastón A

2012-01-05

Hypoenhanced regions on multidetector CT (MDCT) coronary angiography correlate with myocardial hyperperfusion. In addition to a limited capillary density, chronic myocardial infarction (MI) commonly contains a considerable amount of adipose tissue.

Patency of the infarct-related coronary artery--a pertinent factor in late recovery of myocardial fatty acid metabolism among patients receiving thrombolytic therapy?

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Walamies, M; Virtanen, V; Koskinen, M; Uusitalo, A

1994-09-01

The decrease in mortality among patients receiving thrombolytic therapy for myocardial infarction is greater than would be expected from the improvement in left ventricular contractile function alone; thus some additional advantage of recanalization of the infarct-related coronary artery probably exists. Changes in the post-infarction myocardial metabolic state with respect to artery patency have not been studied with a gamma camera previously. A single-photon emission tomography scan using the fatty acid analogue para-123I-iodophenylpentadecanoic acid was performed at rest before hospital discharge on nine patients with first anterior myocardial infarction. All patients had received intravenous thrombolytic therapy at the beginning of the insult. The semiquantitative analysis of the left ventricle included a total of 44 segments in each patient. The test was repeated 3 months later, with the patients divided into two groups: six patients had an angiographically patent left anterior descending coronary artery (group A), and three an occluded artery (group B). In group A the number of myocardial segments with abnormal (acid uptake was initially 20.2 +/- 4.7 (mean +/- SD) and was reduced to 11.3 +/- 6.1 during the follow-up (95% confidence interval of the decrease 16.0-1.7 segments). In group B the number of these aberrant segments was fairly constant (21.7 +/- 13.1, initial test, and 21.3 +/- 13.3, retest). Our preliminary results suggest that even when thrombolytic therapy fails to prevent myocardial infarction, myocardial fatty acid metabolism has a better change of recovering if the relevant coronary artery has regained its patency.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial perfusion SPECT imaging in patients with myocardial bridging

International Nuclear Information System (INIS)

Fang Wei; Qiu Hong; Yang Weixian; Wang Feng; He Zuoxiang

2008-01-01

Objective: Stress myocardial perfusion SPECT imaging was used to assess myocardial ischemia in patients with myocardial bridging. Methods: Ninety-six patients with myocardial bridging of the left anterior descending artery documented by coronary angiography were included in this study. All under- went exercise or pharmacological stress myocardial perfusion SPECT assessing myocardial ischemia. None had prior myocardial infarction. One year follow-up by telephone interview was performed in all patients. Results The mean stenotic severity of systolic phase on angiography was (65 ± 19)%. In the SPECT study, 20 of 96 (20.8%) patients showed abnormal perfusion. This percentage was significantly higher than that of stress electrocardiogram (ECG). The higher positive rate of SPECT perfusion images was showed in the group of patients with severe systolic narrowing (≥75%) than that with mild-to-moderate systolic narrowing (50% vs 6.3%, P<0.001). The prevalence of abnormal image was significantly higher in ELDERLY PEOPLE; patients with STT change on rest ECG than in those with normal rest ECG (54.2% vs 9.7%, P<0.001). During follow-up, one patient with abnormal SPECT perfusion image sustained angina and accepted percutaneous coronary intervention, and no cardiac event occurred in patients with normal images. Conclusions: Stress myocardial perfusion SPECT imaging can be used effectively for assessing myocardial ischemia and has potential prognostic value for patients with myocardial bridging. (authors)

Correlation between Left Ventricular Global and Regional Longitudinal Systolic Strain and Impaired Microcirculation in Patients with Acute Myocardial Infarction

DEFF Research Database (Denmark)

Løgstrup, Brian B; Høfsten, Dan Eik; Christophersen, Thomas Brøcher

2012-01-01

investigated if LRS and GLS imaging is superior to conventional measures of left ventricle (LV) function. Methods: In a consecutive population of first time AMI patients, who underwent successful revascularization, we performed comprehensive TTE. GLS and LRS were obtained from the three standard apical views...... elevation myocardial infarction. The GLS was -15.2 [-19.3;-10.1]% in the total population of 183 patients. Total wall motion score index (WMSI) in the population was 1.19 [1;1.5]. Eighty-five patients suffered from culprit lesion in left anterior descending artery (LAD). The CFR in these patients was 1......Objectives: We investigated the correlation between left ventricular global and regional longitudinal systolic strain (GLS and LRS) and coronary flow reserve (CFR) assessed by transthoracic echocardiography (TTE) in patients with a recent acute myocardial infarction (AMI). Furthermore, we...

delta-Opioid-induced pharmacologic myocardial hibernation during cardiopulmonary resuscitation.

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Fang, Xiangshao; Tang, Wanchun; Sun, Shijie; Weil, Max Harry

2006-12-01

Cardiac arrest and cardiopulmonary resuscitation is an event of global myocardial ischemia and reperfusion, which is associated with severe postresuscitation myocardial dysfunction and fatal outcome. Evidence has demonstrated that mammalian hibernation is triggered by cyclic variation of a delta-opiate-like compound in endogenous serum, during which the myocardial metabolism is dramatically reduced and the myocardium tolerates the stress of ischemia and reperfusion without overt ischemic and reperfusion injury. Previous investigations also proved that the delta-opioid agonist elicited the cardioprotection in a model of regional ischemic intact heart or myocyte. Accordingly, we were prompted to search for an alternative intervention of pharmacologically induced myocardial hibernation that would result in rapid reductions of myocardial metabolism and therefore minimize the myocardial ischemic and reperfusion injury during cardiac arrest and cardiopulmonary resuscitation. Prospective, controlled laboratory study. University-affiliated research laboratory. In the series of studies performed in the established rat and pig model of cardiac arrest and cardiopulmonary resuscitation, the delta-opioid receptor agonist, pentazocine, was administered during ventricular fibrillation. : The myocardial metabolism reflected by the concentration of lactate, or myocardial tissue PCO2 and PO2, is dramatically reduced during cardiac arrest and cardiopulmonary resuscitation. These are associated with less severe postresuscitation myocardial dysfunction and longer duration of postresuscitation survival. delta-Opioid-induced pharmacologic myocardial hibernation is an option to minimize the myocardial ischemia and reperfusion injury during cardiac arrest and cardiopulmonary resuscitation.

Histochemical and immunohistochemical analyses of the myocardial scar fallowing acute myocardial infarction

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Tatić Vujadin

2012-01-01

Full Text Available Background/Aim. The heart has traditionally been considered as a static organ without capacity of regeneration after trauma. Currently, the more and more often asked question is whether the heart has any intrinsic capacities to regenerate myocytes after myocardial infarction. The aim of this study was to present the existence of the preserved muscle fibers in the myocardial scar following myocardial infarction as well as the presence of numerous cells of various size and form that differently reacted to the used immunohistochemical antibodies. Methods. Histological, histochemical and immunohistochemical analyses of myocardial sections taken from 177 patients who had died of acute myocardial infarction and had the myocardial scar following myocardial infarction, were carried out. More sections taken both from the site of acute infarction and scar were examined by the following methods: hematoxylin-eosin (HE, periodic acid schiff (PAS, PAS-diastasis, Masson trichrom, Malory, van Gieson, vimentin, desmin, myosin, myoglobin, alpha actin, smoth muscle actin (SMA, p53, leukocyte common antigen (LCA, proliferating cell nuclear antigen (PCNA, Ki-67, actin HHF35, CD34, CD31, CD45, CD45Ro, CD8, CD20. Results. In all sections taken from the scar region, larger or smaller islets of the preserved muscle fibers with the signs of hypertrophy were found. In the scar, a large number of cells of various size and form: spindle, oval, elongated with abundant cytoplasm, small with one nucleus and cells with scanty cytoplasm, were found. The present cells differently reacted to histochemical and immunohistochemical methods. Large oval cells showed negative reaction to lymphocytic and leukocytic markers, and positive to alpha actin, actin HHF35, Ki-67, myosin, myoglobin and desmin. Elongated cells were also positive to those markers. Small mononuclear cells showed positive reaction to lymphocytic markers. Endothelial and smooth muscle cells in the blood vessel walls

Clinical Relationship between Steatocholecystitis and Gallbladder Contractility Measured by Cholescintigraphy

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Chang Seok Bang

2015-01-01

Full Text Available Objective. Contractility of gallbladder is known to be decreased in fatty gallbladder diseases. However, clinical estimation data about this relationship is still lacking. The aim of this study was to investigate the association between steatocholecystitis and contractility of gallbladder. Methods. Patients with cholecystitis (steatocholecystitis versus nonsteatocholecystitis who underwent cholescintigraphy before cholecystectomy were retrospectively evaluated in a single teaching hospital of Korea. The association of steatocholecystitis with contractility of gallbladder, measured by preoperative cholescintigraphy, was assessed by univariable and multivariable analysis. Results. A total of 432 patients were finally enrolled (steatocholecystitis versus nonsteatocholecystitis; 75 versus 357, calculous versus acalculous cholecystitis; 316 versus 116. In the multivariable analysis, age (OR: 0.94, 95% CI: 0.90–0.99, P=0.01 and total serum cholesterol (OR: 1.02, 95% CI: 1.01–1.04, P=0.04 were related to steatocholecystitis in patients with acalculous cholecystitis. Only age (OR: 0.97, 95% CI: 0.94–0.99, P=0.004 was significantly related to steatocholecystitis in patients with calculous cholecystitis. However, ejection fraction of gallbladder reflecting contractility measured by cholescintigraphy was not related to steatocholecystitis irrespective of presence of gallbladder stone in patients with cholecystitis. Conclusion. Ejection fraction of gallbladder measured by cholescintigraphy cannot be used for the detection or confirmation of steatocholecystitis.

Evaluation of left ventricular myocardial function in patients with coronary artery disease and myocardial dysfunction before and after coronary artery bypass grafting by cine magnetic resonance imaging

International Nuclear Information System (INIS)

Juergens, K.U.; Renger, B.; Reimer, P.; Tombach, B.; Heindel, W.; Wichter, T.; Bruns, H.J.; Vahlhaus, C.; Janssen, F.W.; Breithardt, G.

2001-01-01

Purpose: To evaluate left ventricular (LV) myocardial function in ten patients with coronary artery disease (CAD) preoperatively and 6 months after coronary bypass grafting (CABG) by cardiac MRI. Material and methods: Ten patients (mean 65.2±5.9 years) with angiographically proven CAD and an indication for elective CABG underwent prospective evaluation of global LV function and regional wall motion by Cine-MRI at rest using a multiphase FLASH-2D sequence following regions of interest (ROI)-defined diagnostics of regional myocardial wall motion by means of levocardiography. Within the ROIs a total of 613 LV myocardial segments were analyzed preceding and following surgical revascularization. Results were compared with the data of 10 healthy volunteers. Results: Preoperatively, patients showed reduced stroke volume and ejection fraction compared with volunteers (p [de

An incidental finding of myocardial uptake on HDP bone scan

International Nuclear Information System (INIS)

Smith, T.

1998-01-01

Full text: A 75 year old male referred with a history of wrist pain for a HDP bone scan(700Mbq) had dynamic and blood pool images. A posterior sweep and planar images were performed after 2 hours. The scan demonstrated a fracture of the left radial styloid, other degenerative arthritis and diffuse tracer uptake throughout the myocardium. The differential diagnoses included cardiac amyloid, myocardial infarction (MI) and calcific pericarditis. The patient, a non insulin dependent diabetic with previous MI in 1978 and hypertension had nocturnal dyspnoea and no chest pain. Chest X-ray was normal. ECG revealed old inferior infarct. Echocardiography showed mild hypokinesis of the inferior wall, low normal LV contractility, normal pericardium and no evidence of amyloid. A Rest (400Mbq) / Stress(1200Mbq) Sestamibi(MIBI) was performed to assess status of ischaemic heart disease (IHD). The patient experienced leg fatigue and shortness of breath but no chest pain. Rest ECG showed sinus bradycardia with ST/T wave changes. Stress ECG showed ST segment depression (0.5mm). Planar and SPECT studies showed reversible perfusion defects in the anterior wall and apex with a fixed inferolateral defect. Gated SPECT showed normal wall motion apart from the inferolateral infarct. The exact cause of the HDP uptake in the myocardium is unknown. The echo findings exclude amyloid or pericarditis. The MIBI study confirmed a small inferolateral infarct and myocardial ischaemia in the anterior wall and apex. The scan has affected patient management by diagnosing a fracture of the radial styloid and confirming previous infarction and myocardial ischaemia. An open view must be taken of the cardiac HDP uptake. The most likely diagnosis in this patient is silent IHD, which has been demonstrated in one other case known to us

The role of voltage-gated potassium channels in the regulation of mouse uterine contractility

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Abel Peter W

2007-11-01

Full Text Available Abstract Background Uterine smooth muscle cells exhibit ionic currents that appear to be important in the control of uterine contractility, but how these currents might produce the changes in contractile activity seen in pregnant myometrium has not been established. There are conflicting reports concerning the role of voltage-gated potassium (Kv channels and large-conductance, calcium-activated potassium (BK channels in the regulation of uterine contractility. In this study we provide molecular and functional evidence for a role for Kv channels in the regulation of spontaneous contractile activity in mouse myometrium, and also demonstrate a change in Kv channel regulation of contractility in pregnant mouse myometrium. Methods Functional assays which evaluated the effects of channel blockers and various contractile agonists were accomplished by quantifying contractility of isolated uterine smooth muscle obtained from nonpregnant mice as well as mice at various stages of pregnancy. Expression of Kv channel proteins in isolated uterine smooth muscle was evaluated by Western blots. Results The Kv channel blocker 4-aminopyridine (4-AP caused contractions in nonpregnant mouse myometrium (EC50 = 54 micromolar, maximal effect at 300 micromolar but this effect disappeared in pregnant mice; similarly, the Kv4.2/Kv4.3 blocker phrixotoxin-2 caused contractions in nonpregnant, but not pregnant, myometrium. Contractile responses to 4-AP were not dependent upon nerves, as neither tetrodotoxin nor storage of tissues at room temperature significantly altered these responses, nor were responses dependent upon the presence of the endometrium. Spontaneous contractions and contractions in response to 4-AP did not appear to be mediated by BK, as the BK channel-selective blockers iberiotoxin, verruculogen, or tetraethylammonium failed to affect either spontaneous contractions or 4-AP-elicited responses. A number of different Kv channel alpha subunit proteins were

Quantitative evaluation of myocardial perfusion and heart function using a non-invasive double isotope technique

Energy Technology Data Exchange (ETDEWEB)

Knapp, W H; Doll, J; Georgi, P [Deutsches Krebsforschungszentrum, Heidelberg (Germany, F.R.). Inst. fuer Nuklearmedizin; Tillmanns, H [Heidelberg Univ. (Germany, F.R.). Innere Medizin 3

1976-11-01

This paper describes a non-invasive double nuclide technique for the simultaneous measurement of minimal cardiac transit times (MTT) and regional 'myocardial appearance times' (MAT) using gamma camera and computer. MAT is defined as the time lag between the appearance of an indicator with myocardial affinity in the aortic root and its extraction in the myocardial cells. The extraction can be identified as an increase of the ratio between the count rates of the two nuclides e.g. /sup 201/Tl-chloride and sup(113m)In DTPA. The clinical evaluation of this method allows the following conclusions: 1) MAT, determined over several circumscript myocardial regions permits the qualitative diagnosis of a coronary artery disease with high confidence. 2) Indices of nutritive myocardial blood flow (INF), derived by MAT using several representative areas of myocardium, show a definite correlation to the degree of coronary artery disease. In addition to the localization of infarction and the determination of infarct size, the technique described promises a quantitative evaluation of the regional myocardial perfusion. Simultaneously measured MTT help to assess segmental cardiac performance.

Tomoscintigraphic assessment of myocardial metabolic heterogenity

International Nuclear Information System (INIS)

Roesler, H.; Hess, T.; Weiss, M.; Noelpp, U.; Mueller, G.; Hoeflin, F.; Kinser, J.

1983-01-01

I-123-omega-heptadecanoic acid (HDA) was evaluated for myocardial scanning in 59 healthy volunteers and 133 patients, using a 7-pinhole collimator. Early (uptake) and late (retention) images were compared visually. Regional HDA elimination was also followed semiquantitatively based on the calculation of a retention-over-uptake ratio, R(phi), derived from the maximal counts/pixel in 60 midventricular slice sectors. The healthy heart concentrated HDA homogeneously in all segments with no difference between early and late images. The minimal R(phi), taken as representative of that myocardium with the best function, was unchanged after maximal ergometer stress and with dipyramidole-induced hyperperfusion. A circumscribed decreased HDA uptake is the clear-cut criterion for an abnormal finding. HDA tomography of the myocardium had an 86% sensitivity for myocardial infarcts (MIs) up to 4 wk old, and 83% for myocardial scars (MSs). Comparing early and late tomograms, we find a cool-warm sequence more often with acute and subacute MIs. A cool-cool or a cold-cold sequence dominated with MSs. HDA tomoscintigraphy cannot replace TI-201 for the evaluation of regional coronary reserve in coronary heart disease

Simultaneous cardiac output and regional myocardial perfusion determination with PET and nitrogen 13 ammonia

DEFF Research Database (Denmark)

Hove, Jens D; Kofoed, Klaus F; Wu, Hsiao M

2003-01-01

The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia.......The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia....

Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion

Energy Technology Data Exchange (ETDEWEB)

Caldwell, J.H.; Martin, G.V.; Link, J.M.; Krohn, K.A.; Bassingthwaighte, J.B. (Seattle VA Medical Center, WA (USA))

1990-01-01

Imaging {sup 123}I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, {sup 131}I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 {plus minus} 0.43) was similar to that for microspheres (0.94 {plus minus} 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion

International Nuclear Information System (INIS)

Caldwell, J.H.; Martin, G.V.; Link, J.M.; Krohn, K.A.; Bassingthwaighte, J.B.

1990-01-01

Imaging 123 I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131 I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 ± 0.43) was similar to that for microspheres (0.94 ± 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal

Iodophenylpentadecanoic acid-myocardial blood flow relationship during maximal exercise with coronary occlusion.

Science.gov (United States)

Caldwell, J H; Martin, G V; Link, J M; Krohn, K A; Bassingthwaighte, J B

1990-01-01

Imaging 123I-labeled iodophenylpentadecanoic acid (IPPA) uptake and clearance from the myocardium following exercise has been advocated as a means of detecting myocardial ischemia because fatty acid deposition is enhanced and clearance prolonged in regions of low flow. However, normal regional myocardial blood flows are markedly heterogeneous, and it is not known how this heterogeneity affects regional metabolism or substrate uptake and thus image interpretation. In five instrumented dogs running at near maximal workload on a treadmill, 131I-labeled IPPA and 15-micron 46Sc microspheres were injected into the left atrium after 30 sec of circumflex coronary artery occlusion. Microsphere and IPPA activity were determined in 250 mapped pieces of myocardium of approximately 400 mg. Myocardial blood flows (from microspheres) ranged from 0.05 to 7.6 ml/min/g. Deposition of IPPA was proportional to regional flows (r = 0.83) with an average retention of 25%. The mean endocardial-epicardial ratio for IPPA (0.90 +/- 0.43) was similar to that for microspheres (0.94 +/- 0.47; p = 0.08). Thus, initial IPPA deposition during treadmill exercise increases in proportion to regional myocardial blood flow over a range of flows from very low to five times normal.

Effect of heat stress on contractility of tissue-engineered artificial skeletal muscle.

Science.gov (United States)

Takagi, Shunya; Nakamura, Tomohiro; Fujisato, Toshia

2018-01-23

The effects of heat stress on tissue like skeletal muscle have been widely studied. However, the mechanism responsible for the effect of heat stress is still unclear. A useful experimental tissue model is necessary because muscle function in cell culture may differ from native muscle and measuring its contractility is difficult. We previously reported three-dimensional tissue-engineered artificial skeletal muscle (TEM) that can be easily set in a measurement apparatus for quantitative evaluation of contractility. We have now applied TEM to the investigation of heat stress. We analyzed contractility immediately after thermal exposure at 39 °C for 24 or 48 h to evaluate the acute effects and after thermal exposure followed by normal culture to evaluate the aftereffects. Peak twitch contractile force and time-to-peak twitch were used as contractile parameters. Heat stress increased the TCF in the early stage (1 week) after normal culture; the TCF decreased temporarily in the middle to late stages (2-3 weeks). These results suggest that heat stress may affect both myoblast fusion and myotube differentiation in the early stage of TEM culture, but not myotube maturation in the late stage. The TCF increase rate with thermal exposure was significantly higher than that without thermal exposure. Although detailed analysis at the molecular level is necessary for further investigation, our artificial skeletal muscle may be a promising tool for heat stress investigation.

Effects of ageing on single muscle fibre contractile function following short-term immobilisation

DEFF Research Database (Denmark)

Hvid, Lars G; Ørtenblad, Niels; Aagaard, Per

2011-01-01

Very little attention has been given to the combined effect of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...

Comparative assessment of 18F-fluorodeoxyglucose PET and 99mTc-tetrofosmin SPECT for the prediction of functional recovery in patients with reperfused acute myocardial infarction

International Nuclear Information System (INIS)

Shirasaki, Haruhisa; Nakano, Akira; Uzui, Hiroyasu; Ueda, Takanori; Lee, Jong-Dae; Yonekura, Yoshiharu; Okazawa, Hidehiko

2006-01-01

Purpose: Although preserved glucose metabolism is considered to be a marker of myocardial viability in the chronic stage, it has not been fully elucidated whether this is also true with regard to reperfused acute myocardial infarction (AMI). The aim of this study was to compare the diagnostic performance of 99m Tc-tetrofosmin SPECT and 18 F-fluorodeoxyglucose (FDG) PET for the prediction of functional recovery in reperfused AMI.Methods: The study population comprised 28 patients. Both tetrofosmin SPECT and FDG PET were performed in all 28 patients at ca. 2 weeks and in 23 at 6 months. The tetrofosmin and FDG findings in infarct-related segments were compared with the regional wall motion score assessed by left ventriculography over 6 months to determine the predictive value for functional recovery. Of 120 infarct-related segments, 83 had preserved flow (tetrofosmin uptake ≥50%) and 81 had preserved glucose metabolism (FDG uptake ≥40%). The sensitivity and specificity of tetrofosmin SPECT for the prediction of functional recovery tended to be superior to those of FDG PET (90.0% and 72.5% vs 85.0% and 67.5%, respectively). Thirteen segments with preserved flow and decreased glucose metabolism demonstrated marked recovery of contractile function from 2.5±1.0 to 1.4±1.4 (p<0.01), with restoration of glucose metabolism at 6 months. In contrast, 11 segments with decreased flow and preserved glucose metabolism demonstrated incomplete functional improvement from 3.0±0.8 to 2.2±1.2. In the subacute phase, preserved myocardial blood flow is more reliable than glucose metabolism in predicting functional recovery in reperfused myocardium. (orig.)

Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction

Energy Technology Data Exchange (ETDEWEB)

Fujino, Takayuki; Ishii, Yoshinao; Hirasawa, Kunihiko; Tateda, Kunihiko [Asahikawa City Hospital, Hokkaido (Japan); Takeuchi, Toshiharu; Kikuchi, Kenjiro; Hasebe, Naoyuki [Asahikawa Medical Coll., Hokkaido (Japan)

2003-09-01

The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-{beta}-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The IR, estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion. (author)

Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction

International Nuclear Information System (INIS)

Fujino, Takayuki; Ishii, Yoshinao; Hirasawa, Kunihiko; Tateda, Kunihiko; Takeuchi, Toshiharu; Kikuchi, Kenjiro; Hasebe, Naoyuki

2003-01-01

The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-β-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The IR, estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion. (author)

Recovery of BMIPP uptake and regional wall motion in insulin resistant patients following angioplasty for acute myocardial infarction.

Science.gov (United States)

Fujino, Takayuki; Ishii, Yoshinao; Takeuchi, Toshiharu; Hirasawa, Kunihiko; Tateda, Kunihiko; Kikuchi, Kenjiro; Hasebe, Naoyuki

2003-09-01

The effect of insulin resistance (IR) on the fatty acid metabolism of myocardium, and therefore on the recovery of left ventricular (LV) wall motion, has not been established in patients with acute myocardial infarction (AMI). A total of consecutive 58 non-diabetic AMI patients who had successfully undergone emergency coronary angioplasty were analyzed retrospectively. They were categorized into 2 groups, normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), based on a 75-g oral glucose tolerance test (OGTT). The parameters of OGTT, myocardial scintigraphy (n=58) (thallium-201 (Tl) and iodine-123-beta-methyl-iodophenylpentadecanoic acid (BMIPP)) and left ventriculography (n=24) were compared in the 2 groups after reperfusion (acute phase) and 3-4 weeks after the AMI (chronic phase). The insulin resistance (IR), estimated by the serum concentration of insulin at 120 min (IRI 120') of the OGTT and by the HOMA (the homeostasis model assessment) index, was higher in the IGT group than in NGT group. An inverse correlation was found between the recovery of regional LV wall motion in the ischemic lesion and the IRI 120' and HOMA index. Although the recovery of BMIPP uptake from the acute to the chronic phase was higher in the IGT group, it was only correlated with the degree of IRI 120', not with the HOMA. IR accompanied by IGT can negatively influence the recovery of regional LV wall motion.

Progesterone Metabolites Produced by Cytochrome P450 3A Modulate Uterine Contractility in a Murine Model

Science.gov (United States)

Patil, Avinash S.; Swamy, Geeta K.; Murtha, Amy P.; Heine, R. Phillips; Zheng, Xiaomei; Grotegut, Chad A.

2015-01-01

Objective: We seek to characterize the effect of progesterone metabolites on spontaneous and oxytocin-induced uterine contractility. Study Design: Spontaneous contractility was studied in mouse uterine horns after treatment with progesterone, 2α-hydroxyprogesterone, 6β-hydroxyprogesterone (6β-OHP), 16α-hydroxyprogesterone (16α-OHP), or 17-hydroxyprogesterone caproate (17-OHPC) at 10−9 to 10−6 mol/L. Uterine horns were exposed to progestins (10−6 mol/L), followed by increasing concentrations of oxytocin (1-100 nmol/L) to study oxytocin-induced contractility. Contraction parameters were compared for each progestin and matched vehicle control using repeated measures 2-way analysis of variance. In vitro metabolism of progesterone by recombinant cytochrome P450 3A (CYP3A) microsomes (3A5, 3A5, and 3A7) identified major metabolites. Results: Oxytocin-induced contractile frequency was decreased by 16α-OHP (P = .03) and increased by 6β-OHP (P = .05). Progesterone and 17-OHPC decreased oxytocin-induced contractile force (P = .02 and P = .04, respectively) and frequency (P = .02 and P = .03, respectively). Only progesterone decreased spontaneous contractile force (P = .02). Production of 16α-OHP and 6β-OHP metabolites were confirmed in all CYP3A isoforms tested. Conclusion: Progesterone metabolites produced by maternal or fetal CYP3A enzymes influence uterine contractility. PMID:26037300

Electro-mechanical characteristics of myocardial infarction border zones and ventricular arrhythmic risk: novel insights from grid-tagged cardiac magnetic resonance imaging

International Nuclear Information System (INIS)

Wong, Dennis T.L.; Weightman, Michael J.; Baumert, Mathias; Tayeb, Hussam; Richardson, James D.; Puri, Rishi; Bertaso, Angela G.; Roberts-Thomson, Kurt C.; Sanders, Prashanthan; Worthley, Matthew I.; Worthley, Stephen G.

2012-01-01

To investigate whether grid-tag myocardial strain evaluation can characterise 'border-zone' peri-infarct region and identify patients at risk of ventricular arrhythmia as the peri-infarct myocardial zone may represent an important contributor to ventricular arrhythmia following ST-segment elevation myocardial infarction (STEMI). Forty-five patients with STEMI underwent cardiac magnetic resonance (CMR) imaging on days 3 and 90 following primary percutaneous coronary intervention (PCI). Circumferential peak circumferential systolic strain (CS) and strain rate (CSR) were calculated from grid-tagged images. Myocardial segments were classified into 'infarct', 'border-zone', 'adjacent' and 'remote' regions by late-gadolinium enhancement distribution. The relationship between CS and CSR and these distinct myocardial regions was assessed. Ambulatory Holter monitoring was performed 14 days post myocardial infarction (MI) to estimate ventricular arrhythmia risk via evaluation of heart-rate variability (HRV). We analysed 1,222 myocardial segments. Remote and adjacent regions had near-normal parameters of CS and CSR. Border-zone regions had intermediate CS (-9.0 ± 4.6 vs -5.9 ± 7.4, P < 0.001) and CSR (-86.4 ± 33.3 vs -73.5 ± 51.4, P < 0.001) severity compared with infarct regions. Patients with 'border-zone' peri-infarct regions had reduced very-low-frequency power on HRV analysis, which is a surrogate for ventricular arrhythmia risk (P = 0.03). Grid-tagged CMR-derived myocardial strain accurately characterises the mechanical characteristics of 'border-zone' peri-infarct region. Presence of 'border-zone' peri-infarct region correlated with a surrogate marker of heightened arrhythmia risk following STEMI. (orig.)

Evaluation of nonradioactive, colored microspheres for measurement of regional myocardial blood flow in dogs

International Nuclear Information System (INIS)

Hale, S.L.; Alker, K.J.; Kloner, R.A.

1988-01-01

Measurement of regional myocardial blood flow (RMBF) is crucial in experimental studies of myocardial ischemia and reperfusion in dogs. The standard measurement technique uses radioactive microspheres; however, not all institutions are able to dispose of radioactive waste and therefore cannot make use of this method. We tested a new, nonradioactive microsphere, labeled with colors instead of nuclides. Simultaneous blood flow measurements with two nuclide-labeled and two colored microspheres were performed after coronary occlusion in dogs. Both techniques show a within-method correlation of r greater than 0.98. Duplicate variability for paired RMBF values in 80 samples was 8.7 +/- 0.1% when computed with radioactive microspheres and 13.2 +/- 1.8% when computed with colored microspheres. There was a good correlation in the measurement of RMBF between the radioactive- and colored-microsphere methods (r = 0.98). The best-fitting linear regression line was expressed by the formula: Colored-microsphere RMBF = 1.11 (radioactive-microsphere RMBF)-0.02. When measured by colored microspheres, RMBF was approximately 8% higher than when computed with radioactive microspheres for blood flow values of 0-2 ml/min/g. When blood flow was increased pharmacologically to levels of 2-7.5 ml/min/g, colored microspheres yielded blood flow values 39% higher than the values computed by radioactive microspheres. We conclude that the nonradioactive, colored-microsphere method correlates with the radioactive technique, but at high flows, it yields values greater than those obtained with radioactive microspheres

Tumor necrosis factor-alpha increases myocardial microvascular transport in vivo

DEFF Research Database (Denmark)

Hansen, P R; Svendsen, Jesper Hastrup; Høyer, S

1994-01-01

Tumor necrosis factor-alpha (TNF-alpha) is a primary mediator in the pathogenesis of tissue injury, and high circulating levels of TNF-alpha are found in a variety of pathological conditions. In open-chest anesthetized dogs, the effects of intracoronary recombinant human TNF-alpha (rTNF-alpha; 100...... in cardiac output and was associated with the appearance of areas with myocardial necrosis in the regional left ventricular wall. The myocardial plasma flow rate and maximum plasma flow rate in response to a 30-s coronary occlusion were not influenced by rTNF-alpha, although a decrease in the myocardial...... ng/kg for 60 min) on myocardial microvascular transport of a small hydrophilic indicator was examined by the single-injection, residue-detection method. Intracoronary infusion of rTNF-alpha increased myocardial microvascular transport after 120 min. This increase was preceded by a sustained decline...

Alignment of human cardiomyocytes on laser patterned biphasic core/shell nanowire assemblies

International Nuclear Information System (INIS)

Kiefer, Karin; Haidar, Ayman; Abdul-Khaliq, Hashim; Lee, Juseok; Martinez Miró, Marina; Kaan Akkan, Cagri; Cenk Aktas, Oral; Veith, Michael

2014-01-01

The management of end stage heart failure patients is only possible by heart transplantation or by the implantation of artificial hearts as a bridge for later transplantation. However, these therapeutic strategies are limited by a lack of donor hearts and by the associated complications, such as coagulation and infection, due to the used artificial mechanical circulatory assist devices. Therefore, new strategies for myocardial regenerative approaches are under extensive research to produce contractile myocardial tissue in the future to replace non-contractile myocardial ischemic and scarred tissue. Different approaches, such as cell transplantation, have been studied intensively. Although successful approaches have been observed, there are still limitations to the application. It is envisaged that myocardial tissue engineering can be used to help replace infarcted non-contractile tissue. The developed tissue should later mimic the aligned fibrillar structure of the extracellular matrix and provide important guidance cues for the survival, function and the needed orientation of cardiomyocytes. Nanostructured surfaces have been tested to provide a guided direction that cells can follow. In the present study, the cellular adhesion/alignment of human cardiomyocytes and the biocompatibility have been investigated after cultivation on different laser-patterned nanowires compared with unmodified nanowires. As a result, the nanostructured surfaces possessed good biocompatibility before and after laser modification. The laser-induced scalability of the pattern enabled the growth and orientation of the adhered myocardial tissue. Such approaches may be used to modify the surface of potential scaffolds to develop myocardial contractile tissue in the future. (paper)

Imaging of cocaine-induced global and regional myocardial ischemia

International Nuclear Information System (INIS)

Oster, Z.H.; Som, P.; Wang, G.J.; Weber, D.A.

1991-01-01

Severe and often fatal cardiac complications have been reported in cocaine users with narrowed coronary arteries caused by atherosclerosis as well as in young adults with normal coronaries. The authors have found that in normal dogs cocaine induces severe temporary hypoperfusion of the left ventricle as indicated by a significantly lower 201Tl concentration compared to the baseline state. The most significant decrease in uptake occurred 5 min after injection and was more pronounced in the septal and apical segments. Following intravenous administration of cocaine, instead of gradual disappearance of 201Tl from the left ventricle, there was continuous increase in 201Tl concentration in the left ventricle. These imaging experiments indicate that the deleterious effects of cocaine on the heart are probably due to spasm of the coronaries and decreased myocardial perfusion. Since spasm of the large subpericardial vessels does not seem to explain the magnitude of the increased coronary resistance and decreased coronary flow after cocaine as described in the literature, it is suggested that microvascular spasm of smaller vessels plays a major role in the temporary decrease in perfusion. The data may also suggest that severe temporary myocardial ischemia is probably the initiating factor for the cardiac complications induced by cocaine

[Gallbladder contractility in children with functional abdominal pain or irritable bowel syndrome].

Science.gov (United States)

Iwańczak, Franciszek; Siedlecka-Dawidko, Jolanta; Iwanczak, Barbara

2013-07-01

III Rome Criteria of functional gastrointestinal disorders in children, distinguished the disturbances with abdominal pain, to which irritable bowel syndrome, functional abdominal pains, functional dyspepsia and abdominal migraine were included. THE AIM OF THE STUDY was sonographic assessment of the gallbladder and its contractility in functional abdominal pain and irritable bowel syndrome in children. The study comprised 96 children aged 6 to 18 years, 59 girls and 37 boys. Depending on diagnosis, the children were divided into three groups. 38 children with functional abdominal pain constituted the first group, 26 children with irritable bowel syndrome were included to the second group, the third group consisted of 32 healthy children (control group). Diagnosis of functional abdominal pain and irritable bowel syndrome was made based on the III Rome Criteria. In irritable bowel syndrome both forms with diarrhea (13) and with constipation (13) were observed. Anatomy and contractility of the gallbladder were assessed by ultrasound examination. The presence of septum, wall thickness, thick bile, vesicle volume in fasting state and 30th and 60th minute after test meal were taken into consideration. Test meal comprised about 15% of caloric requirement of moderate metabolism. Children with bile stones and organic diseases were excluded from the study. Thickened vesicle wall and thick bile were present more frequently in children with irritable bowel syndrome and functional abdominal pain than in control group (p functional abdominal pain than in irritable bowel syndrome and control group (p = 0.003, p = 0.05). Vesicle contractility after test meal was greatest in children with functional abdominal pain. Evaluation of diminished (smaller than 30%) and enlarged (greater then 80%) gallbladder contractility at 30th and 60th minute after test meal demonstrated disturbances of contractility in children with irritable bowel syndrome and functional abdominal pain. In children

Heart resistance to oxidative stress in rats of different genetic strains.

Science.gov (United States)

Belkina, L M; Lakomkin, V L; Zhukova, A G; Kirillina, T N; Saltykova, V A; Sazontova, T G; Kapel'ko, V I

2004-09-01

In August rats reperfusion after regional myocardial ischemia in situ or intracoronary administration of hydrogen peroxide less significantly suppressed contractile activity of the heart compared to Wistar rats. Activities of catalase and superoxide dismutase in the myocardium during reperfusion remained unchanged in August rats. In Wistar rats a profound inhibition of cardiac function was accompanied by a decrease in enzyme activity.

Myocardial perfusion and left ventricular function during exercise evaluated by 201Tl myocardial scintigraphy and 99mTc radionuclide ventriculography in patients treated with PTCA

International Nuclear Information System (INIS)

Honda, Toshio; Jo, Tadafumi; Doiuchi, Junji

1992-01-01

To evaluate the effects of percutaneous transluminal coronary angioplasty (PTCA), we investigated myocardial ischemia and left ventricular function during exercise before and after successful PTCA in 30 patients. We used extent and severity scores of 201 thallium ( 201 Tl) exercise myocardial scintigraphy to assess myocardial ischemia and determined global and regional left ventricular ejection fraction (EF and REF) of 99m Tc-RBC exercise radionuclide ventriculography to assess left ventricular function. The extent and severity scores of stress images were significantly less after PTCA than before PTCA. The scores of the redistribution images were unchanged before and after PTCA. Global EF during exercise was significantly higher after PTCA than before PTCA. There was no difference in resting global EF between before and after PTCA. Myocardial ischemia induced by exercise was semi-quantitatively analyzed as transient perfusion defect with severity score. Severity score was significantly less after PTCA than before PTCA. ΔEF, which was obtained by subtraction of resting global EF from exercise one, was significantly higher after PTCA than before PTCA. However, the degree of improvement in myocardial ischemia and left ventricular function varied from patient to patient. In 17 patients with one-vessel left anterior descending artery disease, ΔREF, which was determined by subtracting resting regional EF from exercise one, was significantly higher in septal and apical segments after PTCA than before PTCA. Myocardial ischemia and left ventricular function under exercise were alleviated by PTCA. However, the degree of improvement varied from patient to patient and it might have been affected by various factors including coronary dissection, edema, thrombus, restenosis, spasm, side branch stenosis or occlusion, distal thrombus, and myocardial hibernation. (author)

Prognostic value of Tc-99m tetrofosmin myocardial perfusion gated SPECT in patients with diabetes mellitus and suspected coronary artery disease

International Nuclear Information System (INIS)

Santos, Marcia Maria Sales dos; Pantoja, Mauricio da Rocha; Cwajg, Eduardo

2008-01-01

Background: The cardiovascular disease is the main cause of death among diabetic patients, which makes it crucial to identify the individuals at higher risk of cardiovascular events. Objective: To evaluate the prognostic value of scintigraphy with gated single photon emission computed tomography (SPECT) in patients with diabetes mellitus (DM) and suspected coronary artery disease. Methods: Retrospective study with 232 diabetic patients submitted to scintigraphy with gated SPECT. Perfusion Gated SPECT (scores and number of altered segments) as well as ventricular function parameters (ejection fraction, left ventricle volume and contractility) were evaluated. Cardiac death, acute ischemic coronary syndrome, revascularization procedures or encephalic vascular accident were considered future cardiovascular events. The uni- and multivariate analyses were carried out by the multiple logistic regression model (p< 0.05). Results: At the univariate analysis, age (p=0.02), chest angina (p=0.01), insulin therapy (p=0.02), myocardial perfusion abnormalities (p<0.0001), the number of segments involved (p=0.0001), the perfusion scores (p=0.0001), the ejection fraction (p=0.004), the final systolic volume (p=0.03) and the finding of segmental alteration at the LV contractility (p<0.0001) were associated with future events at the univariate analysis. At the multivariate analysis, the male sex (p=0.007), age (p=0.03), angina (p=0.001), insulin therapy (p=0.007) and the SDS ≥ 3 (p=0.0001), and the number of altered segments ≥ 3 (p=0.0001) were predictors of cardiovascular events. Conclusion: The myocardial scintigraphy with gated SPECT adds independent information to the stratification of the risk of future cardiovascular events in patients with DM and suspected coronary artery disease. (author)

Prognostic value of Tc-99m tetrofosmin myocardial perfusion gated SPECT in patients with diabetes mellitus and suspected coronary artery disease

Energy Technology Data Exchange (ETDEWEB)

Santos, Marcia Maria Sales dos; Pantoja, Mauricio da Rocha; Cwajg, Eduardo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); CINTILAB, Rio de Janeiro, RJ (Brazil); E-mail: mmsales@oi.com.br

2008-01-15

Background: The cardiovascular disease is the main cause of death among diabetic patients, which makes it crucial to identify the individuals at higher risk of cardiovascular events. Objective: To evaluate the prognostic value of scintigraphy with gated single photon emission computed tomography (SPECT) in patients with diabetes mellitus (DM) and suspected coronary artery disease. Methods: Retrospective study with 232 diabetic patients submitted to scintigraphy with gated SPECT. Perfusion Gated SPECT (scores and number of altered segments) as well as ventricular function parameters (ejection fraction, left ventricle volume and contractility) were evaluated. Cardiac death, acute ischemic coronary syndrome, revascularization procedures or encephalic vascular accident were considered future cardiovascular events. The uni- and multivariate analyses were carried out by the multiple logistic regression model (p< 0.05). Results: At the univariate analysis, age (p=0.02), chest angina (p=0.01), insulin therapy (p=0.02), myocardial perfusion abnormalities (p<0.0001), the number of segments involved (p=0.0001), the perfusion scores (p=0.0001), the ejection fraction (p=0.004), the final systolic volume (p=0.03) and the finding of segmental alteration at the LV contractility (p<0.0001) were associated with future events at the univariate analysis. At the multivariate analysis, the male sex (p=0.007), age (p=0.03), angina (p=0.001), insulin therapy (p=0.007) and the SDS {>=} 3 (p=0.0001), and the number of altered segments {>=} 3 (p=0.0001) were predictors of cardiovascular events. Conclusion: The myocardial scintigraphy with gated SPECT adds independent information to the stratification of the risk of future cardiovascular events in patients with DM and suspected coronary artery disease. (author)

Accessory left atrial diverticulae: contractile properties depicted with 64-slice cine-cardiac CT.

LENUS (Irish Health Repository)

Killeen, Ronan P

2012-02-01

To assess the contractility of accessory left atrial appendages (LAAs) using multiphasic cardiac CT. We retrospectively analyzed the presence, location, size and contractile properties of accessory LAAs using multiphasic cardiac 64-slice CT in 102 consecutive patients (63 males, 39 females, mean age 57). Multiplanar reformats were used to create image planes in axial oblique, sagittal oblique and coronal oblique planes. For all appendages with an orifice diameter >or= 10 mm, axial and sagittal diameters and appendage volumes were recorded in atrial diastole and systole. Regression analysis was performed to assess which imaging appearances best predicted accessory appendage contractility. Twenty-three (23%) patients demonstrated an accessory LAA, all identified along the anterior LA wall. Dimensions for axial oblique (AOD) and sagittal oblique (SOD) diameters and sagittal oblique length (SOL) were 6.3-19, 3.4-20 and 5-21 mm, respectively. All appendages (>or=10 mm) demonstrated significant contraction during atrial systole (greatest diameter reduction was AOD [3.8 mm, 27%]). Significant correlations were noted between AOD-contraction and AOD (R = 0.57, P < 0.05) and SOD-contraction and AOD, SOD and SOL (R = 0.6, P < 0.05). Mean diverticulum volume in atrial diastole was 468.4 +\\/- 493 mm(3) and in systole was 171.2 +\\/- 122 mm(3), indicating a mean change in volume of 297.2 +\\/- 390 mm(3), P < 0.0001. Stepwise multiple regression analysis revealed SOL to be the strongest independent predictor of appendage contractility (R(2) = 0.86, P < 0.0001) followed by SOD (R(2) = 0.91, P < 0.0001). Accessory LAAs show significant contractile properties on cardiac CT. Those accessory LAAs with a large sagittal height or depth should be evaluated for contractile properties, and if present should be examined for ectopic activity during electrophysiological studies.

Modulation of myocardial mitochondrial mechanisms during severe polymicrobial sepsis in the rat.

Directory of Open Access Journals (Sweden)

Mani Chopra

Full Text Available We tested the hypothesis that 5-Hydroxydecanoic acid (5HD, a putative mitoK(ATP channel blocker, will reverse sepsis-induced cardiodynamic and adult rat ventricular myocyte (ARVM contractile dysfunction, restore mitochondrial membrane permeability alterations and improve survival.Male Sprague-Dawley rats (350-400 g were made septic using 400 mg/kg cecal inoculum, ip. Sham animals received 5% dextrose water, ip. The Voltage Dependent Anion Channels (VDAC1, Bax and cytochrome C levels were determined in isolated single ARVMs obtained from sham and septic rat heart. Mitochondria and cytosolic fractions were isolated from ARVMs treated with norepinephrine (NE, 10 µmoles in the presence/absence of 5HD (100 µmoles. A continuous infusion of 5HD using an Alzet pump reversed sepsis-induced mortality when administered at the time of induction of sepsis (-40% and at 6 hr post-sepsis (-20%. Electrocardiography revealed that 5HD reversed sepsis-induced decrease in the average ejection fraction, Simpsons+m Mode (53.5±2.5 in sepsis and 69.2±1.2 at 24 hr in sepsis+5HD vs. 79.9±1.5 basal group and cardiac output (63.3±1.2 mL/min sepsis and 79.3±3.9 mL/min at 24 hr in sepsis+5HD vs. 85.8±1.5 mL/min basal group. The treatment of ARVMs with 5HD also reversed sepsis-induced depressed contractility in both the vehicle and NE-treated groups. Sepsis produced a significant downregulation of VDAC1, and upregulation of Bax levels, along with mitochondrial membrane potential collapse in ARVMs. Pretreatment of septic ARVMs with 5HD blocked a NE-induced decrease in the VDAC1 and release of cytochrome C.The data suggest that Bax activation is an upstream event that may precede the opening of the mitoK(ATP channels in sepsis. We concluded that mitoK(ATP channel inhibition via decreased mitochondrial membrane potential and reduced release of cytochrome C provided protection against sepsis-induced ARVM and myocardial contractile dysfunction.

Modulation of myocardial mitochondrial mechanisms during severe polymicrobial sepsis in the rat.

Science.gov (United States)

Chopra, Mani; Golden, Honey B; Mullapudi, Srinivas; Dowhan, William; Dostal, David E; Sharma, Avadhesh C

2011-01-01

We tested the hypothesis that 5-Hydroxydecanoic acid (5HD), a putative mitoK(ATP) channel blocker, will reverse sepsis-induced cardiodynamic and adult rat ventricular myocyte (ARVM) contractile dysfunction, restore mitochondrial membrane permeability alterations and improve survival. Male Sprague-Dawley rats (350-400 g) were made septic using 400 mg/kg cecal inoculum, ip. Sham animals received 5% dextrose water, ip. The Voltage Dependent Anion Channels (VDAC1), Bax and cytochrome C levels were determined in isolated single ARVMs obtained from sham and septic rat heart. Mitochondria and cytosolic fractions were isolated from ARVMs treated with norepinephrine (NE, 10 µmoles) in the presence/absence of 5HD (100 µmoles). A continuous infusion of 5HD using an Alzet pump reversed sepsis-induced mortality when administered at the time of induction of sepsis (-40%) and at 6 hr post-sepsis (-20%). Electrocardiography revealed that 5HD reversed sepsis-induced decrease in the average ejection fraction, Simpsons+m Mode (53.5±2.5 in sepsis and 69.2±1.2 at 24 hr in sepsis+5HD vs. 79.9±1.5 basal group) and cardiac output (63.3±1.2 mL/min sepsis and 79.3±3.9 mL/min at 24 hr in sepsis+5HD vs. 85.8±1.5 mL/min basal group). The treatment of ARVMs with 5HD also reversed sepsis-induced depressed contractility in both the vehicle and NE-treated groups. Sepsis produced a significant downregulation of VDAC1, and upregulation of Bax levels, along with mitochondrial membrane potential collapse in ARVMs. Pretreatment of septic ARVMs with 5HD blocked a NE-induced decrease in the VDAC1 and release of cytochrome C. The data suggest that Bax activation is an upstream event that may precede the opening of the mitoK(ATP) channels in sepsis. We concluded that mitoK(ATP) channel inhibition via decreased mitochondrial membrane potential and reduced release of cytochrome C provided protection against sepsis-induced ARVM and myocardial contractile dysfunction.

Selection of reference genes in different myocardial regions of an in vivo ischemia/reperfusion rat model for normalization of antioxidant gene expression

Directory of Open Access Journals (Sweden)

Vesentini Nicoletta

2012-02-01

Full Text Available Abstract Background Changes in cardiac gene expression due to myocardial injury are usually assessed in whole heart tissue. However, as the heart is a heterogeneous system, spatial and temporal heterogeneity is expected in gene expression. Results In an ischemia/reperfusion (I/R rat model we evaluated gene expression of mitochondrial and cytoplasmatic superoxide dismutase (MnSod, Cu-ZnSod and thioredoxin reductase (trxr1 upon short (4 h and long (72 h reperfusion times in the right ventricle (RV, and in the ischemic/reperfused (IRR and the remote region (RR of the left ventricle. Gene expression was assessed by Real-time reverse-transcription quantitative PCR (RT-qPCR. In order to select most stable reference genes suitable for normalization purposes, in each myocardial region we tested nine putative reference genes by geNorm analysis. The genes investigated were: Actin beta (actb, Glyceraldehyde-3-P-dehydrogenase (gapdh, Ribosomal protein L13A (rpl13a, Tyrosine 3-monooxygenase (ywhaz, Beta-glucuronidase (gusb, Hypoxanthine guanine Phosphoribosyltransferase 1 (hprt, TATA binding box protein (tbp, Hydroxymethylbilane synthase (hmbs, Polyadenylate-binding protein 1 (papbn1. According to our findings, most stable reference genes in the RV and RR were hmbs/hprt and hmbs/tbp/hprt respectively. In the IRR, six reference genes were recommended for normalization purposes; however, in view of experimental feasibility limitations, target gene expression could be normalized against the three most stable reference genes (ywhaz/pabp/hmbs without loss of sensitivity. In all cases MnSod and Cu-ZnSod expression decreased upon long reperfusion, the former in all myocardial regions and the latter in IRR alone. trxr1 expression did not vary. Conclusions This study provides a validation of reference genes in the RV and in the anterior and posterior wall of the LV of cardiac ischemia/reperfusion model and shows that gene expression should be assessed separately in

Proton chemical shift imaging after myocardial infarction

International Nuclear Information System (INIS)

Bouchard, A.; Doyle, M.; Pohost, G.M.

1989-01-01

The present study was undertaken to test whether chemical shift imaging could detect spatially the lipids known to accumulate in myocardium after an ischemic insult. Seven dogs underwent a 24-hour coronary artery occlusion. Hearts were removed and imaged ex vivo by the Dixon method (1.5 T), and myocardial samples were obtained for high-resolution H-1 spectroscopy. Lipid images revealed regions of increased signal intensity in the periphery f the myocardial infarction. The zones of high lipid signal corresponded to zones with elevated mobile lipids as detected by H-1 spectroscopy

Clinical use of 201Tl myocardial scintigraphy

International Nuclear Information System (INIS)

Senda, Kohei; Imaeda, Takeyoshi; Kato, Toshimitsu; Asada, Shuichi; Doi, Hidetaka

1977-01-01

Myocardial imaging with 201 Tl and scinticamera was studied experimentally using specially designed phantoms and clinically in 23 patients with myocardial infarction or other heart disease. In the phantom experiment, quality of image, accumulative count rate, and detectability of the defect were compared to obtain the best technique for their detection, using four different collimators, i.e., converging, pin-hole, 4000-hole, and 140 keV high-resolution, at two photopeak levels of 201 Tl of 75 and 167 keV, and combining a radiation absorber. In patient examination, myocardial images taken at different periods after injection, different detecting conditions of the scinticamera, and various detecting projections were compared. Images of the converging collimator at the 75 keV photopeak revealed considerably higher accumulative counts and relatively higher quality than those of other detecting conditions. It was necessary to take as many images as possible in various projections, in order to detect the location and size of the myocardial ischemic lesion because the lesion was demonstrated as a clear defect only in profile. It became evident that images taken between about 25 and 90 min delineated the myocardium more clearly than those taken in other periods. Normal images taken in 8 patients without ischemic heart disease appeared in the shape of a doughnut of horseshoe, demonstrating mainly the left venticular myocardium. The image was faint in the region of the aortic or mitral valve and thin in the region of the apical wall. A faint image of the right ventricular myocardium was sometimes seen. In 3 patients with valvular heart disease, findings suggested changes in the thickness of myocardium and the distribution of coronary blood flow. In 11 of 12 patients with old myocardial infarction, the location and size of the lesion was detected. (Evans, J.)

Myocardial perfusion scintigraphy with thallium-201 - principle and method

International Nuclear Information System (INIS)

Dressler, J.

1981-01-01

Since from the cardiological and cardio-surgical aspects non-invasive methods practicable in the diagnostics of regional myocardial blood perfusion are claiming priority, the myocardial perfusion scintigraphy with thallium 201 has gained more and more importance in the diagnostics of coronary heart diseases. Although radiothallium because of its nucleo-physical characteristics is not regarded as ideal radiopharmaceutical, it is at present, because of its potassium-analogue biokinetics the best radiopharmaceutical to represent the regional coronary perfusion distribution, the vitality and configuration of the heart muscle non-invasively. With careful clinical indication and under consideration of the physico-technical limitations, the informative value provided by the serial scintigraphy with thallium 201 is greater than that provided by the excercise ECG. Various possibilities for solving the problem of quantitative analysis of the myocardial scintigrams have been given. Up to the present day a standardised evaluation procedure corresponding to that of the visual scintigram interpretation has not yet found general acceptance. (orig.) [de

Myocardial viability in cases with persistent perfusion defects on the dipyridamole thallium-201 scintigram. A comparative study with autopsy findings

International Nuclear Information System (INIS)

Nakayama, Masafumi; Mashima, Saburo; Ohkawa, Shin-ichiro; Tanno, Munehiko; Yamada, Hideo.

1996-01-01

The aim of this study was to assess the incidence of myocardial infarction among persistent perfusion defects in dipyridamole-stress thallium scintigraphy by inspecting autopsied hearts and to evaluate whether the regional thallium activity of a scintigraphic defect can predict the presence of infarction. Autopsied hearts were compared with dipyridamole myocardial scintigrams undertaken during life in 27 patients (mean age 85±8 years). The time interval from stress testing until death was 428±351 days. Regional thallium uptake of delayed perfusion defect was calculated on the short axis images. The grade of regional myocardial fibrosis in autopsy specimens was also quantified to correlate with the corresponding regional thallium uptake. In 6 of 15 (40%) regions with persistent defects on the scintigram, myocardial infarction was not found at autopsy. Regional thallium-201 uptake of delayed defects < 50% diagnosed infarction with a sensitivity of 82% and a specificity of 80%. A linear correlation (r=-0.67) was observed between percent thallium-201 uptake and the degree of myocardial fibrosis. In conclusion, perfusion defects at 4-hour imaging in dipyridamole-stress testing may overestimate the presence of myocardial infarction and regional thallium-201 activity is helpful in distinguishing between defects with and without infarction. (author)

Sequential biventricular pacing improves regional contractility, longitudinal function and dyssynchrony in patients with heart failure and prolonged QRS

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Ring Margareta

2010-04-01

Full Text Available Abstract Aims Biventricular pacing (BiP is an effective treatment in systolic heart failure (HF patients with prolonged QRS. However, approximately 35% of the patients receiving BiP are classified as non-responders. The aim of this study is to evaluate the acute effects of VV-optimization on systolic heart function. Methods Twenty-one HF patients aged 72 (46-88 years, QRS 154 (120-190 ms, were studied with echocardiography, Tissue Doppler Imaging (TDI and 3D-echo the first day after receiving a BiP device. TDI was performed; during simultaneous pacing (LV-lead pacing 4 ms before the RV-lead and during sequential pacing (LV 20 and 40 ms before RV and RV 20 and 40 ms before LV-lead pacing. Systolic heart function was studied by tissue tracking (TT for longitudinal function and systolic maximal velocity (SMV for regional contractility and signs of dyssynchrony assessed by time-delays standard deviation of aortic valve opening to SMV, AVO-SMV/SD and tissue synchronization imaging (TSI. Results The TT mean value preoperatively was 4,2 ± 1,5 and increased at simultaneous pacing to 5,0 ± 1,2 mm (p Conclusions VV-optimization in the acute phase improves systolic heart function more than simultaneous BiP pacing. Long-term effects should be evaluated in prospective randomized trials.

Functional tests for myocardial ischemia

International Nuclear Information System (INIS)

Levinson, J.R.; Guiney, T.E.; Boucher, C.A.

1991-01-01

Functional tests for myocardial ischemia are numerous. Most depend upon a combination of either exercise or pharmacologic intervention with analysis of the electrocardiogram, of regional perfusion with radionuclide imaging, or of regional wall motion with radionuclide imaging or echocardiography. While each test has unique features, especially at the research level, they are generally quite similar in clinical practice, so the clinician is advised to concentrate on one or two in which local expertise is high.22 references

Prospective assessment of regional myocardial perfusion before and after coronary revascularization surgery by quantitative thallium-201 scintigraphy

International Nuclear Information System (INIS)

Gibson, R.S.; Watson, D.D.; Taylor, G.J.; Crosby, I.K.; Wellons, H.L.; Holt, N.D.; Beller, G.A.

1983-01-01

Because thallium-201 uptake relates directly to the amount of viable myocardium and nutrient blood flow, the potential for exercise scintigraphy to predict response to coronary revascularization surgery was investigated in 47 consecutive patients. All patients underwent thallium-201 scintigraphy and coronary angiography at a mean (+/- standard deviation) of 4.3 +/- 3.1 weeks before and 7.5 +/- 1.6 weeks after surgery. Thallium uptake and washout were computer-quantified and each of six segments was defined as normal, showing total or partial redistribution or a persistent defect. Persistent defects were further classified according to the percent reduction in regional thallium activity; PD25-50 denoted a 25 to 50% constant reduction in relative thallium activity and PD greater than 50 denoted a greater than 50% reduction. Of 82 segments with total redistribution before surgery, 76 (93%) showed normal thallium uptake and washout postoperatively, versus only 16 (73%) of 22 with partial redistribution (probability [p] . 0.01). Preoperative ventriculography revealed that 95% of the segments with total redistribution had preserved wall motion, versus only 74% of those with partial redistribution (p . 0.01). Of 42 persistent defects thought to represent myocardial scar before surgery, 19 (45%) demonstrated normal perfusion postoperatively. Of the persistent defects that showed improved thallium perfusion postoperatively, 75% had normal or hypokinetic wall motion before surgery, versus only 14% of those without improvement (p less than 0.001). Whereas 57% of the persistent defects that showed a 25 to 50% decrease in myocardial activity demonstrated normal thallium uptake and washout postoperatively, only 21% of the persistent defects with a decrease in myocardial activity greater than 50% demonstrated improved perfusion after surgery (p . 0.02)

Gene transfer of heterologous G protein-coupled receptors to cardiomyocytes: differential effects on contractility.

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Laugwitz, K L; Weig, H J; Moretti, A; Hoffmann, E; Ueblacker, P; Pragst, I; Rosport, K; Schömig, A; Ungerer, M

2001-04-13

In heart failure, reduced cardiac contractility is accompanied by blunted cAMP responses to beta-adrenergic stimulation. Parathyroid hormone (PTH)-related peptide and arginine vasopressin are released from the myocardium in response to increased wall stress but do not stimulate contractility or adenylyl cyclase at physiological concentrations. To bypass the defective beta-adrenergic signaling cascade, recombinant P1 PTH/PTH-related peptide receptors (rPTH1-Rs) and V(2) vasopressin receptors (rV(2)-Rs), which are normally not expressed in the myocardium and which are both strongly coupled to adenylyl cyclase, and recombinant beta(2)-adrenergic receptors (rbeta(2)-ARs) were overexpressed in cardiomyocytes by viral gene transfer. The capacity of endogenous hormones to increase contractility via the heterologous, recombinant receptors was compared. Whereas V(2)-Rs are uniquely coupled to Gs, PTH1-Rs and beta(2)-ARs are also coupled to other G proteins. Gene transfer of rPTH1-Rs or rbeta(2)-ARs to adult cardiomyocytes resulted in maximally increased basal contractility, which could not be further stimulated by adding receptor agonists. Agonists at rPTH1-Rs induced increased cAMP formation and phospholipase C activity. In contrast, healthy or failing rV(2)-R-expressing cardiomyocytes showed unaltered basal contractility. Their contractility and cAMP formation increased only at agonist exposure, which did not activate phospholipase C. In summary, we found that gene transfer of PTH1-Rs to cardiomyocytes results in constitutive activity of the transgene, as does that of beta(2)-ARS: In the absence of receptor agonists, rPTH1-Rs and rbeta(2)-ARs increase basal contractility, coupling to 2 G proteins simultaneously. In contrast, rV(2)-Rs are uniquely coupled to Gs and are not constitutively active, retaining their property to be activated exclusively on agonist stimulation. Therefore, gene transfer of V(2)-Rs might be more suited to test the effects of c

Suppression of guinea pig ileum induced contractility by plasma albumin of hibernators

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Bruce, David S.; Ambler, Douglas L.; Henschel, Timothy M.; Oeltgen, Peter R.; Nilekani, Sita P.; Amstrup, Steven C.

1992-01-01

Previous studies suggest that hibernation may be regulated by internal opioids and that the putative “hibernation induction trigger” (HIT) may itself be an opioid. This study examined the effect of plasma albumin (known to bind HIT) on induced contractility of the guinea pig ileum muscle strip. Morphine (400 nM) depressed contractility and 100 nM naloxone restored it. Ten milligrams of lyophilized plasma albumin fractions from hibernating ground squirrels, woodchucks, black bears, and polar bears produced similar inhibition, with partial reversal by naloxone. Five hundredths mg of d-Ala2-d-Leu5-enkephalin (DADLE) also inhibited contractility and naloxone reversed it. Conclusions are that hibernating individuals of these species contain an HIT substance that is opioid in nature and summer animals do not; an endogenous opioid similar to leu-enkephalin may be the HIT compound or give rise to it.

A global, myosin light chain kinase-dependent increase in myosin II contractility accompanies the metaphase-anaphase transition in sea urchin eggs.

Science.gov (United States)

Lucero, Amy; Stack, Christianna; Bresnick, Anne R; Shuster, Charles B

2006-09-01

Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase-anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase-anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus.

A Global, Myosin Light Chain Kinase-dependent Increase in Myosin II Contractility Accompanies the Metaphase–Anaphase Transition in Sea Urchin Eggs

Science.gov (United States)

Lucero, Amy; Stack, Christianna; Bresnick, Anne R.

2006-01-01

Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase–anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase–anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus. PMID:16837551

Left ventricular regional myocardial motion and twist function in repaired tetralogy of Fallot evaluated by magnetic resonance tissue phase mapping

International Nuclear Information System (INIS)

Chang, Meng-Chu; Peng, Hsu-Hsia; Wu, Ming-Ting; Weng, Ken-Pen; Su, Mao-Yuan; Menza, Marius; Huang, Hung-Chieh

2018-01-01

We aimed to characterise regional myocardial motion and twist function in the left ventricles (LV) in patients with repaired tetralogy of Fallot (rTOF) and preserved LV global function. We recruited 47 rTOF patients and 38 age-matched normal volunteers. Tissue phase mapping (TPM) was performed for evaluating the LV myocardial velocity in longitudinal, radial, and circumferential (Vz, Vr, and VOe) directions in basal, middle, and apical slices. The VOe peak-to-peak (PTP) during systolic phases, the rotation angle of each slice, and VOe inconsistency were computed for evaluating LV twist function and VOe dyssynchrony. As compared to the controls, the rTOF patients presented decreased RV ejection fraction (RVEF) (p = 0.002) and preserved global LV ejection fraction (LVEF). They also demonstrated decreased systolic and diastolic Vz in several LV segments and higher diastolic Vr in the septum (all p < 0.05). A lower VOe PTP, higher VOe inconsistency, and reduced peak net rotation angle (all p < 0.05) were observed. The aforementioned indices demonstrated an altered LV twist function in rTOF patients in an early disease stage. MR TPM could provide information about early abnormalities of LV regional motion and twist function in rTOF patients with preserved LV global function. (orig.)

Left ventricular regional myocardial motion and twist function in repaired tetralogy of Fallot evaluated by magnetic resonance tissue phase mapping

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Chang, Meng-Chu; Peng, Hsu-Hsia [National Tsing Hua University, Department of Biomedical Engineering and Environmental Sciences, Hsinchu (China); Wu, Ming-Ting [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (China); National Yang-Ming University, Faculty of Medicine, Taipei (China); Weng, Ken-Pen [National Yang-Ming University, Faculty of Medicine, Taipei (China); Kaohsiung Veterans General Hospital, Department of Pediatrics, Kaohsiung (China); Shu-Zen Junior College of Medicine and Management, Department of Physical Therapy, Kaohsiung (China); Su, Mao-Yuan [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Menza, Marius [Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Huang, Hung-Chieh [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (China)

2018-01-15

We aimed to characterise regional myocardial motion and twist function in the left ventricles (LV) in patients with repaired tetralogy of Fallot (rTOF) and preserved LV global function. We recruited 47 rTOF patients and 38 age-matched normal volunteers. Tissue phase mapping (TPM) was performed for evaluating the LV myocardial velocity in longitudinal, radial, and circumferential (Vz, Vr, and VOe) directions in basal, middle, and apical slices. The VOe peak-to-peak (PTP) during systolic phases, the rotation angle of each slice, and VOe inconsistency were computed for evaluating LV twist function and VOe dyssynchrony. As compared to the controls, the rTOF patients presented decreased RV ejection fraction (RVEF) (p = 0.002) and preserved global LV ejection fraction (LVEF). They also demonstrated decreased systolic and diastolic Vz in several LV segments and higher diastolic Vr in the septum (all p < 0.05). A lower VOe PTP, higher VOe inconsistency, and reduced peak net rotation angle (all p < 0.05) were observed. The aforementioned indices demonstrated an altered LV twist function in rTOF patients in an early disease stage. MR TPM could provide information about early abnormalities of LV regional motion and twist function in rTOF patients with preserved LV global function. (orig.)

Reliability of contractile properties of the knee extensor muscles in individuals with post-polio syndrome.

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Eric L Voorn

Full Text Available To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS and 18 age-matched healthy individuals.Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resistance, rate of torque development (MRTD, and early and late relaxation time (RT50 and RT25, using the intraclass correlation coefficient (ICC and standard error of measurement (SEM, expressed as % of the mean.In both groups, reliability for fatigue resistance was good, with high ICCs (>0.90 and small SEM values (PPS: 7.1%, healthy individuals: 7.0%. Reliability for contractile speed indices varied, with the best values found for RT50 (ICCs>0.82, SEM values <2.8%. We found no systematic differences between test and retest occasions, except for RT50 in healthy subjects (p = 0.016.In PPS and healthy individuals, the reliability of fatigue resistance, as obtained from electrically evoked contractions is high. The reliability of contractile speed is only moderate, except for RT50 in PPS, demonstrating high reliability.This was the first study to examine the reliability of electrically evoked contractile properties in individuals with PPS. Our results demonstrate its potential to study mechanisms underlying muscle fatigue in PPS and to evaluate changes in contractile properties over time in response to interventions or from natural course.

The use of coronary vasodilators in myocardial imaging with 43K

International Nuclear Information System (INIS)

Markov, A.K.; Smith, R.O.; Oglethorpe, N.C.; Lehan, P.H.; Hellems, H.K.

1980-01-01

As an alternative procedure to the exercise stress test used in myocardial scanning, vasoactive drugs were employed to elicit deficits in blood flow to myocardial regions supplied by stenotic arteries. The data were collected from 35 dogs, some of which had partial stenosis on either major branch of the left coronary artery, and others which had Ameroid constrictor implants. The effects of lidoflazine, dipyridamole, and nitroglycerin on coronary hemodynamics and myocardial dispersion of 43 K in animals with partial stenosis were evaluated in ten acute experiments. In the pilot studies, four rapid serial rectilinear control scans from 43 K (750 μCi) were reported; dipyridamole, lidoflazine, or nitroglycerin were then administered intravenously. When the selected drug reached a peak vasodilatative effect, a second equal bolus of 43 K was given and four additional scans recorded. The control scans from dogs with partial stenosis or an Ameroid constrictor showed homogeneous distribution of the myocardial 43 K. When drugs were used, the region supplied by compromised circulation became apparent because of lower counts when compared to the normally perfused ones. Coronary vasodilators, as opposed to postexercise in myocardial imaging, have a lesser effect on cardiac dynamics, peripheral hemodynamics, and also double the 43 K uptake in normally perfused myocardium. (orig.) [de

Diagnosis of coronary stenosis using thallium-201 myocardial emission computed tomography

International Nuclear Information System (INIS)

Ito, Tsunaaki; Takeda, Hiroshi; Maeda, Hisato; Nakagawa, Tsuyoshi; Yamaguchi, Nobuo; Makino, Katsutoshi; Futagami, Yasuo; Konishi, Tokuji

1985-01-01

Thallium-201 myocardial emission computed tomography (ECT) was described with respect to methods of correcting ECT data and reconstructing the images, qualitative and quantitative diagnosis in the detection of coronary stenosis. Although 201 Tl myocardial ECT (using circumferential profile method combined with washout method) has relatively high diagnostic sensitivity, the correction of absorption is not satisfactory yet. Inside absorption coefficient is considered uniform by regarding the human body as oval shape. However, the chest, including the heart, lungs, vertebrae and thoracic wall, has four different absorption coefficients. If absorption can be corrected accurately, it will be possible to completely assess the myocardial blood flow by measuring the regional myocardial uptake of thallium-201. (Namekawa, K.)

Protein kinase Cα deletion causes hypotension and decreased vascular contractility.

Science.gov (United States)

Wynne, Brandi M; McCarthy, Cameron G; Szasz, Theodora; Molina, Patrick A; Chapman, Arlene B; Webb, R Clinton; Klein, Janet D; Hoover, Robert S

2018-03-01

Protein kinase Cα (PKCα) is a critical regulator of multiple cell signaling pathways including gene transcription, posttranslation modifications and activation/inhibition of many signaling kinases. In regards to the control of blood pressure, PKCα causes increased vascular smooth muscle contractility, while reducing cardiac contractility. In addition, PKCα has been shown to modulate nephron ion transport. However, the role of PKCα in modulating mean arterial pressure (MAP) has not been investigated. In this study, we used a whole animal PKCα knock out (PKC KO) to test the hypothesis that global PKCα deficiency would reduce MAP, by a reduction in vascular contractility. Radiotelemetry measurements of ambulatory blood pressure (day/night) were obtained for 18 h/day during both normal chow and high-salt (4%) diet feedings. PKCα mice had a reduced MAP, as compared with control, which was not normalized with high-salt diet (14 days). Metabolic cage studies were performed to determine urinary sodium excretion. PKC KO mice had a significantly lower diastolic, systolic and MAP as compared with control. No significant differences in urinary sodium excretion were observed between the PKC KO and control mice, whether fed normal chow or high-salt diet. Western blot analysis showed a compensatory increase in renal sodium chloride cotransporter expression. Both aorta and mesenteric vessels were removed for vascular reactivity studies. Aorta and mesenteric arteries from PKC KO mice had a reduced receptor-independent relaxation response, as compared with vessels from control. Vessels from PKC KO mice exhibited a decrease in maximal contraction, compared with controls. Together, these data suggest that global deletion of PKCα results in reduced MAP due to decreased vascular contractility.

THE SPEKL-TREKING PREDICTIVE VALUE OF THE ECHOCARDIOGRAPHY AT THE ACUTE MYOCARDIAL INFARCTION

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N. A. Kosheleva

2016-01-01

Full Text Available Speckle-tracking echocardiography is a non-invasive method  for assessment of myocardial deformation, which is closely associated with its regional and global function. Although it is not yet introduced into clinical practice, deformation parameters are actively studied in different clinical conditions, particularly in acute myocardial infarction. Numerous studies show deformation  impairment may have important prognostic value at patients with a acute myocardial infarction.

Comparison of clinical tools for measurements of regional stress and rest myocardial blood flow assessed with 13N-ammonia PET/CT.

Science.gov (United States)

Slomka, Piotr J; Alexanderson, Erick; Jácome, Rodrigo; Jiménez, Moises; Romero, Edgar; Meave, Aloha; Le Meunier, Ludovic; Dalhbom, Magnus; Berman, Daniel S; Germano, Guido; Schelbert, Heinrich

2012-02-01

Several models for the quantitative analysis of myocardial blood flow (MBF) at stress and rest and myocardial flow reserve (MFR) with (13)N-ammonia myocardial perfusion PET have been implemented for clinical use. We aimed to compare quantitative results obtained from 3 software tools (QPET, syngo MBF, and PMOD), which perform PET MBF quantification with either a 2-compartment model (QPET and syngo MBF) or a 1-compartment model (PMOD). We considered 33 adenosine stress and rest (13)N-ammonia studies (22 men and 11 women). Average age was 54.5 ± 15 y, and average body mass index was 26 ± 4.2. Eighteen patients had a very low likelihood of disease, with no chest pain, normal relative perfusion results, and normal function. All data were obtained on a PET/CT scanner in list mode with CT attenuation maps. Sixteen dynamic frames were reconstructed (twelve 10-s, two 30-s, one 1-min, and one 6-min frames). Global and regional stress and rest MBF and MFR values were obtained with each tool. Left ventricular contours and input function region were obtained automatically in system QPET and syngo MBF and manually in PMOD. The flow values and MFR values were highly correlated among the 3 packages (R(2) ranging from 0.88 to 0.92 for global values and from 0.78 to 0.94 for regional values. Mean reference MFR values were similar for QPET, syngo MBF, and PMOD (3.39 ± 1.22, 3.41 ± 0.76, and 3.66 ± 1.19, respectively) by 1-way ANOVA (P = 0.74). The lowest MFR in very low likelihood patients in any given vascular territory was 2.25 for QPET, 2.13 for syngo MBF, and 2.23 for PMOD. Different implementations of 1- and 2-compartment models demonstrate an excellent correlation in MFR for each vascular territory, with similar mean MFR values.

Myocardial Bridging

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Shi-Min Yuan

2016-02-01

Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

Protective effect of hydroalcoholic extract of Andrographis paniculata on ischaemia-reperfusion induced myocardial injury in rats.

Science.gov (United States)

Ojha, Shreesh Kumar; Bharti, Saurabh; Joshi, Sujata; Kumari, Santosh; Arya, Dharamvir Singh

2012-03-01

Protecting myocardium from ischaemia-reperfusion (I-R) injury is important to reduce the complication of myocardial infarction (MI) and interventional revascularization procedures. In the present study, the cardioprotective potential of hydroalcoholic extract of Andrographis paniculata was evaluated against left anterior descending coronary artery (LADCA) ligation-induced I-R injury of myocardium in rats. MI was induced in rats by LADCA ligation for 45 min followed by reperfusion for 60 min. The rats were divided into five experimental groups viz., sham (saline treated, but LADCA was not ligated), I-R control (saline treated + I-R), benazepril (30 mg/kg + I-R), A. paniculata (200 mg/kg per se) and A. paniculata (200 mg/kg + I-R). A. paniculata was administered orally for 31 days. On day 31, rats were subjected to the I-R and cardiac function parameters were recorded. Further, rats were sacrificed and heart was excised for biochemical and histopathological studies. In I-R control group, LADCA ligation resulted in significant cardiac dysfunction evidenced by reduced haemodynamic parameters; mean arterial pressure (MAP) and heart rate (HR). The left ventricular contractile function was also altered. In I-R control group, I-R caused decline in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH) as well as leakage of myocytes injury marker enzymes, creatine phosphokinase-MB (CK-MB) isoenzyme and lactate dehydrogenase (LDH), and enhanced lipid peroxidation product, malonaldialdehyde (MDA). However, rats pretreated with A. paniculata 200 mg/kg showed favourable modulation of haemodynamic and left ventricular contractile function parameters, restoration of the myocardial antioxidants and prevention of depletion of myocytes injury marker enzymes along with inhibition of lipid peroxidation. Histopathological observations confirmed the protective effects of A. paniculata. The cardioprotective effects of A. paniculata were

Myocardial perfusion in type 2 diabetes with left ventricular hypertrophy

DEFF Research Database (Denmark)

Hesse, Birger; Meyer, Christian; Nielsen, Flemming S

2004-01-01

The purpose of this study was to assess whether acute angiotensin-converting enzyme (ACE) inhibition would improve myocardial perfusion and perfusion reserve in a subpopulation of normotensive patients with diabetes and left ventricular hypertrophy (LVH), both independent risk factors of coronary...... disease. Using positron emission tomography (PET), we investigated the response of regional myocardial perfusion to acute ACE inhibition with i.v. infusion of perindoprilat (vs saline infusion as control, minimum interval 3 days) in 12 diabetic patients with LVH. Myocardial perfusion was quantified...... with controls, maximal perfusion was reduced in patients (1.8+/-0.6 vs 2.5+/-1.0 ml min(-1) g(-1); P2.7+/-1.0 vs 3.6+/-1.3; P=0.059). During perindoprilat infusion, myocardial perfusion reserve in patients increased to 3.9+/-0.9 ( P

Incidence, Frequency, and Clinical Characteristics of Type 3 Myocardial Infarction in Clinical Practice

DEFF Research Database (Denmark)

Jangaard, Nikolaj; Sarkisian, Laura; Saaby, Lotte

2017-01-01

the Danish Register of Causes of Death, ambulance and hospital patient files. Adjudication of the diagnosis was done by two local experts and one external senior cardiologist. RESULTS: A total of 2766 of the 246.723 adult residents in the region had died. A type 3 myocardial infarction was diagnosed in 18...... individuals, corresponding to an annual incidence of 7.3/100.000 person years. During the same one-year period 488 patients had other types of myocardial infarction implying a 3.6% frequency of type 3 myocardial infarction (18 of 506) among all myocardial infarctions. CONCLUSIONS: Type 3 myocardial infarction...... is a rare observation in clinical practice with an annual incidence below 10/100.000 person years and a frequency of 3-4% among all types of myocardial infarction. If autopsy data are included the number of type 3 myocardial infarctions will increase....

Tomographic myocardial perfusion scintigraphy in children with Kawasaki disease

International Nuclear Information System (INIS)

Spielmann, R.P.; Nienaber, C.A.; Hausdorf, G.; Montz, R.

1987-01-01

Myocardial infarction and stenotic coronary lesions are serious late complications in children with Kawasaki disease. For the noninvasive assessment of myocardial perfusion, dipyridamole-redistribution 201 Tl emission computed tomography (ECT) was performed in seven children (age 2 8/12-8 7/12 yr) 3-20 mo after the acute stage of the disease. In all patients, coronary aneurysms had been demonstrated by cross-sectional echocardiography. The scintigrams of six children showed no significant regional reduction of myocardial thallium uptake. These children had remained asymptomatic since the acute stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with documented myocardial infarction. For this patient, obstruction of corresponding coronary vessels was confirmed by contrast angiography. It is suggested, that 201 Tl ECT after dipyridamole-induced vasodilation may be used as a safe alternative to invasive coronary angiography for follow-up investigations in patients with Kawasaki disease

PKA catalytic subunit compartmentation regulates contractile and hypertrophic responses to β-adrenergic signaling

Science.gov (United States)

Yang, Jason H.; Polanowska-Grabowska, Renata K.; Smith, Jeffrey S.; Shields, Charles W.; Saucerman, Jeffrey J.

2014-01-01

β-adrenergic signaling is spatiotemporally heterogeneous in the cardiac myocyte, conferring exquisite control to sympathetic stimulation. Such heterogeneity drives the formation of protein kinase A (PKA) signaling microdomains, which regulate Ca2+ handling and contractility. Here, we test the hypothesis that the nucleus independently comprises a PKA signaling microdomain regulating myocyte hypertrophy. Spatially-targeted FRET reporters for PKA activity identified slower PKA activation and lower isoproterenol sensitivity in the nucleus (t50 = 10.60±0.68 min; EC50 = 89.00 nmol/L) than in the cytosol (t50 = 3.71±0.25 min; EC50 = 1.22 nmol/L). These differences were not explained by cAMP or AKAP-based compartmentation. A computational model of cytosolic and nuclear PKA activity was developed and predicted that differences in nuclear PKA dynamics and magnitude are regulated by slow PKA catalytic subunit diffusion, while differences in isoproterenol sensitivity are regulated by nuclear expression of protein kinase inhibitor (PKI). These were validated by FRET and immunofluorescence. The model also predicted differential phosphorylation of PKA substrates regulating cell contractility and hypertrophy. Ca2+ and cell hypertrophy measurements validated these predictions and identified higher isoproterenol sensitivity for contractile enhancements (EC50 = 1.84 nmol/L) over cell hypertrophy (EC50 = 85.88 nmol/L). Over-expression of spatially targeted PKA catalytic subunit to the cytosol or nucleus enhanced contractile and hypertrophic responses, respectively. We conclude that restricted PKA catalytic subunit diffusion is an important PKA compartmentation mechanism and the nucleus comprises a novel PKA signaling microdomain, insulating hypertrophic from contractile β-adrenergic signaling responses. PMID:24225179

The Functional Lumen Imaging Probe Detects Esophageal Contractility not Observed with Manometry in Patients with Achalasia

Science.gov (United States)

Carlson, Dustin A.; Lin, Zhiyue; Kahrilas, Peter J.; Sternbach, Joel; Donnan, Erica N.; Friesen, Laurel; Listernick, Zoe; Mogni, Benjamin; Pandolfino, John E.

2015-01-01

Background & Aims The functional lumen imaging probe (FLIP) could improve characterization of achalasia subtypes by detecting non-occlusive esophageal contractions not observed with standard manometry. We aimed to evaluate for esophageal contractions during volumetric distention in patients with achalasia using FLIP topography. Methods Fifty one treatment-naïve patients with achalasia, defined and sub-classified by high-resolution esophageal pressure topography, and 10 asymptomatic individuals (controls) were evaluated with the FLIP during endoscopy. During stepwise distension, simultaneous intra-bag pressures and 16 channels of cross-sectional areas were measured; data were exported to software that generated FLIP topography plots. Esophageal contractility was identified by noting periods of reduced luminal diameter. Esophageal contractions were further characterized by propagation direction, repetitiveness, and based on whether they were occluding or non-occluding. Results Esophageal contractility was detected in all 10 controls: 8/10 had repetitive, antegrade, contractions and 9/10 had occluding contractions. Contractility was detected in 27% (4/15) of patients with type I achalasia and 65% (18/26, including 9 with occluding contractions) of patients with type II achalasia. Contractility was detected in all 10 patients with type III achalasia; 8 of these patients had a pattern of contractility not observed in controls (repetitive, retrograde contractions). Conclusions Esophageal contractility not observed with manometry can be detected in patients with achalasia using FLIP topography. The presence and patterns of contractility detected with FLIP topography may represent variations in pathophysiology, such as mechanisms of pan-esophageal pressurization in patients with type II achalasia. These findings could have implications for additional sub-classification to supplement prediction of the achalasia disease course. PMID:26278501

Impaired right ventricular contractile function in childhood obesity and its association with right and left ventricular changes: a cine DENSE cardiac magnetic resonance study.

Science.gov (United States)

Jing, Linyuan; Pulenthiran, Arichanah; Nevius, Christopher D; Mejia-Spiegeler, Abba; Suever, Jonathan D; Wehner, Gregory J; Kirchner, H Lester; Haggerty, Christopher M; Fornwalt, Brandon K

2017-06-28

Pediatric obesity is a growing public health problem, which is associated with increased risk of cardiovascular disease and premature death. Left ventricular (LV) remodeling (increased myocardial mass and thickness) and contractile dysfunction (impaired longitudinal strain) have been documented in obese children, but little attention has been paid to the right ventricle (RV). We hypothesized that obese/overweight children would have evidence of RV remodeling and contractile dysfunction. One hundred and three children, ages 8-18 years, were prospectively recruited and underwent cardiovascular magnetic resonance (CMR), including both standard cine imaging and displacement encoding with stimulated echoes (DENSE) imaging, which allowed for quantification of RV geometry and function/mechanics. RV free wall longitudinal strain was quantified from the end-systolic four-chamber DENSE image. Linear regression was used to quantify correlations of RV strain with LV strain and measurements of body composition (adjusted for sex and height). Analysis of variance was used to study the relationship between RV strain and LV remodeling types (concentric remodeling, eccentric/concentric hypertrophy). The RV was sufficiently visualized with DENSE in 70 (68%) subjects, comprising 36 healthy weight (13.6 ± 2.7 years) and 34 (12.1 ± 2.9 years) obese/overweight children. Obese/overweight children had a 22% larger RV mass index (8.2 ± 0.9 vs 6.7 ± 1.1 g/m 2.7 , p right ventricles in obese/overweight children.

Clinical Characteristics and Associated Systemic Diseases in Patients With Esophageal "Absent Contractility"-A Clinical Algorithm.

Science.gov (United States)

Laique, Sobia; Singh, Tavankit; Dornblaser, David; Gadre, Abhishek; Rangan, Vikram; Fass, Ronnie; Kirby, Donald; Chatterjee, Soumya; Gabbard, Scott

2018-01-19

This study was carried out to assess the clinical characteristics and associated systemic diseases seen in patients diagnosed with absent contractility as per the Chicago Classification version 3.0, allowing us to propose a diagnostic algorithm for their etiologic testing. The Chicago Classification version 3.0 has redefined major and minor esophageal motility disorders using high-resolution esophageal manometry. There is a dearth of publications based on research on absent contractility, which historically has been associated with myopathic processes such as systemic sclerosis (SSc). We conducted a retrospective, multicenter study. Data of patients diagnosed with absent contractility were pooled from Cleveland Clinic, Cleveland, OH (January 2006 to July 2016) and Metrohealth Medical Center, Cleveland, OH (July 2014 to July 2016) and included: age, gender, associated medical conditions, surgical history, medications, and specific antibody testing. A total of 207 patients, including 57 male individuals and 150 female individuals, with mean age of 56.1 and 60.0 years, respectively, were included. Disease distribution was as follows: SSc (diffuse or limited cutaneous) 132, overlap syndromes 7, systemic lupus erythematosus17, Sjögren syndrome 4, polymyositis 3, and dermatomyositis 3. Various other etiologies including gastroesophageal reflux disease, postradiation esophagitis, neuromuscular disorders, and surgical complications were seen in the remaining cohort. Most practitioners use the term "absent contractility" interchangeably with "scleroderma esophagus"; however, only 63% of patients with absent contractility had SSc. Overall, 20% had another systemic autoimmune rheumatologic disease and 16% had a nonrheumatologic etiology for absent contractility. Therefore, alternate diagnosis must be sought in these patients. We propose an algorithm for their etiologic evaluation.

Inhalation of Budesonide/Formoterol Increases Diaphragm Muscle Contractility

Directory of Open Access Journals (Sweden)

Chiyohiko Shindoh

2012-01-01

Conclusions: BUD/FORM inhalation has an inotropic effect on diaphragm muscle, protects diaphragm muscle deterioration after endotoxin injection, and inhibits NO production. Increments in muscle contractility with BUD/FORM inhalation are induced through a synergistic effect of an anti-inflammatory agent and 02-agonist.

Serial thallium-201 imaging after dipyridamole for coronary disease detection: quantitative analysis using myocardial clearance

International Nuclear Information System (INIS)

Okada, R.D.; Dai, Y.H.; Boucher, C.A.; Pohost, G.M.

1984-01-01

After dipyridamole, canine studies have demonstrated a slower rate of myocardial thallium-201 clearance from zones distal to a coronary artery stenosis compared to normal zones. To determine if criteria based on canine myocardial thallium-201 clearance rates could be applied clinically, 40 patients with and 26 patients without coronary artery disease (CAD) had serial thallium-201 images obtained for 2 to 5 hours after dipyridamole. Regions of interest were manually placed over six left ventricular segments in two projections for each of three imaging times. The myocardial thallium-201 clearance rate was calculated for each of the six segments and, using the clearance rate criterion found in canine studies, was considered abnormal if less than 6.5%/hr. Using this criterion alone, 22 of 26 patients (85%) without CAD had normal and 30 of 40 patients (75%) with CAD had abnormal myocardial thallium-201 clearance rates. A quantitative analysis of regional inhomogeneity in tracer distribution (normal was greater than or equal to 25% difference between segments) was negative in 24 of 26 patients (92%) without CAD and positive in 20 of 40 patients (50%) with CAD. When both clearance rate and regional inhomogeneity were considered, 21 of 26 patients (81%) without CAD had negative and 36 of 40 patients (90%) with CAD had positive results. Thus, post-dipyridamole myocardial clearance rate criteria derived from canine studies can be applied to clinical thallium imaging. Quantitative analysis of serial thallium-201 images after dipyridamole is optimized by using myocardial thallium-201 clearance rates. Such an approach is independent of regional inhomogeneities in tracer distribution

Detection of hibernating myocardium in patients with myocardial infarction by low-dose dobutamine echocardiography. Comparison with thallium-201 scintigraphy with reinjection

International Nuclear Information System (INIS)

Takagi, Tsutomu; Yoshikawa, Junichi; Yoshida, Kiyoshi; Akasaka, Takashi; Honda, Yasuhiro; Yonezawa, Yoshihiro; Shakudo, Masahiro

1995-01-01

The identification of hibernating myocardium is important for selecting patients who will benefit from coronary revascularization. The relationship between echocardiographic and radioisotopic markers of hibernating myocardium and postrevascularization recovery of myocardial function was investigated in 21 patients who underwent successful revascularization. Each patient underwent low-dose dobutamine stress echocardiography and thallium-201 ( 201 Tl) scintigraphy with reinjection before revascularization. The presence of contractile reserve in dobutamine stress echocardiography and Tl uptake in 201 Tl scintigraphy with reinjection were defined as markers of hibernating myocardium. Follow-up echocardiograms were evaluated for improved regional wall motion in all patients at a mean of 8.6 months after revascularization. Sensitivity, specificity, and positive and negative predictive values of low-dose dobutamine stress echocardiography for indicating recovery of function after revascularization were 75.0%, 77.8%, 81.8%, and 70.0%, respectively. Sensitivity, specificity, and positive and negative predictive values of 201 Tl scintigraphy with reinjection for indicating recovery of function after revascularization were 91.7%, 55.6%, 73.3%, and 83.3%, respectively. There were no statistical differences between low-dose dobutamine echocardiography and 201 Tl scintigraphy in predicting postrevascularization recovery of function in patients with hibernating myocardium. (author)

Clinical indications for Thallium-201 myocardial perfusion scanning

International Nuclear Information System (INIS)

Dunn, R.J.; Kelly, D.T.

1982-01-01

Thallium-201 myocardial perfusion scanning can assess regional myocardial perfusion non-invasively. As it is both time-consuming and expensive its use should be restricted to specific diagnostic problems. The clinical indications in known or suspected coronary artery disease are reviewed. In suspected coronary artery disease thallium scanning is most useful in patients with chest pain when the exercise ECG is uninterpretable, in men with probable angina but a negative exercise ECG, or conversely a positive exercise ECG without typical angina, and in women with probable angina and either a positive or a negative exercise ECG. In known coronary artery disease, thallium scanning may help determine the functional significance of a coronary obstruction found at angiography and may determine the site of myocardial ischaemia when multiple obstructions are present

MR tomography in myocardial ischaemia: present state of the art

International Nuclear Information System (INIS)

Szolar, D.H.; Saeed, M.; Higgins, C.B.

1996-01-01

Recent developments in MR imaging have opened up new avenues in the investigation of ischaemic heart disease. Conventional unenhanced spin-echo sequences have been used to detect and quantify myocardial infarction. Along with the technical advances aimed at reducing motion artifacts and imaging time, the advent of contrast media for MR imaging has further strengthened its diagnostic capacities. The applications of MR contrast media are increasing, and they are becoming more specific, to enable differentiation of occlusive and reperfused myocardial infarctions and to discriminate between reversible and irreversible myocardial injury. Previous studies have also indicated that dual administration of both relaxivity-based and susceptibility-based contrast media can be used to determine whether viable myocardium is present in the reperfused ischaemic area. Magnetic susceptibility MR contrast media have the potential to demonstrate a region of the ischaemically injured myocardium in which myocardial necrosis is present. A cornestone in the MR assessment of ischaemic heart disease has been achieved with the advent of fast MR imaging techniques. Ultrafast gradient-recalled-echo sequences or echoplanar imaging allow to monitor the first passage of the contrast medium through the heart. With the aid of MR contrast media, these techniques may be useful in estimating regional myocardial perfusion and blood volume. Experimental and clinical perfusion studies indicate that perfusion-sensitive MR imaging, particularly in concert with coronary vasodilators, can detect compromised myocardium. Combining myocardial perfusion imaging with the anatomic and functional information provided by other MR imaging techniques such as cine and velocity-encoded sequences could make MR imaging a comprehensive noninvasive diagnostic tool for the assessment of ischaemic heart disease. (orig.) [de

Effect of glucose-insulin-potassium infusion on thallium myocardial clearance

International Nuclear Information System (INIS)

Wilson, R.A.; Okada, R.D.; Strauss, H.W.; Pohost, G.M.

1983-01-01

Factors influencing the rate of 201 Tl clearance from the myocardium have not been clearly defined. This study determined the effect of an intravenous infusion of glucose-insulin-potassium (GIK) on the net 201 Tl clearance rates from myocardium with and without initial 201 Tl loading. Anesthetized open-chest dogs underwent 5 min of left anterior descending coronary artery occlusion and intravenous 201 Tl was injected and the occlusion released 5 min later. Thirty minutes after 201 Tl injection, 30 ml of either GIK (nine dogs) or saline (five dogs) was infused intravenously. The clearance rates of 201 Tl from the anterior wall (without initial 201 Tl loading) and from the posterior wall (with initial 201 Tl loading) were monitored with miniaturized cadmium telluride detectors placed on the myocardium. Calculation of net myocardial clearance rates was performed by linear regression analysis from serial 1 min counts. Compared with saline infusion, GIK increased the net clearance of 201 Tl from both myocardial regions with and without initial loading. The most marked change induced by GIK infusion was in the myocardial region without initial 201 Tl loading; a net increase in 201 Tl activity (72 +/- 42 cpm/30 min) was converted into a net loss (-594 +/- 228 cpm/30 min). There was no significant change in 201 Tl clearance after the saline infusion. Heart rate, aortic and left atrial pressure, sonomicrometer-measured transmural myocardial wall thickness, microsphere-determined myocardial blood flow, and blood glucose and potassium concentrations did not change significantly during GIK or saline infusions. Thus, GIK infusion appears to increase net 201 Tl clearance from myocardial zones with and without initial 201 Tl loading

Myocardial viability assessed with fluorodeoxyglucose and PET in patients with Q wave myocardial infarction receiving thrombolysis: relationship to coronary anatomy and ventricular function.

Science.gov (United States)

Fragasso, G; Chierchia, S L; Rossetti, E; Sciammarella, M G; Conversano, A; Lucignani, G; Landoni, C; Calori, G; Margonato, A; Fazio, F

1997-03-01

In previously thrombolysed patients, we analysed residual myocardial viability using the PET-FDG technique and correlated its presence and extent to the angiographic appearance of the infarct-related vessel and left ventricular function. Thirty-six patients who had undergone intravenous thromboloysis for acute myocardial infarction 4.8 +/- 7.2 months previously were studied. Coronary angiography, left ventriculography, and assessment of myocardial perfusion and metabolism were all performed within 1 week. All patients exhibited perfusion defects consistent with the clinically identified myocardial infarction site. Residual viability, as assessed by the PET-FDG technique, was present in 53% of cases. The infarct-related coronary artery was patent in 19 (53%) patients (TIMI grade 3, 79%); of the remaining 17 with occluded infarct-related arteries, 11 had collaterals to the infarct area. Significant FDG uptake was observed in 63% of patients with a patent infarct-related artery and in 41% of those with an occluded infarct-related artery. The same study protocol was adopted in a control group of 30 patients with myocardial infarction who did not receive thrombolysis. The number of infarct-related patent vessels was significantly lower in these patients (30 vs 53%) (TIMI grade 3, 56%), but the overall percentage of PET viability was again 53%. Qualitative analysis of the regional perfusion pattern showed that the magnitude and severity of the perfusion defect was similar in the two groups, regardless of the presence or absence of FDG uptake. Global left ventricular function was also similar in the two groups. However, regional wall motion was significantly better in the thrombolysed patients with a patent infarct-related artery than in those who had not received thrombolysis and whose culprit vessel was also patent. In conclusion, the results of our study support the notion that early recanalization of the infarct-related artery is critical for preserving left

Clinical evaluation of myocardial involvement in acute myopericarditis in young adults.

Science.gov (United States)

Saricam, Ersin; Saglam, Yasemin; Hazirolan, Tuncay

2017-05-22

Myocardial involvement in young adults has various causes. Acute myopericarditis is one of the myocardial involvements in young adults. It is easy to confuse with acute ST-elevation myocardial infarction because of the electrocardiographic features. This study aims to investigate a number of imaging techniques and clinical features for acute myopericarditis in young adults (defined as myocardial brightness in the left ventricle regions, especially in posterior and lateral wall. Focal echobright was observed in the 75 of 77 cases of acute myopericarditis in transthoracic echocardiogram. This sign was confirmed by cardiac magnetic resonance imaging. Focal echobright sensitivity was 95%; its specificity was 93%; its predictive was 95.2%. Pericardial effusion (83%) was observed in group I behind posterior wall. Its specificity was 81%; its sensitivity was 65%; predictivity was 73%. Pericardial effusion and myocardial focal echobright in echocardiography can be quite sensitive indicators for acute myopericarditis in young adults.

Heart deformation analysis for automated quantification of cardiac function and regional myocardial motion patterns: A proof of concept study in patients with cardiomyopathy and healthy subjects

Energy Technology Data Exchange (ETDEWEB)

Lin, Kai, E-mail: kai-lin@northwestern.edu; Collins, Jeremy D.; Chowdhary, Varun; Markl, Michael; Carr, James C.

2016-10-15

Highlights: • Heart deformation analysis (HDA) can quantify global and regional cardiac function. • HDA works based on cine CMR images without the needs of operator interaction. • HDA-derived cardiac motion indices are reproducible. - Abstract: Objective: To test the performance of HDA in characterizing left ventricular (LV) function and regional myocardial motion patterns in the context of cardiomyopathy based on cine cardiovascular magnetic resonance (CMR). Materials and methods: Following the approval of the institutional review board (IRB), standard cine images of 45 subjects, including 15 healthy volunteers, 15 patients with hypertrophic cardiomyopathy (HCM) and 15 patients with dilated cardiomyopathy (DCM) were retrospectively analyzed using HDA. The variations of LV ejection fraction (LVEF), LV mass (LVM), and regional myocardial motion indices, including radial (Drr), circumferential (Dcc) displacement, radial (Vrr) and circumferential (Vcc) velocity, radial (Err), circumferential (Ecc) and shear (Ess) strain and radial (SRr) and circumferential (SRc) strain rate, were calculated and compared among subject groups. Inter-study reproducibility of HDA-derived myocardial motion indices were tested on 15 volunteers by using intra-class correlation coefficient (ICC) and coefficient of variation (CoV). Results: HDA identified significant differences in cardiac function and motion indices between subject groups. DCM patients had significantly lower LVEF (33.5 ± 9.65%), LVM (105.88 ± 21.93 g), peak Drr (0.29 ± 0.11 cm), Vrr-sys (2.14 ± 0.72 cm/s), Err (0.17 ± 0.08), Ecc (−0.08 ± 0.03), SRr-sys (0.91 ± 0.44s{sup −1}) and SRc-sys (−0.64 ± 0.27s{sup −1}) compared to the other two groups. HCM patients demonstrated increased LVM (171.69 ± 34.19) and lower peak Vcc-dia (0.78 ± 0.30 cm/s) than other subjects. Good inter-study reproducibility was found for all HDA-derived myocardial indices in healthy volunteers (ICC = 0.664–0.942, CoV = 15.1%–37

Heart deformation analysis for automated quantification of cardiac function and regional myocardial motion patterns: A proof of concept study in patients with cardiomyopathy and healthy subjects

International Nuclear Information System (INIS)

Lin, Kai; Collins, Jeremy D.; Chowdhary, Varun; Markl, Michael; Carr, James C.

2016-01-01

Highlights: • Heart deformation analysis (HDA) can quantify global and regional cardiac function. • HDA works based on cine CMR images without the needs of operator interaction. • HDA-derived cardiac motion indices are reproducible. - Abstract: Objective: To test the performance of HDA in characterizing left ventricular (LV) function and regional myocardial motion patterns in the context of cardiomyopathy based on cine cardiovascular magnetic resonance (CMR). Materials and methods: Following the approval of the institutional review board (IRB), standard cine images of 45 subjects, including 15 healthy volunteers, 15 patients with hypertrophic cardiomyopathy (HCM) and 15 patients with dilated cardiomyopathy (DCM) were retrospectively analyzed using HDA. The variations of LV ejection fraction (LVEF), LV mass (LVM), and regional myocardial motion indices, including radial (Drr), circumferential (Dcc) displacement, radial (Vrr) and circumferential (Vcc) velocity, radial (Err), circumferential (Ecc) and shear (Ess) strain and radial (SRr) and circumferential (SRc) strain rate, were calculated and compared among subject groups. Inter-study reproducibility of HDA-derived myocardial motion indices were tested on 15 volunteers by using intra-class correlation coefficient (ICC) and coefficient of variation (CoV). Results: HDA identified significant differences in cardiac function and motion indices between subject groups. DCM patients had significantly lower LVEF (33.5 ± 9.65%), LVM (105.88 ± 21.93 g), peak Drr (0.29 ± 0.11 cm), Vrr-sys (2.14 ± 0.72 cm/s), Err (0.17 ± 0.08), Ecc (−0.08 ± 0.03), SRr-sys (0.91 ± 0.44s −1 ) and SRc-sys (−0.64 ± 0.27s −1 ) compared to the other two groups. HCM patients demonstrated increased LVM (171.69 ± 34.19) and lower peak Vcc-dia (0.78 ± 0.30 cm/s) than other subjects. Good inter-study reproducibility was found for all HDA-derived myocardial indices in healthy volunteers (ICC = 0.664–0.942, CoV = 15.1%–37

Direct myocardial perfusion imaging in valvular heart disease

Energy Technology Data Exchange (ETDEWEB)

Soto, R.C.; Durante, M.L.; Villacorta, E.V.; Torres, J.F.; Monzon, O.P.

1981-02-01

Twenty two patients with rheumatic valvular heart disease - 21 having a history of heart failure - were studied using direct coronary injection of /sup 99m/Tc labelled MAA particles during the course of hemodynamic and arteriographic studies. Myocardial perfusion deficit patterns have been shown to be consistent or indicative of either patchy, regional or gross ischemia. In patients with history of documented heart failure 90% (18 cases) had ischemic perfusion deficit in the involved ventricle. We conclude that diminished myocardial blood flow is an important mechanism contributing to the development of heart failure.

Direct myocardial perfusion imaging in valvular heart disease

International Nuclear Information System (INIS)

Soto, R.C.; Durante, M.L.; Villacorta, E.V.; Torres, J.F.; Monzon, O.P.

1981-01-01

Twenty two patients with rheumatic valvular heart disease - 21 having a history of heart failure - were studied using direct coronary injection of sup(99m)Tc labelled MAA particles during the course of hemodynamic and arteriographic studies. Myocardial perfusion deficit patterns have been shown to be consistent or indicative of either patchy, regional or gross ischemia. In patients with history of documented heart failure 90% (18 cases) had ischemic perfusion deficit in the involved ventricle. We conclude that diminished myocardial blood flow is an important mechanism contributing to the development of heart failure. (orig.) [de

Clinical use of /sup 201/Tl myocardial scintigraphy

Energy Technology Data Exchange (ETDEWEB)

Senda, K; Imaeda, T; Kato, T; Asada, S; Doi, H

1977-04-01

Myocardial imaging with /sup 201/Tl and scinticamera was studied experimentally using specially designed phantoms and clinically in 23 patients with myocardial infarction or other heart disease. In the phantom experiment, quality of image, accumulative count rate, and detectability of the defect were compared to obtain the best technique for their detection, using four different collimators, i.e., converging, pin-hole, 4000-hole, and 140 keV high-resolution, at two photopeak levels of /sup 201/Tl of 75 and 167 keV, and combining a radiation absorber. In patient examination, myocardial images taken at different periods after injection, different detecting conditions of the scinticamera, and various detecting projections were compared. Images of the converging collimator at the 75 keV photopeak revealed considerably higher accumulative counts and relatively higher quality than those of other detecting conditions. It was necessary to take as many images as possible in various projections, in order to detect the location and size of the myocardial ischemic lesion because the lesion was demonstrated as a clear defect only in profile. It became evident that images taken between about 25 and 90 min delineated the myocardium more clearly than those taken in other periods. Normal images taken in 8 patients without ischemic heart disease appeared in the shape of a doughnut of horseshoe, demonstrating mainly the left venticular myocardium. The image was faint in the region of the aortic or mitral valve and thin in the region of the apical wall. A faint image of the right ventricular myocardium was sometimes seen. In 3 patients with valvular heart disease, findings suggested changes in the thickness of myocardium and the distribution of coronary blood flow. In 11 of 12 patients with old myocardial infarction, the location and size of the lesion was detected.

Robust gap repair in the contractile ring ensures timely completion of cytokinesis.

Science.gov (United States)

Silva, Ana M; Osório, Daniel S; Pereira, Antonio J; Maiato, Helder; Pinto, Inês Mendes; Rubinstein, Boris; Gassmann, Reto; Telley, Ivo Andreas; Carvalho, Ana Xavier

2016-12-19

Cytokinesis in animal cells requires the constriction of an actomyosin contractile ring, whose architecture and mechanism remain poorly understood. We use laser microsurgery to explore the biophysical properties of constricting rings in Caenorhabditis elegans embryos. Laser cutting causes rings to snap open. However, instead of disintegrating, ring topology recovers and constriction proceeds. In response to severing, a finite gap forms and is repaired by recruitment of new material in an actin polymerization-dependent manner. An open ring is able to constrict, and rings repair from successive cuts. After gap repair, an increase in constriction velocity allows cytokinesis to complete at the same time as controls. Our analysis demonstrates that tension in the ring increases while net cortical tension at the site of ingression decreases throughout constriction and suggests that cytokinesis is accomplished by contractile modules that assemble and contract autonomously, enabling local repair of the actomyosin network. Consequently, cytokinesis is a highly robust process impervious to discontinuities in contractile ring structure. © 2016 Silva et al.

Myocardial perfusion modeling using MRI

DEFF Research Database (Denmark)

Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

1996-01-01

In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... turbo-FLASH (fast low-angle shot) sequence and Gd-DTPA has been presented. Here, an extension of the model is presented taking into account fast and slow water exchange between the compartments, enabling the calculation of the unidirectional influx constant (Ki) for Gd-DTPA, the distribution volume...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...

A serial changes of thallium-201 myocardial images in a patient with nontransmural myocardial infarction

International Nuclear Information System (INIS)

Tanaka, Takeshi; Itoh, Yukiyoshi; Takayama, Yasuo

1986-01-01

A 66 year old man had suffered from inferior myocardial infarction one year ago and then suffered from effort angina. Recently rest angina attack frequently occurred and he was admitted because of angina attack refractory to TNG. The patient was diagnosed as broad nontransmural infarction. A serial thallium-201 myocardial imagings at rest and thallium-201 lung uptake imagings were performed and some interesting findings were obtained as followings. Myocardial imagings on 3rd day after admission showed no significant deffect, however EF was 34 %. Immediately after severe ischemic attack marked defect was noted at posterolateral region and ECG showed prominent precordial ST depression without accompanying significant ST change in II, III, aVF. On 3rd day after severe attack under hemodynamically and electrocardiographically stable state posterolateral defect improved, though still persisted. EF was 28 %. On 3rd day postop no marked defects were noted in myocardial imagings, so posterolateral defect at rest after severe ischemic attack was proved to be transient defect. In this case thallium-201 lung uptake was not noted before attack. Immediately after severe attack thallium lung uptake increased and maximal uptake was noted at basal zone of lung, however in chest X-P typical butterfly shadow was noted at upper zone of lung. On 3rd day after severe attack hemodynamics improved and butterfly shadow ceased, though thallium lung uptake increased and noted at upper zone of lung. After operation thallium lung uptake improved. (J.P.N.)

Myocardial infarction after dipyridamole-assisted thallium-201 imaging

International Nuclear Information System (INIS)

Biddle, P.; Lanspa, T.J.; Mohiuddin, S.M.; Malesker, M.A.; Hilleman, D.E.

1989-01-01

A 77-year-old woman with suspected coronary artery disease underwent an oral dipyridamole/thallium-201 myocardial imaging study. Approximately 75 minutes after ingestion of dipyridamole 300 mg suspension, the patient developed chest pain, hypotension, nausea, and diaphoresis. An electrocardiogram revealed ST-T wave changes suggestive of inferior ischemia. Appropriate therapeutic measures, including aminophylline and nitroglycerin, were instituted. Delayed thallium images revealed reversible ischemia in the anteroseptal and posterobasal regions with a fixed defect in the inferobasal region. Cardiac enzyme studies were also indicative of acute myocardial injury. The patient subsequently underwent coronary arteriography and four-vessel coronary artery bypass grafting and was discharged without further complication. This report raises concerns about the potential danger of dipyridamole in patients with severe coronary artery stenosis and collateral circulation. Prophylactic aminophylline should be considered in these patients

Retosiban Prevents Stretch-Induced Human Myometrial Contractility and Delays Labor in Cynomolgus Monkeys.

Science.gov (United States)

Aye, Irving L M H; Moraitis, Alexandros A; Stanislaus, Dinesh; Charnock-Jones, D Stephen; Smith, Gordon C S

2018-03-01

Stretch of the myometrium promotes its contractility and is believed to contribute to the control of parturition at term and to the increased risk of preterm birth in multiple pregnancies. To determine the effects of the putative oxytocin receptor (OTR) inverse agonist retosiban on (1) the contractility of human myometrial explants and (2) labor in nonhuman primates. Human myometrial biopsies were obtained at planned term cesarean, and explants were exposed to stretch in the presence and absence of a range of drugs, including retosiban. The in vivo effects of retosiban were determined in cynomolgus monkeys. Prolonged mechanical stretch promoted myometrial extracellular signal-regulated kinase (ERK)1/2 phosphorylation. Moreover, stretch-induced stimulation of myometrial contractility was prevented by ERK1/2 inhibitors. Retosiban (10 nM) prevented stretch-induced stimulation of myometrial contractility and phosphorylation of ERK1/2. Moreover, the inhibitory effect of retosiban on stretch-induced ERK1/2 phosphorylation was prevented by coincubation with a 100-fold excess of a peptide OTR antagonist, atosiban. Compared with vehicle-treated cynomolgus monkeys, treatment with oral retosiban (100 to 150 days of gestational age) reduced the risk of spontaneous delivery (hazard ratio = 0.07, 95% confidence interval 0.01 to 0.60, P = 0.015). The OTR acts as a uterine mechanosensor, whereby stretch increases myometrial contractility through agonist-free activation of the OTR. Retosiban prevents this through inverse agonism of the OTR and, in vivo, reduced the likelihood of spontaneous labor in nonhuman primates. We hypothesize that retosiban may be an effective preventative treatment of preterm birth in high-risk multiple pregnancies, an area of unmet clinical need.

Evolutionarily conserved sites in yeast tropomyosin function in cell polarity, transport and contractile ring formation

Directory of Open Access Journals (Sweden)

Susanne Cranz-Mileva

2015-08-01

Full Text Available Tropomyosin is a coiled-coil protein that binds and regulates actin filaments. The tropomyosin gene in Schizosaccharomyces pombe, cdc8, is required for formation of actin cables, contractile rings, and polar localization of actin patches. The roles of conserved residues were investigated in gene replacement mutants. The work validates an evolution-based approach to identify tropomyosin functions in living cells and sites of potential interactions with other proteins. A cdc8 mutant with near-normal actin affinity affects patch polarization and vacuole fusion, possibly by affecting Myo52p, a class V myosin, function. The presence of labile residual cell attachments suggests a delay in completion of cell division and redistribution of cell patches following cytokinesis. Another mutant with a mild phenotype is synthetic negative with GFP-fimbrin, inferring involvement of the mutated tropomyosin sites in interaction between the two proteins. Proteins that assemble in the contractile ring region before actin do so in a mutant cdc8 strain that cannot assemble condensed actin rings, yet some cells can divide. Of general significance, LifeAct-GFP negatively affects the actin cytoskeleton, indicating caution in its use as a biomarker for actin filaments.

Basal and β-Adrenergic Cardiomyocytes Contractility Dysfunction Induced by Dietary Protein Restriction is Associated with Downregulation of SERCA2a Expression and Disturbance of Endoplasmic Reticulum Ca2+ Regulation in Rats

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Arlete R. Penitente

2014-07-01

Full Text Available Background: The mechanisms responsible for the cardiac dysfunction associated with dietary protein restriction (PR are poorly understood. Thus, this study was designed to evaluate the effects of PR on calcium kinetics, basal and β-adrenergic contractility in murine ventricular cardiomyocytes. Methods: After breastfeeding male Fisher rats were distributed into a control group (CG, n = 20 and a protein-restricted group (PRG, n = 20, receiving isocaloric diets for 35 days containing 15% and 6% protein, respectively. Biometric and hemodynamic variables were measured. After euthanasia left ventricles (LV were collected for histopathological evaluation, SERCA2a expression, cardiomyocytes contractility and Ca2+sparks analysis. Results: PRG animals showed reduced general growth, increased heart rate and arterial pressure. These animals presented extracellular matrix expansion and disorganization, cardiomyocytes hypotrophy, reduced amplitudes of shortening and maximum velocity of contraction and relaxation at baseline and after β-adrenergic stimulation. Reduced SERCA2a expression as well as higher frequency and lower amplitude of Ca2+sparks were observed in PRG cardiomyocytes. Conclusion: The observations reveal that protein restriction induces marked myocardial morphofunctional damage. The pathological changes of cardiomyocyte mechanics suggest the potential involvement of the β-adrenergic system, which is possibly associated with changes in SERCA2a expression and disturbances in Ca2+ intracellular kinetics.

Quantitative analysis of thallium-201 myocardial scintigraphy

International Nuclear Information System (INIS)

Kanemoto, Nariaki; Hoer, G.; Johost, S.; Maul, F.-D.; Standke, R.

1981-01-01

The method of quantitative analysis of thallium-201 myocardial scintigraphy using computer assisted technique was described. Calculated indices are washout factor, vitality index and redistribution factor. Washout factor is the ratio of counts at certain period of time after exercise and immediately after exercise. This value is neccessary for the evaluation of redistribution to the ischemic areas in serial imagings to correct the Tl-201 washout from the myocardium under the assumption that the washout is constant in the whole myocardium. Vitality index is the ratio between the Tl-201 uptake in the region of interest and that of the maximum. Redistribution factor is the ratio of the redistribution in the region of interest in serial imagings after exercise to that of immediately after exercise. Four examples of exercise Tl-201 myocardial scintigrams and the quantitative analyses before and after the percutaneous transluminal coronary angioplasty were presented. (author)

Assessment of myocardial viability by exercise stress myocardial tomography with 201Tl

International Nuclear Information System (INIS)

Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa

1992-01-01

Exercise stress (Ex) and redistribution (RD) myocardial tomography with Tl-201 has been widely used for evaluating myocardial viability. But recent studies have demonstrated that reinjection (ReI) study following RD study is necessary for detecting reversible ischemic myocardium. On the other hand, decreased myocardial washout of Tl-201 after Ex is an indicator of myocardial ischemia. So we have studied the usefulness of myocardial Tl-201 washout rate (WOR) for the evaluation of myocardial viability by comparing it with ReI images. Ex and RD myocardial tomographies were obtained immediately after Ex and 3 hours later. After RD study a small amount of Tl-201 was injected and ReI imaging was repeated. We studied 64 myocardial segments (in 58 patients with coronary artery disease) in which Ex-induced perfusion defects persisted in RD images. According to the changes of perfusion defects between Ex, RD and ReI images, they were classified into 3 types: Type I; perfusion defect on the RD image was identical to ReI image (75%). Type I was divided into 2 subgroups whether perfusion defect at Ex was unchanged (Ia, 42%) or improved (Ib, 33%) on the RD image. Type II; perfusion defect at Ex was reduced on the RD image and it improved furthermore at ReI image (17%). Type III; perfusion defect was the same at Ex and RD but it was reduced on the ReI image (8%). WOR less than 30% was defined as abnormal when Ex heart rate exceeded 120 bpm and lung-myocardial Tl-201 uptake ratio was less than 0.45. The differentiation between Type Ia and Type III is of great importance. History of myocardial infarction, effort angina and Ex induced ST depression could not differentiate these 2 groups. WOR abnormality was observed in all of Type III, but WOR was normal in Type Ia. In conclusion, WOR abnormality in Ex-RD myocardial imaging is useful for evaluating myocardial viability. ReI imaging is necessary for the precise evaluation of viable muscle mass and for inadequate Ex. (author)

Electromechanical wave imaging and electromechanical wave velocity estimation in a large animal model of myocardial infarction

Science.gov (United States)

Costet, Alexandre; Melki, Lea; Sayseng, Vincent; Hamid, Nadira; Nakanishi, Koki; Wan, Elaine; Hahn, Rebecca; Homma, Shunichi; Konofagou, Elisa

2017-12-01

Echocardiography is often used in the clinic for detection and characterization of myocardial infarction. Electromechanical wave imaging (EWI) is a non-invasive ultrasound-based imaging technique based on time-domain incremental motion and strain estimation that can evaluate changes in contractility in the heart. In this study, electromechanical activation is assessed in infarcted heart to determine whether EWI is capable of detecting and monitoring infarct formation. Additionally, methods for estimating electromechanical wave (EW) velocity are presented, and changes in the EW propagation velocity after infarct formation are studied. Five (n  =  5) adult mongrels were used in this study. Successful infarct formation was achieved in three animals by ligation of the left anterior descending (LAD) coronary artery. Dogs were survived for a few days after LAD ligation and monitored daily with EWI. At the end of the survival period, dogs were sacrificed and TTC (tetrazolium chloride) staining confirmed the formation and location of the infarct. In all three dogs, as soon as day 1 EWI was capable of detecting late-activated and non-activated regions, which grew over the next few days. On final day images, the extent of these regions corresponded to the location of infarct as confirmed by staining. EW velocities in border zones of infarct were significantly lower post-infarct formation when compared to baseline, whereas velocities in healthy tissues were not. These results indicate that EWI and EW velocity might help with the detection of infarcts and their border zones, which may be useful for characterizing arrhythmogenic substrate.

201Tl uptake in variant angina: probable demonstration of myocardial reactive hyperemia in man

International Nuclear Information System (INIS)

Kronenberg, M.W.; Robertson, R.M.; Born, M.L.; Steckley, R.A.; Robertson, D.; Friesinger, G.C.

1982-01-01

Myocardial thallium scintigraphy was performed in four subjects with variant angina and in one subject with isolated, fixed coronary obstruction. Three subjects with variant angina had short episodes of ischemic ST-segment elevation that lasted 20--100 seconds. Thallium scintigrams demonstrated excess uptake in regions judged to be ischemic by angiographic and electrocardiographic criteria. Two subjects, one with variant angina and the other with a fixed coronary lesion, had prolonged episodes of ischemia that lasted 390--900 seconds. Both had reduced thallium uptake in the ischemic regions. We conclude that myocardial reactive hyperemia is the cause of excess thallium uptake in patients with variant angina who have short episodes of myocardial ischemia

Identification of acute myocardial infarction with MR imaging by using combined assessment of regional wall motion and Gd-DTPA uptake

International Nuclear Information System (INIS)

Roos, A. de; Matheijssen, N.A.A.; Doornbos, J.; van Dijkman, P.; Pattynama, P.; van der Wall, E.

1990-01-01

This paper evaluates the usefulness of MR imaging for identification of acute myocardial infarction (AMI) in clinical patients, based on the assessment of regional wall motion abnormalities in conjunction with local uptake of Gd-DTPA. Fourteen patients with proved AMI and 12 normal volunteers underwent multisection-multiphase MR imaging in the short-axis plane encompassing the entire left ventricle. Gd-DTPA (0.2 mmol/kg) was injected in all patients to enhance the infarcted region. MR cine loops of the patients and volunteers were blinded and displayed. Three experienced observers scored the cine loops in consensus as to the presence or absence of AMI, noting wall motion abnormalities and/or increased Gd-DTPA uptake

Different Causes of Death in Patients with Myocardial Infarction Type 1, Type 2, and Myocardial Injury.

Science.gov (United States)

Lambrecht, Sascha; Sarkisian, Laura; Saaby, Lotte; Poulsen, Tina S; Gerke, Oke; Hosbond, Susanne; Diederichsen, Axel C P; Thygesen, Kristian; Mickley, Hans

2018-05-01

Data outlining the mortality and the causes of death in patients with type 1 myocardial infarction, type 2 myocardial infarction, and those with myocardial injury are limited. During a 1-year period from January 2010 to January 2011, all hospitalized patients who had cardiac troponin I measured on clinical indication were prospectively studied. Patients with at least one cardiac troponin I value >30 ng/L underwent case ascertainment and individual evaluation by an experienced adjudication committee. Patients were classified as having type 1 myocardial infarction, type 2 myocardial infarction, or myocardial injury according to the criteria of the universal definition of myocardial infarction. Follow-up was ensured until December 31, 2014. Data on mortality and causes of death were obtained from the Danish Civil Registration System and the Danish Register of Causes of Death. Overall, 3762 consecutive patients were followed for a mean of 3.2 years (interquartile range 1.3-3.6 years). All-cause mortality differed significantly among categories: Type 1 myocardial infarction 31.7%, type 2 myocardial infarction 62.2%, myocardial injury 58.7%, and 22.2% in patients with nonelevated troponin values (log-rank test; P causes, vs 42.6% in patients with type 2 myocardial infarction (P = .015) and 41.2% in those with myocardial injury (P causes of death did not differ substantially between patients with type 2 myocardial infarction and those with myocardial injury. Patients with type 2 myocardial infarction and myocardial injury exhibit a significantly higher long-term mortality compared with patients with type 1 myocardial infarction . However, most patients with type 1 myocardial infarction die from cardiovascular causes in contrast to patients with type 2 myocardial infarction and myocardial injury, in whom noncardiovascular causes of death predominate. Copyright © 2018 Elsevier Inc. All rights reserved.

Monitoring of myocardial edema following acute myocardial infarction

International Nuclear Information System (INIS)

Tahir, E.; Sinn, M.; Avanesov, M.; Wien, J.; Saering, D.; Stehning, C.; Radunski, U. K.; Muellerleile, K.; Adam, G.; Lund, G. K.

2015-01-01

Full text: Currently, myocardial edema monitoring after acute myocardial infarction (AMI) is based on visualization of the region with increased signal-intensity on T2-weighted images. Native T1 and T2 mapping are promising novel MRI techniques to quantitatively assess myocardial edema. The purpose of the study was to quantitatively evaluate resorption of myocardial edema following AMI by native T1 and T2 -mapping cardiac magnetic resonance imaging (CMR). CMR (1.5 Tesla Philips Achieva) was performed in 30 patients four times after reperfused AMI at baseline (BL) at 9±6 days after infarction and at 7±1 weeks (follow-up 1, FU1), 3.6±0.5 months (FU2) and 6.5±0.7 months (FU3), respectively. Edema sensitive black-blood T2-weighted (T2w) STIR CMR was performed on end-diastolic LV short-axes. A free-breathing, navigatorgated multi-echo sequence was used for short-axis T2 mapping. T1 mapping was performed using the modified look-locker inversion recovery (MOLLI) sequence. T2 maps were calculated from nine and T1 maps from eight echoes using a dedicated plug-in written for OsiriX software. Two experienced observers independently evaluated T2w-CMR as well as T1 and T2 mapping using the HeAT-Software applying a threshold method. Size of edema and prolongation of the native T1- or T2-time was measured using a cutoff >2SD of remote normal myocardium. Edema size continuously decreased from BL with 32.8 %LV to 24.6 %LV at FU1, to 19.1 %LV at FU2 and to 16.4 %LV at FU3 using T2w-CMR. An almost identical decrease of edema size was observed using native T1 and T2 - mapping. T2 times only decreased between BL from 79±5 ms to 73±2 ms at FU1 (P<0.05), but no further change was observed at later time points with 70±5 ms at FU2 and 70±6 ms at FU3. At all time points the T2 times of remote normal myocardium were about 50±2 ms and significantly lower compared to the edema zone. Also native T1 time within the edema was with 1253 ±103 ms significantly increased compared to remote

Myocardial imaging. Coxsackie myocarditis

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Wells, R.G.; Ruskin, J.A.; Sty, J.R.

1986-09-01

A 3-week-old male neonate with heart failure associated with Coxsackie virus infection was imaged with Tc-99m PYP and TI-201. The abnormal imaging pattern suggested myocardial infarction. Autopsy findings indicated that the cause was myocardial necrosis secondary to an acute inflammatory process. Causes of abnormal myocardial uptake of Tc-99m PYP in pediatrics include infarction, myocarditis, cardiomyopathy, bacterial endocarditis, and trauma. Myocardial imaging cannot provide a specific cause diagnosis. Causes of myocardial infarction in pediatrics are listed in Table 1.

Myocardial imaging. Coxsackie myocarditis

International Nuclear Information System (INIS)

Wells, R.G.; Ruskin, J.A.; Sty, J.R.

1986-01-01

A 3-week-old male neonate with heart failure associated with Coxsackie virus infection was imaged with Tc-99m PYP and TI-201. The abnormal imaging pattern suggested myocardial infarction. Autopsy findings indicated that the cause was myocardial necrosis secondary to an acute inflammatory process. Causes of abnormal myocardial uptake of Tc-99m PYP in pediatrics include infarction, myocarditis, cardiomyopathy, bacterial endocarditis, and trauma. Myocardial imaging cannot provide a specific cause diagnosis. Causes of myocardial infarction in pediatrics are listed in Table 1

The Functional Lumen Imaging Probe Detects Esophageal Contractility Not Observed With Manometry in Patients With Achalasia.

Science.gov (United States)

Carlson, Dustin A; Lin, Zhiyue; Kahrilas, Peter J; Sternbach, Joel; Donnan, Erica N; Friesen, Laurel; Listernick, Zoe; Mogni, Benjamin; Pandolfino, John E

2015-12-01

The functional lumen imaging probe (FLIP) could improve the characterization of achalasia subtypes by detecting nonocclusive esophageal contractions not observed with standard manometry. We aimed to evaluate esophageal contractions during volumetric distention in patients with achalasia using FLIP topography. Fifty-one treatment-naive patients with achalasia, defined and subclassified by high-resolution esophageal pressure topography, and 10 asymptomatic individuals (controls) were evaluated with the FLIP during endoscopy. During stepwise distension, simultaneous intrabag pressures and 16 channels of cross-sectional areas were measured; data were exported to software that generated FLIP topography plots. Esophageal contractility was identified by noting periods of reduced luminal diameter. Esophageal contractions were characterized further by propagation direction, repetitiveness, and based on whether they were occluding or nonoccluding. Esophageal contractility was detected in all 10 controls: 8 of 10 had repetitive antegrade contractions and 9 of 10 had occluding contractions. Contractility was detected in 27% (4 of 15) of patients with type I achalasia and in 65% (18 of 26, including 9 with occluding contractions) of patients with type II achalasia. Contractility was detected in all 10 patients with type III achalasia; 8 of these patients had a pattern of contractility that was not observed in controls (repetitive retrograde contractions). Esophageal contractility not observed with manometry can be detected in patients with achalasia using FLIP topography. The presence and patterns of contractility detected with FLIP topography may represent variations in pathophysiology, such as mechanisms of panesophageal pressurization in patients with type II achalasia. These findings could have implications for additional subclassification to supplement prediction of the achalasia disease course. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights

Study progress of cardiac MRI technology in assessment of myocardial viability after myocardial infarction

International Nuclear Information System (INIS)

Wang Jing; Zhang Hao

2013-01-01

Acute myocardial infarction (AMI) is one of the most common diseases that cause disability and death around the world. Correctly and effectively assessing the myocardial viability after myocardial infarction can reduce the disabled rate and mortality rate. At present, many methods could be used to assess myocardial viability. The cardiac magnetic resonance imaging (CMR) technology has a lot of advantages compared to other methods. In this paper, we reviewed the research progress of CMR in assessment of myocardial viability after myocardial infarction, and compared CMR with other technologies. (authors)

The diagnosis of silent myocardial ischemia. Motion-Frozen (or morphing) myocardial perfusion imaging.

Science.gov (United States)

Chang, Cheng; Ye, Bo; Xie, Wenhui; Zhang, Daoliang; Lei, Bei; Ye, Xiaodan

2016-01-01

Silent myocardial ischemia is typically defined as objective evidence of myocardial ischemia in patients without subjective ischemia symptoms. Currently, coronary artery angiography is the gold standard for diagnosis of asymptomatic coronary artery disease (CAD). Computed tomography coronary angiography (CTCA) can visually demonstrate the morphology, trend and extent of coronary stenosis and is commonly used in clinical screening of CAD. Myocardial perfusion imaging can be used not only to identify whether anatomical stenosis causes myocardial dysfunction, but to also assess the risk stratification and prognosis of myocardial disease (MD). Myocardial perfusion imaging using morphing combined with CTCA can simultaneously show the relationship between CAD and myocardial ischemia from an anatomical and functional aspect. This allows earlier diagnosis of asymptomatic CAD myocardial ischemia, accurate identification of the culprit vessels, and could prevent unnecessary interventional therapy. The 1-day dobutamine stress/resting met-hod is also one of the methods used. The combination of CTCA and the morphing technique can provide anatomical and functional information on coronary arteries at the same time, significantly improving the diagnostic sensitivity, specificity, and accuracy of MD.

Clinical evaluation of the Tl-201 ECG-gated myocardial SPECT

International Nuclear Information System (INIS)

Mochizuki, Teruhito

1989-01-01

In order to evaluate the clinical usefulness of the Tl-201 ECG-gated myocardial single photon emission computed tomography (SPECT), we compared the wall motion and the grade of the Tl-201 uptake of the ECG-gated myocardial SPECT with the wall motion of the ECG-gated blood pool SPECT. Materials were 87 patients of 50 old myocardial infarctions (OMIs), 19 hypertrophic cardiomyopathies (HCMs), 2 dilated cardiomyopathies (DCMs) and 16 others. After intravenous injection of 111-185 MBq (3-5 mCi) of Tl-201 at rest, the projection data were acquired using a rotating gamma-camera through 180deg, from RAO 45deg in 24 directions, each of which consisted of 80-100 beats. For the reconstruction of ED, ES and non-gated images, R-R interval was divided into about 20 (18-22) fractions. In 348 regions of interest (anterior, septal, lateral and inferior wall) in 87 cases, wall motion and the Tl-201 uptake were evaluated to three grades (normal, hypokinesis and akinesis; normal, low and defect, respectively), which were compared with the wall motion of the ECG-gated blood pool SPECT. The wall motion and the grade of the Tl-201 uptake of the ECG-gated myocardial SPECT correlated well with the wall motion of the ECG-gated blood pool SPECT (96.6% and 87.9%, respectively). In conclusion, the ECG-gated myocardial SPECT can provide clear perfusion images and is a very useful diagnostic strategy to evaluate the regional wall motion and perfusion simultaneously. (author)

Screening for silent myocardial ischemia caseof diabetics : interest of myocardial perfusion scintigraphy

International Nuclear Information System (INIS)

Bahri, Haifa

2007-01-01

Silent myocardial ischemia is a major cause of morbidity and mortality in diabetic patients. Its diagnosis by noninvasive means such as myocardial SPECT would improve the management of these patients. The purpose of this study is to assess the frequency of silent myocardial ischemia in asymptomatic diabetics and their evolution. As a result, the myocardial SPECT is a reliable tool for screening for silent myocardial ischemia in diabetic patients. Its prognostic value allows to stratify the cardiac risk and guide therapeutic management. Its integration into a screening strategy in Tunisia seems limited by its low availability and cost. The latter could be reduced by better patient selection.

Periodontitis and myocardial hypertrophy.

Science.gov (United States)

Suzuki, Jun-Ichi; Sato, Hiroki; Kaneko, Makoto; Yoshida, Asuka; Aoyama, Norio; Akimoto, Shouta; Wakayama, Kouji; Kumagai, Hidetoshi; Ikeda, Yuichi; Akazawa, Hiroshi; Izumi, Yuichi; Isobe, Mitsuaki; Komuro, Issei

2017-04-01

There is a deep relationship between cardiovascular disease and periodontitis. It has been reported that myocardial hypertrophy may be affected by periodontitis in clinical settings. Although these clinical observations had some study limitations, they strongly suggest a direct association between severity of periodontitis and left ventricular hypertrophy. However, the detailed mechanisms between myocardial hypertrophy and periodontitis have not yet been elucidated. Recently, we demonstrated that periodontal bacteria infection is closely related to myocardial hypertrophy. In murine transverse aortic constriction models, a periodontal pathogen, Aggregatibacter actinomycetemcomitans markedly enhanced cardiac hypertrophy with matrix metalloproteinase-2 activation, while another pathogen Porphyromonas gingivalis (P.g.) did not accelerate these pathological changes. In the isoproterenol-induced myocardial hypertrophy model, P.g. induced myocardial hypertrophy through Toll-like receptor-2 signaling. From our results and other reports, regulation of chronic inflammation induced by periodontitis may have a key role in the treatment of myocardial hypertrophy. In this article, we review the pathophysiological mechanism between myocardial hypertrophy and periodontitis.

Dobutamine cardiovascular magnetic resonance for the detection of myocardial ischemia with the use of myocardial tagging.

Science.gov (United States)

Kuijpers, Dirkjan; Ho, Kai Yiu J A M; van Dijkman, Paul R M; Vliegenthart, Rozemarijn; Oudkerk, Matthijs

2003-04-01

The purpose of this study was to assess the value of high-dose dobutamine cardiovascular magnetic resonance (CMR) with myocardial tagging for the detection of wall motion abnormalities as a measure of myocardial ischemia in patients with known or suspected coronary artery disease. Two hundred eleven consecutive patients with chest pain underwent dobutamine-CMR 4 days after antianginal medication was stopped. Dobutamine-CMR was performed at rest and during increasing doses of dobutamine. Cine-images were acquired during breath-hold with and without myocardial tagging at 3 short-axis levels. Regional wall motion was assessed in a 16-segment short-axis model. Patients with new wall motion abnormalities (NWMA) were examined by coronary angiography. Dobutamine-CMR was successfully performed in 194 patients. Dobutamine-CMR without tagging detected NWMA in 58 patients, whereas NWMA were detected in 68 patients with tagging (P=0.002, McNemar). Coronary angiography showed coronary artery disease in 65 (96%) of these 68 patients. All but 3 of the 65 patients needed revascularization. In the 112 patients with a negative dobutamine-CMR study, without baseline wall motion abnormalities, the cardiovascular occurrence-free survival rate was 98.2% during the mean follow-up period of 17.3 months (range, 7 to 31). Dobutamine-CMR with myocardial tagging detected more NWMA compared with dobutamine-CMR without tagging and reliably separated patients with a normal life expectancy from those at increased risk of major adverse cardiac events.

Three-dimensional transesophageal echocardiography: Principles and clinical applications

Directory of Open Access Journals (Sweden)

Annette Vegas

2016-01-01

Full Text Available A basic understanding of evolving 3D technology enables the echocardiographer to master the new skills necessary to acquire, manipulate, and interpret 3D datasets. Single button activation of specific 3D imaging modes for both TEE and transthoracic echocardiography (TTE matrix array probes include (a live, (b zoom, (c full volume (FV, and (d color Doppler FV. Evaluation of regional LV wall motion by RT 3D TEE is based on a change in LV chamber subvolume over time from altered segmental myocardial contractility. Unlike standard 2D TEE, there is no direct measurement of myocardial thickening or displacement of individual segments.

Plasticity of TOM complex assembly in skeletal muscle mitochondria in response to chronic contractile activity.

Science.gov (United States)

Joseph, Anna-Maria; Hood, David A

2012-03-01

We investigated the assembly of the TOM complex within skeletal muscle under conditions of chronic contractile activity-induced mitochondrial biogenesis. Tom40 import into mitochondria was increased by chronic contractile activity, as was its time-dependent assembly into the TOM complex. These changes coincided with contractile activity-induced augmentations in the expression of key protein import machinery components Tim17, Tim23, and Tom22, as well as the cytosolic chaperone Hsp90. These data indicate the adaptability of the TOM protein import complex and suggest a regulatory role for the assembly of this complex in exercise-induced mitochondrial biogenesis. Copyright © 2011 Elsevier B.V. and Mitochondria Research Society. All rights reserved. All rights reserved.

Overexpression of the human angiotensin II type 1 receptor in the rat heart augments load induced cardiac hypertrophy

NARCIS (Netherlands)

Hoffmann, S.; Krause, T.; van Geel, P. P.; Willenbrock, R.; Pagel, I.; Pinto, Y. M.; Buikema, H.; van Gilst, W. H.; Lindschau, C.; Paul, M.; Inagami, T.; Ganten, D.; Urata, H.

2001-01-01

Angiotensin II is known to stimulate cardiac hypertrophy and contractility. Most angiotensin II effects are mediated via membrane bound AT1 receptors. However, the role of myocardial AT1 receptors in cardiac hypertrophy and contractility is still rarely defined. To address the hypothesis that

Overexpression of the human angiotensin II type 1 receptor in the rat heart augments load induced cardiac hypertrophy

NARCIS (Netherlands)

Hoffmann, S; van Geel, PP; Willenbrock, R; Pagel, [No Value; Pinto, YM; Buikema, H; van Gilst, WH; Lindschau, C; Paul, M; Inagami, T; Ganten, D; Urata, H

2001-01-01

Angiotensin II is known to stimulate cardiac hypertrophy and contractility. Most angiotensin II effects are mediated via membrane bound AT(1) receptors. However, the role of myocardial AT(1) receptors in cardiac hypertrophy and contractility is still rarely defined. To address the hypothesis that

Transient impairments in single muscle fibre contractile function after prolonged cycling in elite endurance athletes

DEFF Research Database (Denmark)

Hvid, L G; Gejl, Kasper Degn; Bech, R D

2013-01-01

Prolonged muscle activity impairs whole-muscle performance and function. However, little is known about the effects of prolonged muscle activity on the contractile function of human single muscle fibres. The purpose of this study was to investigate the effects of prolonged exercise and subsequent...... recovery on the contractile function of single muscle fibres obtained from elite athletes....

Angiographically demonstrated coronary collaterals predict residual viable myocardium in patients with chronic myocardial infarction. A regional metabolic study

International Nuclear Information System (INIS)

Fukai, Masumi; Ii, Masaaki; Nakakoji, Takahiro

2000-01-01

Angiographical demonstration of coronary collateral circulation may suggest the presence of residual viable myocardium. The development of coronary collaterals was judged according to Rentrop's classification in 37 patients with old anteroseptal myocardial infarction and 13 control patients with chest pain syndrome. The subjects with myocardial infarction were divided into 2 groups: 17 patients with the main branch of the left coronary artery clearly identified by collateral blood flow from the contralateral coronary artery [Coll (+) group, male/female 10/7, mean age 56.6 years] and 20 patients with obscure coronary trunk [Coll (-) group, male/female 16/4, mean age 54.9 years]. Thallium-201 myocardial scintigraphy and examination of local myocardial metabolism were carried out by measuring the flux of lactic acid under dipyridamole infusion load. Coronary stenosis of 99% or total occlusion was found in only 5 of 20 patients (25%) in the Coll (-) group but in 16 of 17 patients (94%) in the Coll (+) group (p<0.001). Redistribution of myocardial scintigraphy was found in 11 of 15 patients (73%) in the Coll (+) group, but only 3 of 18 patients (17%) in the Coll (-) group (p<0.01). The myocardial lactic acid extraction rate was -13.2±17.0% in the Coll (+) group, but 9.1±13.2% in the Coll (-) group (p<0.001). These results suggest that coronary collateral may contribute to minimizing the infarct area and to prediction of the presence of viable myocardium. (author)

The clinical application value of myocardial perfusion imaging in evaluating coronary artery myocardial bridge patients with symptoms

International Nuclear Information System (INIS)

Wang Yuetao; Fu Ning; Ding Xuemei; Lu Cunzhi; Zhu Feng; Wang Guanmin; Huang Yijie; Wang Linguang

2008-01-01

Objective: Myocardial bridge is a common inborn coronary artery anomaly, myocardial bridge may be associated with myocardial ischemia. Only a few patients with coronary artery myocardial bridge were evaluated with nuclear medicine techniques. The aim of this study was to investigate the role of nuclear cardiology with myocardial perfusion technique in symptomatic myocardial bridge patients. Methods Nineteen myocardial bridge patients with the symptoms of chest pain and chest distress were analyzed retrospectively. 99 Tc m -methoxyisobutylisonitrile (MIBI) myocardial perfusion images (both exercise and rest) were performed in all. Imaging results were compared with the results of movement electrocardiogram (ECG) and coronary arteriography. The t test or χ 2 test was used to statistically analyze the data with Stata 7.0 software. Results: Of the 19 patients, 18 patients had myocardial bridge locating at the left anterior descending artery, 1 patient at the left anterior descending and left circumflex artery, the mean angiographic systolic occlusion within the myocardial bridge was (65.4 ± 22.1)%. Of these 19 patients, Exercise-rest 99 Tc m -MIBI myocardial perfusion imaging defined positive myocardial ischemia in 10 and negative in 9 patients. Of the 10 patients with 99 Tc m -MIBI myocardial perfusion imaging defined myocardial ischemia, 8 had reversible radioactive defect of partial anterior wall and (or) apex, 1 had reversible defect of post lateral wall and post septal wall, and 1 had reversible defect of inferior wall. The positive predictive value of myocardial perfusion imaging was 52.6% (10/19), which was higher than movement ECG [21.1% (4/19), χ 2 = 4.07, P 99 Tc m -MIBI myocardial periusion imaging defined myocardial ischemia. Six cases with Grade II stenosis, two were 99 Tc m -MIBI myocardial perfusion imaging defined myocardial ischemia. Eight cases with Grade III stenosis, seven were 99 Tc m -MIBI myocardial perfusion imaging defined myocardial

Intravenous Administration of Lycopene, a Tomato Extract, Protects against Myocardial Ischemia-Reperfusion Injury.

Science.gov (United States)

Tong, Chao; Peng, Chuan; Wang, Lianlian; Zhang, Li; Yang, Xiaotao; Xu, Ping; Li, Jinjin; Delplancke, Thibaut; Zhang, Hua; Qi, Hongbo

2016-03-03

Oral uptake of lycopene has been shown to be beneficial for preventing myocardial ischemia-reperfusion (I/R) injury. However, the strong first-pass metabolism of lycopene influences its bioavailability and impedes its clinic application. In this study, we determined an intravenous (IV) administration dose of lycopene protects against myocardial infarction (MI) in a mouse model, and investigated the effects of acute lycopene administration on reactive oxygen species (ROS) production and related signaling pathways during myocardial I/R. In this study, we established both in vitro hypoxia/reoxygenation (H/R) cell model and in vivo regional myocardial I/R mouse model by ligating left anterior artery descending. TTC dual staining was used to assess I/R induced MI in the absence and presence of acute lycopene administration via tail vein injection. Lycopene treatment (1 μM) before reoxygenation significantly reduced cardiomyocyte death induced by H/R. Intravenous administration of lycopene to achieve 1 μM concentration in circulating blood significantly suppressed MI, ROS production, and JNK phosphorylation in the cardiac tissue of mice during in vivo regional I/R. Elevating circulating lycopene to 1 μM via IV injection protects against myocardial I/R injury through inhibition of ROS accumulation and consequent inflammation in mice.

Effects of endothelin, calcium channel blockade and EDRF inhibition on the contractility of human uteroplacental arteries.

Science.gov (United States)

Fried, G; Liu, Y A

1994-08-01

In order to examine the possibility that endothelin might be important in the regulation of placental blood flow, human uteroplacental vessels were superfused in vitro to study the contractile effect of endothelin as compared with a known strong contractor of placental blood vessels, serotonin (5-HT). The contractile responses were compared in the presence and absence of calcium channel blocking agents, as well as in the presence of L-NMA, an inhibitor of EDRF/nitric oxide. Endothelin (ET, 10(-10)-10(-6) M) and 5-HT (10(-8)-10(-4) M) induced contractions in the vessels. Maximal contractions in the presence of endothelin were elicited at 10(-7) M, whereas 5-HT elicited maximal contractions at 10(-5) M. At 10(-7) M, ET was more potent than 5-HT. The calcium-channel blocking agents nifedipine, diltiazem and NiCl2 relaxed the vessels by 5-15% from baseline. The contractile response to ET in the presence of nifedipine or diltiazem was reduced by 55 and 67%, respectively. The response of 5-HT in the presence of nifedipine was reduced by 58%. The contractile response to 5-HT as well as ET in the presence of both nifedipine and NiCl2 was not significantly lower than in the presence of nifedipine only. The EDRF-inhibiting agent L-NMA caused a small contractile response at concentrations of 10(-6)-10(-5) M. ET as well as 5-HT added after pretreatment with L-NMA produced a larger contractile response than ET or 5-HT alone. The results show that ET has a strong contractile effect on placental blood vessels at concentrations likely to occur during labor and delivery. The mechanism whereby ET as well as 5-HT contracts placental vessel smooth muscle appears to partly involve nifedipine- and diltiazem-sensitive calcium channels, but almost half of the response depends on mobilization of calcium through other means.

Continuous determination of regional myocardial blood flow with intracoronary krypton-81m in coronary artery disease

International Nuclear Information System (INIS)

Remme, W.J.; Krauss, X.H.; van Hoogenhuyze, D.C.; Cox, P.H.; Storm, C.J.; Kruyssen, D.A.

1985-01-01

Pacing-induced changes in regional coronary flow were studied continuously with krypton-81m by intracoronary infusion in 25 patients: 21 with 50% or greater diameter narrowing of 1 or more left coronary arteries (group I) and 4 with less than 50% diameter reduction of a left coronary artery (group II). No changes occurred in group II. In group I, krypton-81m perfusion decreased progressively in all areas with more than 70% diameter narrowing, with a simultaneous increase in normal regions. At the end of pacing during angina, krypton-81m perfusion was reduced to 81 +/- 4% of control in areas with 71 to 90% diameter reduction (n = 8) and to 69 +/- 6% in areas with more than 90% diameter narrowing (n = 15). In contrast, in regions with 50 to 70% diameter reduction changes were variable (decrease in 4 regions, increase in 2 and an unchanged distribution in 1 region). Krypton-81m perfusion decreased early, before general signs of ischemia in areas with more than 90% diameter reduction, whereas this decrease occurred later in regions with 71 to 90% diameter narrowing, concurrently with ST-segment changes but before anginal pain. Although all signs of ischemia had disappeared between 2 and 5 minutes after pacing, changes in krypton-81m distribution persisted in most areas for 5 to 15 minutes after pacing. It is concluded that the functional significance of coronary arterial narrowing can be assessed with a continuous intracoronary infusion of krypton-81m. Changes in regional distribution persisted after cessation of pacing-induced ischemia, indicating an ongoing decrease in regional myocardial blood flow

Evaluation of the differences of myocardial fibers between acute and chronic myocardial infarction: Application of diffusion tensor magnetic resonance imaging INA Rhesus monkey model

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Wang, Yu Qing; Cai, Wei; Wang, Lei; Xia, Rui; Chen, Wei; Zheng, Jie [Dept. of Radiology, West China Hospital, Sichuan University, Sichuan (China); Gao, Fabao [Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis (United States)

2016-09-15

To understand microstructural changes after myocardial infarction (MI), we evaluated myocardial fibers of rhesus monkeys during acute or chronic MI, and identified the differences of myocardial fibers between acute and chronic MI. Six fixed hearts of rhesus monkeys with left anterior descending coronary artery ligation for 1 hour or 84 days were scanned by diffusion tensor magnetic resonance imaging (MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). Comparing with acute MI monkeys (FA: 0.59 ± 0.02; ADC: 5.0 ± 0.6 × 10{sup -4} mm{sup 2}/s; HA: 94.5 ± 4.4°), chronic MI monkeys showed remarkably decreased FA value (0.26 ± 0.03), increased ADC value (7.8 ± 0.8 × 10{sup -4} mm{sup 2}/s), decreased HA transmural range (49.5 ± 4.6°) and serious defects on endocardium in infarcted regions. The HA in infarcted regions shifted to more components of negative left-handed helix in chronic MI monkeys (-38.3 ± 5.0°–11.2 ± 4.3°) than in acute MI monkeys (-41.4 ± 5.1°–53.1 ± 3.7°), but the HA in remote regions shifted to more components of positive right-handed helix in chronic MI monkeys (-43.8 ± 2.7°–66.5 ± 4.9°) than in acute MI monkeys (-59.5 ± 3.4°–64.9 ± 4.3°). Diffusion tensor MRI method helps to quantify differences of mechanical microstructure and water diffusion of myocardial fibers between acute and chronic MI monkey's models.

Evaluation of the differences of myocardial fibers between acute and chronic myocardial infarction: Application of diffusion tensor magnetic resonance imaging INA Rhesus monkey model

International Nuclear Information System (INIS)

Wang, Yu Qing; Cai, Wei; Wang, Lei; Xia, Rui; Chen, Wei; Zheng, Jie; Gao, Fabao

2016-01-01

To understand microstructural changes after myocardial infarction (MI), we evaluated myocardial fibers of rhesus monkeys during acute or chronic MI, and identified the differences of myocardial fibers between acute and chronic MI. Six fixed hearts of rhesus monkeys with left anterior descending coronary artery ligation for 1 hour or 84 days were scanned by diffusion tensor magnetic resonance imaging (MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). Comparing with acute MI monkeys (FA: 0.59 ± 0.02; ADC: 5.0 ± 0.6 × 10 -4 mm 2 /s; HA: 94.5 ± 4.4°), chronic MI monkeys showed remarkably decreased FA value (0.26 ± 0.03), increased ADC value (7.8 ± 0.8 × 10 -4 mm 2 /s), decreased HA transmural range (49.5 ± 4.6°) and serious defects on endocardium in infarcted regions. The HA in infarcted regions shifted to more components of negative left-handed helix in chronic MI monkeys (-38.3 ± 5.0°–11.2 ± 4.3°) than in acute MI monkeys (-41.4 ± 5.1°–53.1 ± 3.7°), but the HA in remote regions shifted to more components of positive right-handed helix in chronic MI monkeys (-43.8 ± 2.7°–66.5 ± 4.9°) than in acute MI monkeys (-59.5 ± 3.4°–64.9 ± 4.3°). Diffusion tensor MRI method helps to quantify differences of mechanical microstructure and water diffusion of myocardial fibers between acute and chronic MI monkey's models

Nitrendipine binding in congestive heart failure due to myocardial infarction

International Nuclear Information System (INIS)

Dixon, I.M.; Lee, S.L.; Dhalla, N.S.

1990-01-01

Depressed cardiac pump function is the hallmark of congestive heart failure, and it is suspected that decreased influx of Ca2+ into the cardiac cell is responsible for depressed contractile function. Since Ca2+ channels in the sarcolemmal membrane are considered to be an important route for the entry of Ca2+, we examined the status of Ca2+ receptors/channels in failing rat hearts after myocardial infarction of the left ventricular free wall. For this purpose, the left coronary artery was ligated and hearts were examined 4, 8, and 16 weeks later; sham-operated animals served as controls. Hemodynamic assessment revealed decreased total mechanical energy (left ventricular systolic pressure x heart rate), increased left ventricular diastolic pressure, and decreased positive and negative dP/dt in experimental animals at 4, 8, and 16 weeks. Although accumulation of ascites in the abdominal cavity was evident at 4 weeks, other clinical signs of congestive heart failure in experimental rats were evident from the presence of lung congestion and cardiac dilatation at 8 and 16 weeks after induction of myocardial infarction. The density of Ca2+ receptors/channels in crude membranes, as assessed by [3H]nitrendipine binding assay, was found to be decreased in the uninfarcted experimental left ventricle at 8 and 16 weeks; however, no change in the affinity of nitrendipine was evident. A similar depression in the specific binding of another dihydropyridine compound, [3H]PN200-110, was also evident in failing hearts. Brain and skeletal muscle crude membrane preparations, unlike those of the right ventricle and liver, revealed a decrease in Ca2+ receptors/channels density in experimental animals at 16 weeks

Is myocardial fatty acid metabolism different between hypertrophic cardiomyopathy and hypertensive hypertrophy?

International Nuclear Information System (INIS)

Narita, Michihiro; Kurihara, Tadashi; Usami, Masahisa; Honda, Minoru

1994-01-01

To investigate characteristics of fatty acid metabolism in hypertrophic cardiomyopathy (HCM), we performed myocardial imaging with 123 I-iodophenyl-3-methylpentadecanoic acid (BMIPP) in 24 HCM patients, 13 patients with hypertensive hypertrophy (HT) and 10 normal subjects. Rest myocardial imaging with 123 I-BMIPP was obtained at 20 minutes and 3 hours after 123 I-BMIPP injection. Rest 201 Tl imaging was also performed. In addition to ordinary tomography, whole body imaging was performed to calculate %Uptake (percentage of cardiac uptake of the isotope to total injected dose). As global indexes of fatty acid metabolism, we calculated two parameters; Uptake Ratio (%Uptake of 123 I-BMIPP normalized by myocardial perfusion) and WOR (percent reduction of myocardial 123 I-BMIPP within 3 hours). Regional abnormality was evaluated by visual assessment of ordinary tomograms and by BMIPP/Tl map. BMIPP/Tl map was made from Bull's-eye maps of 123 I-BMIPP and 201 Tl, and it represented 123 I-BMIPP uptake normalized by myocardial perfusion of each pixel which constructed the image. %Uptake of 123 I-BMIPP was not different among three groups. Uptake Ratio was significantly (p HT (1.03±0.08)>HCM (0.87±0.09). WOR of 123 I-BMIPP was accerelated in HCM (12.7±4.7%) and HT (10.2±2.9%) compared with normal (5.1±3.1%) (p 123 I-BMIPP distribution was found in 17 of 24 patients (71%) including 3 patients with equivocal abnormality. In HT patients, only equivocal abnormality was observed in 23%. In BMIPP/Tl map, abnormality was observed in 92% of HCM and 8% of HT. Although global myocardial fatty acid metabolism was equally disturbed both in HCM and HT, regional abnormality of fatty acid metabolism was observed preferetially in HCM. This indicated myocardial fatty acid metabolism was not identical between HCM and HT. (author)

Myocardial perfusion imaging by digital subtraction angiography

International Nuclear Information System (INIS)

Kadowaki, Hiroyuki; Ishikawa, Kinji; Ogai, Toshihiro; Katori, Ryo

1986-01-01

Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; 1) at the R wave of the electrocardiogram, 2) 100 msec before the R wave, and 3) 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery. In all patients with anterior myocardial infarction, low perfusion was observed at the infarcted portion compared to the non-infarcted myocardium. In patients with inferior myocardial infarction, this low perfusion area was not observed because right coronary angiography was not subjected to DSA in this study. (J.P.N.)

Clinical Characteristics and Outcomes of Patients with Myocardial Infarction, Myocardial Injury, and Nonelevated Troponins

DEFF Research Database (Denmark)

Sarkisian, Laura; Saaby, Lotte; Poulsen, Tina S

2016-01-01

BACKGROUND: Cardiac troponins have emerged as the preferred biomarkers for detecting myocardial necrosis and diagnosing myocardial infarction. However, current cardiac troponin assays do not discriminate between ischemic and nonischemic causes of myocardial cell death. Thus, when an increased...... troponin value is encountered in the absence of obvious myocardial ischemia, a careful search for other clinical conditions is crucial. METHODS: In 2010 to 2011, we prospectively studied hospitalized patients who had cardiac troponin I measured on clinical indication. An acute myocardial infarction...... was diagnosed in cases of a cardiac troponin I increase or decrease pattern with at least 1 value >30 ng/L (99th percentile) together with myocardial ischemia. Myocardial injury was defined as cardiac troponin I values >30 ng/L, but without signs or symptoms indicating overt cardiac ischemia. Patients with peak...

A human in vitro model of Duchenne muscular dystrophy muscle formation and contractility.

Science.gov (United States)

Nesmith, Alexander P; Wagner, Matthew A; Pasqualini, Francesco S; O'Connor, Blakely B; Pincus, Mark J; August, Paul R; Parker, Kevin Kit

2016-10-10

Tongue weakness, like all weakness in Duchenne muscular dystrophy (DMD), occurs as a result of contraction-induced muscle damage and deficient muscular repair. Although membrane fragility is known to potentiate injury in DMD, whether muscle stem cells are implicated in deficient muscular repair remains unclear. We hypothesized that DMD myoblasts are less sensitive to cues in the extracellular matrix designed to potentiate structure-function relationships of healthy muscle. To test this hypothesis, we drew inspiration from the tongue and engineered contractile human muscle tissues on thin films. On this platform, DMD myoblasts formed fewer and smaller myotubes and exhibited impaired polarization of the cell nucleus and contractile cytoskeleton when compared with healthy cells. These structural aberrations were reflected in their functional behavior, as engineered tongues from DMD myoblasts failed to achieve the same contractile strength as healthy tongue structures. These data suggest that dystrophic muscle may fail to organize with respect to extracellular cues necessary to potentiate adaptive growth and remodeling. © 2016 Nesmith et al.

DISFUNCIÓN DIASTÓLICA EN EL INFARTO AGUDO DE MIOCARDIO / Diastolic dysfunction in acute myocardial infarction

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Norge Ramón Lara Pérez

2010-03-01

Full Text Available Introduction and objectives: Ischemic heart disease is among the first causes of disability and death in the world. The acute myocardial infarction alters considerably the myocardial relaxation. The echocardiogram is a useful, economic and harmless method to assess diastolic function in these patients; that is why the aim of the study was to characterize the behavior of this left ventricular function by means of an echocardiography. Methods: an observational descriptive study was carried out with 91 patients with myocardial infarction who were hospitalized at the Cardiology Ward of the Arnaldo Milian Castro Provincial University Hospital in Santa Clara during 2008. An echocardiogram was performed between the fifth and the seventh day of evolution, and the patterns of diastolic function were compared with other variables. Results: There was a prevalence of the male sex (74,7 %, the infarctions without ST segment elevation were more frequent (83,1 % – which showed a bigger alteration of the relaxation, much more when the anterior and lateral walls of the left ventricle were involved. The presence of complications was linked to a bigger alteration of the relaxation, and the most associate ones were the contractile dysfunction and malignant arrhythmias. The decrease of the ejection fraction was linked to (p = 0,000 the prolongation of the relaxation. Conclusions: There was a prevalence of the infarction without ST segment elevation. It was more frequent in the male sex and it was associated with a higher level of alteration of the relaxation. The infarctions with anterior or lateral location, and those which caused complications, presented a higher level of this alteration. All patients with a reduced ejection fraction had relaxation disorders.

Global and regional left ventricular function and tomographic radionuclide perfusion: the Western Washington Intracoronary Streptokinase In Myocardial Infarction Trial

International Nuclear Information System (INIS)

Ritchie, J.L.; Davis, K.B.; Williams, D.L.; Caldwell, J.; Kennedy, J.W.

1984-01-01

The Western Washington Intracoronary Streptokinase In Myocardial Infarction Trial enrolled 250 patients with acute myocardial infarction. After the coronary angiographic diagnosis of thrombosis, patients were randomly assigned to receive either conventional therapy with heparin or intracoronary streptokinase followed by heparin. Of the 232 patients who survived at least 60 days, 207 (89%) underwent radionuclide ventriculographic determination of global and regional ejection fraction at a single institution at 62 +/- 35 days after infarction. In the first 100 patients, infarct size was also determined by quantitative single-photon emission tomographic imaging with thallium-201 ( 201 Tl) and expressed as a percentage of the left ventricle with a perfusion defect. Overall, global ejection fraction did not differ between patients treated with streptokinase (45.9 +/- 13.9%; n . 115) and control patients (46.1 +/- 14.4%; n . 92, p . NS). Similarly, the regional posterolateral, inferior, and anteroseptal ejection fraction did not differ between the two groups. Infarct size as measured by 201 Tl tomography was 19.4 +/- 12.8% (n . 52) of the left ventricle for the streptokinase group and 19.6 +/- 11.8% (n . 48; p . NS) for the control group. When patients were compared within groups by electrocardiographic location of infarction, time to treatment, or the presence or absence of vessel opening, there were no significant differences between streptokinase and control patients. Statistical inclusion of the 18 patients who died early and were unavailable for study also failed to modify the results, except for a possible reduction in inferior infarct size as measured by 201 Tl tomography

Clinical evaluation of 123I-BMIPP myocardial scintigraphy in patients with hypertrophic cardiomyopathy

International Nuclear Information System (INIS)

Ohtsuki, Katsuichi; Sugihara, Hiroki; Umamoto, Ikuo

1992-01-01

123 I-β-methyl-p-iodophenylpentadecanoic acid ( 123 I-BMIPP) myocardial scintigraphy was performed in 13 patients with hypertrophic cardiomyopathy and compared with 201 Tl myocardial scintigraphy performed within 3 months for evaluating the clinical significance of 123 I-BMIPP myocardial scintigraphy. SPECT images were divided into 13 segments and segmental images were visually scored on a 4 (increased tracer uptake) to 0 (severely decreased tracer uptake) scale according to the tracer uptake. In comparison of 123 I-BMIPP early images and 201 Tl perfusion images, mismatches were seen in about 70% of all segments. The number of segments demonstrating lower myocardial uptake of 123 I-BMIPP was larger than that of 201 Tl. In hypertrophic regions, the tracer uptake of 123 I-BMIPP early images was significantly lower than that of 201 Tl images and the lower uptake of 123 I-BMIPP delayed images was more marked. In non-hypertrophic regions, no significant difference was seen between the tracer uptakes of 123 I-BMIPP early images and 201 Tl images but the tracer uptake of 123 I-BMIPP delayed images was significantly lower than that of 201 Tl images. The mismatch between the tracer uptakes of 123 I-BMIPP images and 201 Tl images was thought to be a reflection of disordered myocardial fatty acid metabolism. 'Washout', the difference between the tracer uptakes of 123 I-BMIPP early images and delayed images was also thought to be a reflection of disordered myocardial fatty acid metabolism. These results suggest that 123 I-BMIPP is a promising radiopharmaceutical for evaluating disordered myocardial fatty acid metabolism in patients with HCM. (author)

Spontaneous and α-adrenoceptor-induced contractility in human collecting lymphatic vessels require chloride

DEFF Research Database (Denmark)

Mohanakumar, Sheyanth; Majgaard, Jens; Telinius, Niklas

2018-01-01

- with the impermeant anion aspartate and inhibition of Cl- transport and channels with the clinical diuretics furosemide and bendroflumethiazide, as well as DIDS and NPPB. The molecular expression of calcium-activated chloride channels was investigated by RT-PCR and proteins localized using immunoreactivity....... Spontaneous and norepinephrine-induced contractility in human lymphatic vessels was highly abrogated after Cl- substitution with aspartate. 100‒300µM DIDS or NPPB inhibited spontaneous contractile behavior. Norepinephrine-stimulated tone was furthermore markedly abrogated by 200µM DIDS. Furosemide lowered...

Preoperative evaluation of myocardial viability by thallium-201 imaging in patients with old myocardial infarction who underwent coronary revascularization

International Nuclear Information System (INIS)

Naruse, Hitoshi; Ohyanagi, Mitsumasa; Iwasaki, Tadaaki; Miyamoto, Takashi; Fukuchi, Minoru

1992-01-01

The myocardial uptake and redistribution in thallium scintigraphy and the regional wall motion by echocardiography were evaluated by a semi-quantitative method in 42 patients who previously had myocardial infarction (50 target vessels) and underwent coronary revascularization. The aim of this study was to elucidate the significance of the initial image, delayed image and redistribution on thallium-201 scintigraphy for clinical diagnosis of the myocardial viability. As a semi-quantitative analysis, we used a bull's-eye display for thallium image and centerline method for echocardiographic wall motion, and compared the results before and after revascularization. As a result, the thallium grade improved postoperatively in all 17 areas which preoperatively had showed redistribution, and also in 11 of the 32 areas without preoperative redistribution. The sensitivity, specificity and accuracy of preoperative thallium redistribution for predicting myocardial viability were 61%, 100% and 78%, respectively, when the postoperative improvement in the thallium grade was used as the standard. The postoperative probability of improvement in the thallium grade increased in proportion to the preoperative grade (delayed image)(p<0.01). There was no correlation between the preoperative thallium delayed image and postoperative improvement in wall motion. Postoperative improvement in thallium image and wall motion could not be predicted from the preoperative wall motion. Thus, postoperative improvement in thallium images can be anticipated if redistribution is present on the preoperative thallium image, and the preoperative thallium delayed image is useful for predicting myocardial viability. Improvement in wall motion could not be predicted preoperatively by these methods. (author)

Application of 123I-labelled long-chained fatty acids for the study of myocardial metabolism

International Nuclear Information System (INIS)

Freundlieb, C.; Hoeck, A.; Vyska, F.; Feinendegen, L.E.; Machulla, H.J.; Stoecklin, G.

1978-01-01

Radioiodine-labelled fatty acids are useful tracers for myocardial imaging. The present study extends myocardial scintigraphy with ω-123-I-heptadecanoic acid to measuring myocardial metabolism. 4 normal individuals and 6 patients with cardiac disease received i.v. 1-2 mCi ω-123-I-heptadecanoic acid. Immediately fast serial scintigrams of the myocardium were taken for 30 minutes. Disappearance of the tracer, and appearance of anorganic 123-I, was measured in the peripheral blood. The myocardial images were of high quality later than 5 minutes after injection. By correcting for anorganic 123-I in the peripheral blood and the interstitium, the turnover of tracer in the myocardial cells could be measured. Activity was lost from the myocardium with a half time between 14 and 32 minutes. Within regions of old myocardials infarctions the half time of tracer loss was prolonged. The data clearly indicate the feasibility of using ω-123-I-heptadecanoic acid for measuring myocardial metabolism. (author)

Evaluation of the Differences of Myocardial Fibers between Acute and Chronic Myocardial Infarction: Application of Diffusion Tensor Magnetic Resonance Imaging in a Rhesus Monkey Model

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Wang, Yuqing [Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041 (China); CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190 (China); Cai, Wei [Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041 (China); Department of Radiology, Beijing Jishuitan Hospital, 4th Clinical Medical College of Peking University, Beijing 100035 (China); Wang, Lei [Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041 (China); Xia, Rui [Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041 (China); Department of Radiology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016 (China); Chen, Wei [Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041 (China); Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Yunnan 650032 (China); Zheng, Jie [Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO 63110 (United States); Gao, Fabao [Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041 (China)

2016-11-01

To understand microstructural changes after myocardial infarction (MI), we evaluated myocardial fibers of rhesus monkeys during acute or chronic MI, and identified the differences of myocardial fibers between acute and chronic MI. Six fixed hearts of rhesus monkeys with left anterior descending coronary artery ligation for 1 hour or 84 days were scanned by diffusion tensor magnetic resonance imaging (MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). Comparing with acute MI monkeys (FA: 0.59 ± 0.02; ADC: 5.0 ± 0.6 × 10{sup -4} mm{sup 2}/s; HA: 94.5 ± 4.4°), chronic MI monkeys showed remarkably decreased FA value (0.26 ± 0.03), increased ADC value (7.8 ± 0.8 × 10{sup -4}mm{sup 2}/s), decreased HA transmural range (49.5 ± 4.6°) and serious defects on endocardium in infarcted regions. The HA in infarcted regions shifted to more components of negative left-handed helix in chronic MI monkeys (-38.3 ± 5.0°–11.2 ± 4.3°) than in acute MI monkeys (-41.4 ± 5.1°–53.1 ± 3.7°), but the HA in remote regions shifted to more components of positive right-handed helix in chronic MI monkeys (-43.8 ± 2.7°–66.5 ± 4.9°) than in acute MI monkeys (-59.5 ± 3.4°–64.9 ± 4.3°). Diffusion tensor MRI method helps to quantify differences of mechanical microstructure and water diffusion of myocardial fibers between acute and chronic MI monkey's models.

Diagnostic value of exercise induced 18F-FDG myocardial metabolism scintigraphy in myocardial ischemia

International Nuclear Information System (INIS)

Shen Rui; He Zuoxiang; Shi Rongfang; Liu Xiujie; Tian Yueqin; Guo Feng; Wei Hongxing; Wu Yongjian; Qin Xuewen; Gao Runlin

2006-01-01

Objective: To evaluate the feasibility and diagnostic accuracy of exercise induced myocardial imaging with 18 F-fluorodeoxyglucose (FDG) in myocardial ischemia. Methods: Twenty-six patients with known or suspected coronary artery, disease (CAD) and with no prior myocardial infarction underwent simultaneous myocardial perfusion and metabolism imaging following intravenous injection of 99 Tc m -methoxy-isobutylisonitrile ( 99 Tc m -sestamibi) and 18 F-FDG at peak exercise. Subsequently rest perfusion imaging and coronary angiography (CAG) were performed in all patients. Exercise 18 F-FDG myocardial imaging was compared with 99 Tc m -sestamibi imaging and CAG. Results: In 22 patients with ≥50% narrowing over l coronary artery, 18 had perfusion abnormalities (sensitivity 82%), whereas 20 had abnormal myocardial 18 F-FDG uptake (sensitivity 91%, P>0.05). Patients with reversible (12 cases) or partial reversible (3 cases) perfusion abnormalities had increased myocardial 18 F-FDG uptake in abnormal perfusion segments. Compared with CAG, perfusion defect was seen in myocardial segments corresponding to 25 vascular territories of 51 vessels with ≥50% narrowing in 22 patients in 99 Tc m -sestamibi imaging (sensitivity 49%), whereas increased 18 F-FDG uptake was seen in 34 vascular territories (sensitivity 67%, P=0.008). Conclusions: Exercise induced myocardial ischemia can be imaged directly with 18 F-FDG. Combined exercise 18 F-FDG and 99 Tc m -sestamibi imaging provides a better assessment of exercise-induced myocardial ischemia as compared with exercise-rest perfusion imaging. (authors)

Localization and quantification of acute myocardial infarction by myocardial perfusion tomographic imaging

International Nuclear Information System (INIS)

Lin Xiufang; Min Changgeng; Lin Zhihu; Ke Ruoyi

1994-01-01

The authors reported the result of the quantification and localization of 30 clinically confirmed acute myocardial infarction patients in comparison with that of ECG. A left ventricle model was used to correct the area calculated by the method of Bull's eye. The result indicated that the infarction area calculated by the corrected Bull's eye method correlated closely with that determined by the ECG QRS scoring method (r = 0.706, P<0.01). Myocardial infarctions of all 30 patients were detected by both ECG and myocardial perfusion tomographic imaging. The accuracy of localization of myocardial infarction by myocardial perfusion imaging was similar to that of ECG in the anterior wall, anterior septum, anterior lateral and inferior wall, but superior to that of ECG in the apex, posterior lateral, posterior septum, and posterior wall

In vivo study of myocardial elastography under graded ischemia conditions

Energy Technology Data Exchange (ETDEWEB)

Lee, Wei-Ning; Provost, Jean; Konofagou, Elisa E [Department of Biomedical Engineering, Columbia University, New York, NY (United States); Fujikura, Kana [Department of Radiology, Columbia University, New York, NY (United States); Wang Jie, E-mail: ek2191@columbia.edu [Department of Medicine, Columbia University, New York, NY (United States)

2011-02-21

The capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction

[Myocardial contractility and hemodynamics in hypothyroidism].

Science.gov (United States)

Selivonenko, V G

1977-01-01

The author determined the phasic structure of the systole of the left ventricle by the method of polycardiography and hemodynamics in 20 patients suffering from hypothyrodism. Blood plasma and erythrocyte electrolytes were examined at the same time. Patients with hypothyroidism displayed a phasic syndrome of hypodynamia and a marked correlation between the phase of the synchronous contraction, the period of ejection, the strength of contraction of the left ventricle and the electrolyte content. Sodium and magnesium produced the greatest influence on the phasic structure of the systole; potassium and calcium had a lesser effect. The heart stroke volume diminished; as to the cardiac index, expenditure of the energy of cardiac contractions directed to the maintenance of movement of 1 litre of the minute blood volume; the external work, and the peripheral vascular resistance displayed no significant change.

Classification of myocardial infarction

DEFF Research Database (Denmark)

Saaby, Lotte; Poulsen, Tina Svenstrup; Hosbond, Susanne Elisabeth

2013-01-01

The classification of myocardial infarction into 5 types was introduced in 2007 as an important component of the universal definition. In contrast to the plaque rupture-related type 1 myocardial infarction, type 2 myocardial infarction is considered to be caused by an imbalance between demand...

Relation of plasma lipoprotein(a) with myocardial viability and left ventricular performance in survivors of myocardial infarction

International Nuclear Information System (INIS)

Aksoy, M.; Goktekin, O.; Gursurer, M.; Emre, A.; Bilge, M.; Yesilcimen, K.; Ersek, B.; Kepekci, Y.; Akdemir, I.

1999-01-01

Previous studies have reported that high serum lipoprotein(a) levels may be responsible for total occlusion of the infarct-related artery via inhibition of intrinsic fibrinolysis during acute myocardial infarction. We evaluated whether this would result in a greater extent of myocardial necrosis and impaired left ventricular function in patients with high lipoprotein(a) levels. Sixty-eight patients with prior myocardial infarction, who were not receiving thrombolytic therapy underwent coronary angiography and stress-redistribution-reinjection Tl-201 scintigraphy. Antegrade TIMI flow in the infarct-related artery was lower (1.54±1.14 vs 2.15±1.05; p=0.03) and the collateral index was higher (1.3±1.0 vs 0.8±0.9; p=0.07) in patients with high lipoprotein(a) levels (>30 mg/dl) compared to those with low lipoprotein(a) levels (≤30 mg/dl). Regional wall motion score index was lower (0.8±0.8 vs 1.4±0.5; p=0.008) and global ejection fraction was higher (46±10% vs 40±11%; p=0.03) in patients with low lipoprotein(a) levels. On SPECT images, the number of nonviable defects was higher in patients with high lipoprotein(a) levels (4.0±2.5 vs 1.9±1.3; p=0.0002), whereas the number of viable defects was higher in those with low lipoprotein(a) levels (2.5±1.8 vs 1.5±1.3; p=0.02). We conclude, that high lipoprotein(a) levels may prolong the occlusion of infarct-related artery during acute myocardial infarction and lead to a greater extent of myocardial necrosis and impaired left ventricular function. (author)

Direct Evidence that Myocardial Insulin Resistance following Myocardial Ischemia Contributes to Post-Ischemic Heart Failure

Science.gov (United States)

Fu, Feng; Zhao, Kun; Li, Jia; Xu, Jie; Zhang, Yuan; Liu, Chengfeng; Yang, Weidong; Gao, Chao; Li, Jun; Zhang, Haifeng; Li, Yan; Cui, Qin; Wang, Haichang; Tao, Ling; Wang, Jing; Quon, Michael J; Gao, Feng

2015-01-01

A close link between heart failure (HF) and systemic insulin resistance has been well documented, whereas myocardial insulin resistance and its association with HF are inadequately investigated. This study aims to determine the role of myocardial insulin resistance in ischemic HF and its underlying mechanisms. Male Sprague-Dawley rats subjected to myocardial infarction (MI) developed progressive left ventricular dilation with dysfunction and HF at 4 wk post-MI. Of note, myocardial insulin sensitivity was decreased as early as 1 wk after MI, which was accompanied by increased production of myocardial TNF-α. Overexpression of TNF-α in heart mimicked impaired insulin signaling and cardiac dysfunction leading to HF observed after MI. Treatment of rats with a specific TNF-α inhibitor improved myocardial insulin signaling post-MI. Insulin treatment given immediately following MI suppressed myocardial TNF-α production and improved cardiac insulin sensitivity and opposed cardiac dysfunction/remodeling. Moreover, tamoxifen-induced cardiomyocyte-specific insulin receptor knockout mice exhibited aggravated post-ischemic ventricular remodeling and dysfunction compared with controls. In conclusion, MI induces myocardial insulin resistance (without systemic insulin resistance) mediated partly by ischemia-induced myocardial TNF-α overproduction and promotes the development of HF. Our findings underscore the direct and essential role of myocardial insulin signaling in protection against post-ischemic HF. PMID:26659007

Effects of hypoxia and hypercapnia on geniohyoid contractility and endurance.

Science.gov (United States)

Salmone, R J; Van Lunteren, E

1991-08-01

Sleep apnea and other respiratory diseases produce hypoxemia and hypercapnia, factors that adversely affect skeletal muscle performance. To examine the effects of these chemical alterations on force production by an upper airway dilator muscle, the contractile and endurance characteristics of the geniohyoid muscle were examined in situ during severe hypoxia (arterial PO2 less than 40 Torr), mild hypoxia (PO2 45-65 Torr), and hypercapnia (PCO2 55-80 Torr) and compared with hyperoxic-normocapnic conditions in anesthetized cats. Muscles were studied at optimal length, and contractile force was assessed in response to supramaximal electrical stimulation of the hypoglossal nerve (n = 7 cats) or geniohyoid muscle (n = 2 cats). There were no significant changes in the twitch kinetics or force-frequency curve of the geniohyoid muscle during hypoxia or hypercapnia. However, the endurance of the geniohyoid, as reflected in the fatigue index (ratio of force at 2 min to initial force in response to 40-Hz stimulation at a duty cycle 0.33), was significantly reduced by severe hypoxia but not by hypercapnia or mild hypoxia. In addition, the downward shift in the force-frequency curve after the repetitive stimulation protocol was greater during hypoxia than hyperoxia, especially at higher frequencies. In conclusion, the ability of the geniohyoid muscle to maintain force output during high levels of activation is adversely affected by severe hypoxia but not mild hypoxia or hypercapnia. However, none of these chemical perturbations affected muscle contractility acutely.

Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

International Nuclear Information System (INIS)

Morton, M.J.; Armstrong, D.; Abi Gerges, N.; Bridgland-Taylor, M.; Pollard, C.E.; Bowes, J.; Valentin, J.-P.

2014-01-01

Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility

Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

Energy Technology Data Exchange (ETDEWEB)

Morton, M.J., E-mail: michael.morton@astrazeneca.com [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Armstrong, D.; Abi Gerges, N. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Bridgland-Taylor, M. [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Pollard, C.E.; Bowes, J.; Valentin, J.-P. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom)

2014-09-01

Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility.

Three-dimensional mapping of mechanical activation patterns, contractile dyssynchrony and dyscoordination by two-dimensional strain echocardiography: Rationale and design of a novel software toolbox

Directory of Open Access Journals (Sweden)

Cramer Maarten J

2008-05-01

of local 2-D echocardiographic deformation data into a 3-D model by dedicated software allows a comprehensive analysis of spatio-temporal distribution patterns of myocardial dyssynchrony, of the global left ventricular deformation and of newer indices that may better reflect myocardial dyscoordination and/or impaired ventricular contractile efficiency. The potential value of such an analysis is highlighted in two dyssynchronous pathologies that impose particular challenges to deformation imaging.

Temperature, air pollution, and mortality from myocardial infarction in São Paulo, Brazil

Directory of Open Access Journals (Sweden)

Sharovsky R.

2004-01-01

Full Text Available An increase in daily mortality from myocardial infarction has been observed in association with meteorological factors and air pollution in several cities in the world, mainly in the northern hemisphere. The objective of the present study was to analyze the independent effects of environmental variables on daily counts of death from myocardial infarction in a subtropical region in South America. We used the robust Poisson regression to investigate associations between weather (temperature, humidity and barometric pressure, air pollution (sulfur dioxide, carbon monoxide, and inhalable particulate, and the daily death counts attributed to myocardial infarction in the city of São Paulo in Brazil, where 12,007 fatal events were observed from 1996 to 1998. The model was adjusted in a linear fashion for relative humidity and day-of-week, while nonparametric smoothing factors were used for seasonal trend and temperature. We found a significant association of daily temperature with deaths due to myocardial infarction (P < 0.001, with the lowest mortality being observed at temperatures between 21.6 and 22.6ºC. Relative humidity appeared to exert a protective effect. Sulfur dioxide concentrations correlated linearly with myocardial infarction deaths, increasing the number of fatal events by 3.4% (relative risk of 1.03; 95% confidence interval = 1.02-1.05 for each 10 µg/m³ increase. In conclusion, this study provides evidence of important associations between daily temperature and air pollution and mortality from myocardial infarction in a subtropical region, even after a comprehensive control for confounding factors.

Quantitative estimation of myocardial thickness by the wall thickness map with Tl-201 myocardial SPECT and its clinical use

International Nuclear Information System (INIS)

Sekiai, Yasuhiro; Sawai, Michihiko; Murayama, Susumu

1988-01-01

To estimate the wall thickness of left ventricular myocardium objectively and quantitatively, we adopted the device of wall thickness map (WTM) with Tl-201 myocardial SPECT. For validation on measuring left ventricular wall thickness with SPECT, fundamental studies were carried out with phantom models, and clinical studies were performed in 10 cases comparing the results from SPECT with those in echocardiography. To draw the WTM, left ventricular wall thickness was measured using the cut off method from SPECT images obtained at 5.6 mm intervals from the base and middle of left ventricle: short-axis image for the base and middle of left ventricle and vertical and horizontal long-axis images for the apical region. Wall thickness was defined from the number of pixel above the cut off level. Results of fundamental studies disclosed that it is impossible to evaluate the thickness of less than 10 mm by Tl-201 myocardial SPECT but possible to discriminate wall thickness of 10 mm, 15 mm, and 20 mm by Tl-201 myocardial SPECT. Echocardiographic results supported the validity of WTM, showing a good linear correlation (r = 0.96) between two methods on measuring wall thickness of left ventricle. We conclude that the WTM applied in this report may be useful for objective and quantitative estimation of myocardial hypertrophy. (author)

Automated quantitative coronary computed tomography correlates of myocardial ischaemia on gated myocardial perfusion SPECT

International Nuclear Information System (INIS)

Graaf, Michiel A. de; Boogers, Mark J.; Veltman, Caroline E.; El-Naggar, Heba M.; Bax, Jeroen J.; Delgado, Victoria; Broersen, Alexander; Kitslaar, Pieter H.; Dijkstra, Jouke; Kroft, Lucia J.; Younis, Imad Al; Reiber, Johan H.; Scholte, Arthur J.

2013-01-01

Automated software tools have permitted more comprehensive, robust and reproducible quantification of coronary stenosis, plaque burden and plaque location of coronary computed tomography angiography (CTA) data. The association between these quantitative CTA (QCT) parameters and the presence of myocardial ischaemia has not been explored. The aim of the present investigation was to evaluate the association between QCT parameters of coronary artery lesions and the presence of myocardial ischaemia on gated myocardial perfusion single-photon emission CT (SPECT). Included in the study were 40 patients (mean age 58.2 ± 10.9 years, 27 men) with known or suspected coronary artery disease (CAD) who had undergone multidetector row CTA and gated myocardial perfusion SPECT within 6 months. From the CTA datasets, vessel-based and lesion-based visual analyses were performed. Consecutively, lesion-based QCT was performed to assess plaque length, plaque burden, percentage lumen area stenosis and remodelling index. Subsequently, the presence of myocardial ischaemia was assessed using the summed difference score (SDS ≥2) on gated myocardial perfusion SPECT. Myocardial ischaemia was seen in 25 patients (62.5 %) in 37 vascular territories. Quantitatively assessed significant stenosis and quantitatively assessed lesion length were independently associated with myocardial ischaemia (OR 7.72, 95 % CI 2.41-24.7, p 2 = 20.7) and lesion length (χ 2 = 26.0) to the clinical variables and the visual assessment (χ 2 = 5.9) had incremental value in the association with myocardial ischaemia. Coronary lesion length and quantitatively assessed significant stenosis were independently associated with myocardial ischaemia. Both quantitative parameters have incremental value over baseline variables and visually assessed significant stenosis. Potentially, QCT can refine assessment of CAD, which may be of potential use for identification of patients with myocardial ischaemia. (orig.)

Measuring the Contractile Response of Isolated Tissue Using an Image Sensor

Directory of Open Access Journals (Sweden)

David Díaz-Martín

2015-04-01

Full Text Available Isometric or isotonic transducers have traditionally been used to study the contractile/relaxation effects of drugs on isolated tissues. However, these mechanical sensors are expensive and delicate, and they are associated with certain disadvantages when performing experiments in the laboratory. In this paper, a method that uses an image sensor to measure the contractile effect of drugs on blood vessel rings and other luminal organs is presented. The new method is based on an image-processing algorithm, and it provides a fast, easy and non-expensive way to analyze the effects of such drugs. In our tests, we have obtained dose-response curves from rat aorta rings that are equivalent to those achieved with classical mechanic sensors.

Adenylate cyclase regulation in intact cultured myocardial cells

International Nuclear Information System (INIS)

Marsh, J.D.; Roberts, D.J.

1987-01-01

To examine the coupling of cardiac cell-surface β-adrenergic receptors to adenylate cyclase activation and contractile response, the authors studied this receptor-effector response system in monolayers of spontaneously contracting chick embryo ventricular cells under physiological conditions. The hydrophilic ligand 3 H-CGP12177 identified uniformly high-agonist affinity β-adrenergic receptors. Isoproterenol-stimulated cyclic AMP (cAMP) accumulation with 50% effective concentration at (EC 50 ) = 12.1 nM and augmented contractile response with EC 50 = 6 nM under identical conditions. One micromolar isoproterenol induced receptor loss from the cell surface with t/sub 1/2/ = 13.2 min; under identical conditions cAMP content declined with t/sub 1/2/ = 13.5 min and contractile response with t/sub 1/2/ = 20.7 min. After agonist removal cAMP response recovered with t/sub 1/2/ = 15.7 min and receptors with t/sub 1/2/ = 24.7 min. Sixty minutes after agonist removal there was recovery of 52% of maximal cAMP responsiveness and 82% of the initial number of receptors; receptor occupancy was associated with 78% of initial contractile response. Agonist affinity for cell-surface receptors was changed only modestly by agonist exposure. They conclude that for this system there is relatively close coupling between high-affinity receptors, adenylate cyclase stimulation, and contractile response

In vitro contractile effects of agents used in the clinical management of postpartum haemorrhage.

Science.gov (United States)

Morrison, John J; Crosby, David A; Crankshaw, Denis J

2016-10-15

Uterine atony is a major cause of postpartum haemorrhage and maternal mortality. However, the comparative pharmacology of agents used to treat this condition is poorly understood. This study evaluates, using human pregnant myometrium in vitro, a range of contractile parameters for agents used in the clinical treatment of atonic postpartum haemorrhage. The effects of oxytocin, carbetocin, ergometrine, carboprost, syntometrine and misoprostol were investigated in 146 myometrial strips from 19 donors. The potency and maximal response values were obtained, and compared, using both maximal amplitude and mean contractile force as indices of contraction. Single, EC50 concentrations of the agents were administered and both force and contraction peak parameters were compared during a 15-min exposure. Differences were considered significant when Poxytocin and carbetocin being the most potent. The most important difference between the agents was in their ability to increase the mean contractile force, with oxytocin superior to all agents except syntometrine. In single dose experiments, mean contractile force was the parameter that separated the agents. In this respect, oxytocin was not statistically different from carboprost or syntometrine, but was superior to all other agents. These findings support a clear role for oxytocin as the first line agent for treatment of postpartum haemorrhage and raise doubts about the potential clinical usefulness of misoprostol. Copyright © 2016 Elsevier B.V. All rights reserved.

Myocardial remodeling and bioelectric changes in tachycardia-induced heart failure in dogs

Energy Technology Data Exchange (ETDEWEB)

Song, B.; Wang, B.N.; Chen, D.N.; Luo, Z.G. [Department of Cardiovascular Medicine, The First Affiliated Hospital, Anhui Medical University, HeFei, Anhui Province (China)

2013-09-06

In this study, electrical and structural remodeling of ventricles was examined in tachycardia-induced heart failure (HF). We studied two groups of weight-matched adult male mongrel dogs: a sham-operated control group (n=5) and a pacing group (n=5) that underwent ventricular pacing at 230 bpm for 3 weeks. Clinical symptoms of congestive HF were observed in both groups. Their hemodynamic parameters were determined and the severity of the HF was evaluated by M-mode echocardiography. Changes in heart morphology were observed by scanning electron and light microscopy. Ventricular action potential duration (APD), as well as the 50 and 90% APD were measured in both groups. All dogs exhibited clinical symptoms of congestive HF after rapid right ventricular pacing for 3 weeks. These data indicate that rapid, right ventricular pacing produces a useful experimental model of low-output HF in dogs, characterized by biventricular pump dysfunction, biventricular cardiac dilation, and non-ischemic impairment of left ventricular contractility. Electrical and structural myocardial remodeling play an essential role in congestive HF progression, and should thus be prevented.

Myocardial images in nonacute coronary and noncoronary heart diseases

International Nuclear Information System (INIS)

Poe, N.D.; Eber, L.M.; Norman, A.S.; Selin, C.E.; Terao, E.N.

1977-01-01

To determine the variables that might affect interpretability of myocardial perfusion images in patients with acute myocardial infarctions, images obtained following intravenous administration of potassium-43 or cesium-129 were evaluated in 68 patients with nonacute coronary or noncoronary heart diseases, who were undergoing cardiac catheterization. Severe coronary arterial disease usually produces no distinctive perfusion defects in the resting state. Remote infarcts likewise tend to remain undetectable unless accompanied by wall-motion disturbances that can be detected by ventriculography. Left ventricular hypertrophy or cardiac dilatation can produce perfusion patterns indistinguishable from the ischemic defects of infarction. Right ventricular hypertrophy can cause image alterations that mimic infarcts in the left ventricle. In patients with acute myocardial infarction, sequential imaging studies with perfusion indicators should be of value in determining the effects of various therapeutic maneuvers on regional myocardial perfusion, but variations caused by conditions other than acute vascular occlusion limit the usefulness of perfusion imaging for diagnosing acute infarction. In suspected acute infarction, perfusion imaging will be used most effectively in conjunction with other imaging or nonimaging procedures that show the presence of damaged or necrotic myocardium. The information derived from this study should be generally applicable to the interpretation of imaging results obtained with the newer indicators of myocardial perfusion now in use or under development

[Effectiveness of various dopamine doses in acute myocardial ischemia complicated by cardiogenic shock (an experimental study)].

Science.gov (United States)

Kipshidze, N N; Korotkov, A A; Marsagishvili, L A; Prigolashvili, T Sh; Bokhua, M R

1981-06-01

The effect of various doses of dopamine on the values of cardiac contractile and hemodynamic function under conditions of acute two-hour ischemia complicated by cardiogenic shock was studied in 27 experiments on dogs. In a dose of 5 microgram/kg/min dopamine caused an optimum increase in cardiac productive capacity, reduction of peripheral resistance, adequate increase in coronary circulation and decrease in ST segment depression on the ECG. Infusion of 10 microgram/kg/min dopamine usually caused myocardial hyperfunction with an increase in total peripheral resistance and cardiac performance. Maximum dopamine doses (10 microgram/kg/min and more) were effective in the areactive form of cardiogenic shock. In longterm dopamine infusion it is necessary to establish continuous control over the hemodynamic parameters and the ECG to prevent aggravation of ischemia and for stage-by-stage reduction of the drug concentration and determination of the minimum maintenance dose.

Genetic fuzzy system predicting contractile reactivity patterns of small arteries

DEFF Research Database (Denmark)

Tang, J; Sheykhzade, Majid; Clausen, B F

2014-01-01

strategies. Results show that optimized fuzzy systems (OFSs) predict contractile reactivity of arteries accurately. In addition, OFSs identified significant differences that were undetectable using conventional analysis in the responses of arteries between groups. We concluded that OFSs may be used...

Myocardial contusion in patients with blunt chest trauma as evaluated by thallium 201 myocardial scintigraphy

International Nuclear Information System (INIS)

Bodin, L.; Rouby, J.J.; Viars, P.

1988-01-01

Fifty five patients suffering from blunt chest trauma were studied to assess the diagnosis of myocardial contusion using thallium 201 myocardial scintigraphy. Thirty-eight patients had consistent scintigraphic defects and were considered to have a myocardial contusion. All patients with scintigraphic defects had paroxysmal arrhythmias and/or ECG abnormalities. Of 38 patients, 32 had localized ST-T segment abnormalities; 29, ST-T segment abnormalities suggesting involvement of the same cardiac area as scintigraphic defects; 21, echocardiographic abnormalities. Sixteen patients had segmental hypokinesia involving the same cardiac area as the scintigraphic defects. Fifteen patients had clinical signs suggestive of myocardial contusion and scintigraphic defects. Almost 70 percent of patients with blunt chest trauma had scintigraphic defects related to areas of myocardial contusion. When thallium 201 myocardial scintigraphy directly showed myocardial lesion, two-dimensional echocardiography and standard ECG detected related functional consequences of cardiac trauma

Impacts of acute severe pulmonary regurgitation on right ventricular geometry and contractility assessed by tissue-Doppler echocardiography

DEFF Research Database (Denmark)

Kjaergaard, Jesper; K. Iversen, Kasper; G Vejlstrup, Niels

2010-01-01

AIMS: Little is known of the impact of acute right ventricular (RV) volume overload on RV function. We assessed the impact of acute severe pulmonary regurgitation (PR) on global and regional RV function by applying novel quantitative echocardiographic markers of myocardial performance in an animal...

Impacts of acute severe pulmonary regurgitation on right ventricular geometry and contractility assessed by tissue-Doppler echocardiography

DEFF Research Database (Denmark)

Kjaergaard, Jesper; Iversen, Kasper K; Vejlstrup, Niels G

2010-01-01

Little is known of the impact of acute right ventricular (RV) volume overload on RV function. We assessed the impact of acute severe pulmonary regurgitation (PR) on global and regional RV function by applying novel quantitative echocardiographic markers of myocardial performance in an animal model....

2-Deoxyadenosine triphosphate restores the contractile function of cardiac myofibril from adult dogs with naturally occurring dilated cardiomyopathy

OpenAIRE

Cheng, Yuanhua; Hogarth, Kaley A.; O'Sullivan, M. Lynne; Regnier, Michael; Pyle, W. Glen

2015-01-01

1) First report to characterize and define the contractile kinetics and defects associated with naturally occurring dilated cardiomyopathy (DCM) in dogs. 2) Novel findings that dATP is able to reverse the contractile defects associated with naturally occurring canine DCM.

Exercise induced ST elevation and residual myocardial ischemia in previous myocardial infarction

International Nuclear Information System (INIS)

Shimonagata, Tsuyoshi; Nishimura, Tsunehiko; Uehara, Toshiisa; Hayashida, Kohei; Saito, Muneyasu; Sumiyoshi, Tetsuya

1987-01-01

The purpose of this study was to evaluate the clinical significance of stress induced ST elevation on infarcted area in 65 patients with previous myocardial infarction (single vessel disease) who had stress thallium scan. Stress induced ST changes on infarcted area were compared with quantitative assessment of myocardial ischemia (thallium ischemic score; TIS) and extent of myocardial infarction (defect score; DS) derived from circumferential profile analysis. In patients with previous myocardial infarction in less than 3 month from the onset (n = 36), left ventricular ejection fraction (LVEF) and extent of abnormal LV wall motion were not significantly different between patients with stress induced ST elevation ( ≥ 2 mm, n = 26) and those with stress induced ST elevation ( < 2 mm, n = 10), while, in patients with previous myocardial infarction in more than 3 month (n = 29), patients with stress induced ST elevation ( ≥ 2 mm, n = 15) showed left ventricular dyskinesis more frequently than those with ST elevation ( < 2 mm, n = 14). In addition, the former showed significantly higher DS and significantly lower TIS than the latter. In patients with previous myocardial infarction in less than 3 month, patients with ST elevation ( ≥ 2 mm, n = 15) with prominent upright T wave (n = 15) had transient thallium defect in infarcted area in 73 % and they had significantly higher LVEF and TIS than those with ST elevation ( < 2 mm, n = 11). These results indicated that ST elevation in infarcted area reflect different significance according to the recovery of injured myocardium and stress induced ST elevation with prominent upright T wave in infarcted area reflect residual myocardial ischemia in less than 3 month from the onset of myocardial infarction. (author)

Acute myocardial infarct imaging with indium-111-labeled monoclonal antimyosin Fab

International Nuclear Information System (INIS)

Khaw, B.A.; Yasuda, T.; Gold, H.K.; Leinbach, R.C.; Johns, J.A.; Kanke, M.; Barlai-Kovach, M.; Strauss, H.W.; Haber, E.

1987-01-01

Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of 54 patients (96.3%) with acute myocardial infarction. Infarcts were visualized when coronary arteries were persistently occluded (n = 10), became patent after thrombolysis (n = 33), or became patent after spontaneous reperfusion (n = 7). Posteroinferolateral visualizations were obtained in two patients with clinical and enzymatic evidence of infarction but normal electrocardiograms. Of the two patients in whom no infarcts were visualized, one had an anterior myocardial infarct. This patient underwent successful thrombolytic therapy, with attendant minimization of creatine kinase release. The other patient had a small, nonreperfused inferior myocardial infarct. Five patients with a history of remote infarction and acute necrosis showed antimyosin uptake only in regions concordant with the acute episodes of infarction, and radiolabeled antimyosin Fab localized in neither old infarcts nor normal, noninfarcted myocardium. Antimyosin Fab scintigraphy, thus, appears to be a highly specific means of delineating necrotic myocardium, at least in this limited and selected group of patients

Myocardial infarction in the conscious dog: three dimensional mapping of infarct, collateral flow and region at risk

International Nuclear Information System (INIS)

Jugdutt, B.I.; Hutchins, G.M.; Bulkley, B.H.; Becker, L.C.

1979-01-01

Myocardial infarcts were examined in dogs to determine the spatial distribution of infarction in the region at risk and the relation between infarction and collateral blood flow. Permanent occlusion of the left circumflex (LC) coronary artery at a constant site was made in 27 conscious dogs that were sacrificed 2 days later. The anatomic region at risk was defined by postmortem coronary arteriography as the volume of the occluded LC coronary bed. The masses of the left ventricle (LV), infarct (I) and risk region (R) were calculated from planimetered areas of weighted bread-loaf sections of LV. Infarct size was directly related to the mass of the risk region (I = 0.53 R - 9.87; r = 0.97; p < 0.001). There was no infarction when R was less than about 20 g or 20% of the LV. The infarcts were mainly subendocardial and tapered from base to apex of the LV; 34% of the risk region became infarcted at the base compared with 22% at the apex. In all dogs, a significant rim of noninfarcted myocardium was identified at lateral aspects of the risk region, even at the endocardial surface. Using 9-μ radioactive microspheres, initial postocclusion flow at the margin of the infarct, but well within the risk region, was higher than at the center, and outer flows were higher than inner flows. Postocclusion flow was even higher in the noninfarcted rim within the risk region, but was still significantly less than flow to normal, nonrisk areas. Collateral flows throughout the risk region increased during the first hour after occlusion, and were even higher at 2 days.Epicardially and laterally within the anatomic risk region there is a substantial amount of tissue that does not infarct despite initally reduced blood flow

Changes in contractile activation characteristics of rat fast and slow skeletal muscle fibres during regeneration.

Science.gov (United States)

Gregorevic, Paul; Plant, David R; Stupka, Nicole; Lynch, Gordon S

2004-07-15

Damaged skeletal muscle fibres are replaced with new contractile units via muscle regeneration. Regenerating muscle fibres synthesize functionally distinct isoforms of contractile and regulatory proteins but little is known of their functional properties during the regeneration process. An advantage of utilizing single muscle fibre preparations is that assessment of their function is based on the overall characteristics of the contractile apparatus and regulatory system and as such, these preparations are sensitive in revealing not only coarse, but also subtle functional differences between muscle fibres. We examined the Ca(2+)- and Sr(2+)-activated contractile characteristics of permeabilized fibres from rat fast-twitch (extensor digitorum longus) and slow-twitch (soleus) muscles at 7, 14 and 21 days following myotoxic injury, to test the hypothesis that fibres from regenerating fast and slow muscles have different functional characteristics to fibres from uninjured muscles. Regenerating muscle fibres had approximately 10% of the maximal force producing capacity (P(o)) of control (uninjured) fibres, and an altered sensitivity to Ca(2+) and Sr(2+) at 7 days post-injury. Increased force production and a shift in Ca(2+) sensitivity consistent with fibre maturation were observed during regeneration such that P(o) was restored to 36-45% of that in control fibres by 21 days, and sensitivity to Ca(2+) and Sr(2+) was similar to that of control (uninjured) fibres. The findings support the hypothesis that regenerating muscle fibres have different contractile activation characteristics compared with mature fibres, and that they adopt properties of mature fast- or slow-twitch muscle fibres in a progressive manner as the regeneration process is completed.

A contractile and counterbalancing adhesion system controls the 3D shape of crawling cells.

Science.gov (United States)

Burnette, Dylan T; Shao, Lin; Ott, Carolyn; Pasapera, Ana M; Fischer, Robert S; Baird, Michelle A; Der Loughian, Christelle; Delanoe-Ayari, Helene; Paszek, Matthew J; Davidson, Michael W; Betzig, Eric; Lippincott-Schwartz, Jennifer

2014-04-14

How adherent and contractile systems coordinate to promote cell shape changes is unclear. Here, we define a counterbalanced adhesion/contraction model for cell shape control. Live-cell microscopy data showed a crucial role for a contractile meshwork at the top of the cell, which is composed of actin arcs and myosin IIA filaments. The contractile actin meshwork is organized like muscle sarcomeres, with repeating myosin II filaments separated by the actin bundling protein α-actinin, and is mechanically coupled to noncontractile dorsal actin fibers that run from top to bottom in the cell. When the meshwork contracts, it pulls the dorsal fibers away from the substrate. This pulling force is counterbalanced by the dorsal fibers' attachment to focal adhesions, causing the fibers to bend downward and flattening the cell. This model is likely to be relevant for understanding how cells configure themselves to complex surfaces, protrude into tight spaces, and generate three-dimensional forces on the growth substrate under both healthy and diseased conditions.

Carboxyl-terminal-dependent recruitment of nonmuscle myosin II to megakaryocyte contractile ring during polyploidization.

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Badirou, Idinath; Pan, Jiajia; Legrand, Céline; Wang, Aibing; Lordier, Larissa; Boukour, Siham; Roy, Anita; Vainchenker, William; Chang, Yunhua

2014-10-16

Endomitosis is a unique megakaryocyte (MK) differentiation process that is the consequence of a late cytokinesis failure associated with a contractile ring defect. Evidence from in vitro studies has revealed the distinct roles of 2 nonmuscle myosin IIs (NMIIs) on MK endomitosis: only NMII-B (MYH10), but not NMII-A (MYH9), is localized in the MK contractile ring and implicated in mitosis/endomitosis transition. Here, we studied 2 transgenic mouse models in which nonmuscle myosin heavy chain (NMHC) II-A was genetically replaced either by II-B or by a chimeric NMHCII that combined the head domain of II-A with the rod and tail domains of II-B. This study provides in vivo evidence on the specific role of NMII-B on MK polyploidization. It demonstrates that the carboxyl-terminal domain of the heavy chains determines myosin II localization to the MK contractile ring and is responsible for the specific role of NMII-B in MK polyploidization.

Chronic clenbuterol treatment compromises force production without directly altering skeletal muscle contractile machinery

Science.gov (United States)

Py, G; Ramonatxo, C; Sirvent, P; Sanchez, A M J; Philippe, A G; Douillard, A; Galbès, O; Lionne, C; Bonnieu, A; Chopard, A; Cazorla, O; Lacampagne, A; Candau, R B

2015-01-01

Clenbuterol is a β2-adrenergic receptor agonist known to induce skeletal muscle hypertrophy and a slow-to-fast phenotypic shift. The aim of the present study was to test the effects of chronic clenbuterol treatment on contractile efficiency and explore the underlying mechanisms, i.e. the muscle contractile machinery and calcium-handling ability. Forty-three 6-week-old male Wistar rats were randomly allocated to one of six groups that were treated with either subcutaneous equimolar doses of clenbuterol (4 mg kg−1 day−1) or saline solution for 9, 14 or 21 days. In addition to the muscle hypertrophy, although an 89% increase in absolute maximal tetanic force (Po) was noted, specific maximal tetanic force (sPo) was unchanged or even depressed in the slow twitch muscle of the clenbuterol-treated rats (P muscle contraction and relaxation force kinetics indicated that clenbuterol treatment significantly reduced the rate constant of force development and the slow and fast rate constants of relaxation in extensor digitorum longus muscle (P fast rate constant of relaxation in soleus muscle (P fibres (fast twitch fibres) from clenbuterol-treated animals demonstrated decreased amplitude after 14 days (−19%, P < 0.01) and 21 days (−25%, P < 0.01). In conclusion, we showed that chronic clenbuterol treatment reduces contractile efficiency, with altered contraction and relaxation kinetics, but without directly altering the contractile machinery. Lower Ca2+ release during contraction could partially explain these deleterious effects. PMID:25656230

Myosin phosphorylation improves contractile economy of mouse fast skeletal muscle during staircase potentiation.

Science.gov (United States)

Bunda, Jordan; Gittings, William; Vandenboom, Rene

2018-01-30

Phosphorylation of the myosin regulatory light chain (RLC) by skeletal myosin light chain kinase (skMLCK) potentiates rodent fast twitch muscle but is an ATP-requiring process. Our objective was to investigate the effect of skMLCK-catalyzed RLC phosphorylation on the energetic cost of contraction and the contractile economy (ratio of mechanical output to metabolic input) of mouse fast twitch muscle in vitro (25°C). To this end, extensor digitorum longus (EDL) muscles from wild-type (WT) and from skMLCK-devoid (skMLCK -/- ) mice were subjected to repetitive low-frequency stimulation (10 Hz for 15 s) to produce staircase potentiation of isometric twitch force, after which muscles were quick frozen for determination of high-energy phosphate consumption (HEPC). During stimulation, WT muscles displayed significant potentiation of isometric twitch force while skMLCK -/- muscles did not (i.e. 23% versus 5% change, respectively). Consistent with this, RLC phosphorylation was increased ∼3.5-fold from the unstimulated control value in WT but not in skMLCK -/- muscles. Despite these differences, the HEPC of WT muscles was not greater than that of skMLCK -/- muscles. As a result of the increased contractile output relative to HEPC, the calculated contractile economy of WT muscles was greater than that of skMLCK -/- muscles. Thus, our results suggest that skMLCK-catalyzed phosphorylation of the myosin RLC increases the contractile economy of WT mouse EDL muscle compared with skMLCK -/- muscles without RLC phosphorylation. © 2018. Published by The Company of Biologists Ltd.

Sex-specific criteria for interpretation of thallium-201 myocardial uptake and washout studies

International Nuclear Information System (INIS)

Rabinovitch, M.; Suissa, S.; Elstein, J.

1986-01-01

A study was undertaken to determine the effect of gender on criteria for the quantitative analysis of exercise-redistribution 201 Tl myocardial scintigraphy. The studies of 26 normal females and 23 normal males were subjected to bilinear interpolative background subtraction and horizontal profile analysis. Significant sexual differences were found in both regional uptake ratios and washout rates. These differences primarily reflected a proportionately decreased anterior and upper septal uptake in females, and faster washout in females. Faster myocardial 201 Tl washout rates in females could not be clearly ascribed to either a physiological or artifactual explanation. It is concluded that since important differences exist between males and females in the detected pattern of 201 Tl myocardial uptake and washout, sex-specific criteria may enhance the predictive accuracy of exercise-redistribution 201 Tl myocardial scintigraphy

Myocardial ischemia in hypertrophic cardiomyopathy

International Nuclear Information System (INIS)

Lima Filho, Moyses de Oliveira; Figueiredo, Geraldo L.; Simoes, Marcus V.; Pyntia, Antonio O.; Marin Neto, Jose Antonio

2000-01-01

Myocardial ischemia in hypertrophic cardiomyopathy is multifactorial and explains the occurrence of angina, in about 50% of patients. The pathophysiology of myocardial ischemia may be explained by the increase of the ventricular mass and relative paucity of the coronary microcirculation; the elevated ventricular filling pressures and myocardial stiffness causing a compression of the coronary microvessels; the impaired coronary vasodilator flow reserve caused by anatomic and functional abnormalities; and the systolic compression of epicardial vessel (myocardial bridges). Myocardial ischemia must be investigated by perfusion scintigraphic methods since its presence influences the prognosis and has relevant clinical implications for management of patients. Patients with hypertrophic cardiomyopathy and documented myocardial ischemia usually need to undergo invasive coronary angiography to exclude the presence of concomitant atherosclerotic coronary disease. (author)

Relationship between availability of the collateral circulation and ischemic time for myocardial viability in patients with acute myocardial infarction. Assessment by technetium-99m tetrofosmin single photon emission computed tomography

International Nuclear Information System (INIS)

Kanamori, Norio; Kondo, Makoto; Fukuoka, Yoshitomo; Higuchi, Hirokazu; Kubota, Tomoyuki; Matsuoka, Ryota; Araki, Makoto; Tanio, Hitoshi; Doyama, Kiyoshi

2007-01-01

Myocardial accumulation before reperfusion therapy of a radioactive tracer in the completely occluded region, conceivably reflects the viability of myocytes and degree of collateral circulation. To confirm this, the present study examined the relationship in the title. Subjects were 33 patients (F 7, M 26; average age 65 y) of the first 1-branch acute myocardial infarction and of TIMI (thrombolysis in myocardial infarction trial) grade 0 who recovered to TIMI 3 within 12 hr after attack: 99m Tc-tetrofosmin, 740 MBq, was intravenously injected before reperfusion and just after which, SPECT imaging (TF-SPECT) was conducted with Toshiba E. CAM, and regional severity score index (RSSI) (0-3) was calculated. About 1 week later, to see the myocardial viability in the chronic phase, GITl (Glucose-Insulin- 201 Tl) (111 MBq) SPECT was performed 30 min after its injection to calculate RSSI as above, and the echocardiography with ALOKA Pro Sound SSD-4000 or SIEMENS Acuson SEQUOIA C256 was done to calculate the regional wall motion score index (RWMSI) (0-4). RWMSI was found significantly correlated with TF-RSSI, the group with the better collateral circulation (TF-RSSI, 1.9 or less) exhibited significantly lower GITl-RSSI and RWMSI, and correlation between the ischemic time and neither TF-RSSI, GITl-RSSI nor RWMSI was found. Thus under these conditions, the development of collateral vessels was found to have potential protective effects on myocardium independently on the ischemic time. (T.I.)

Modifying influence of incorporated 137Cs upon the mechanisms of adrenergic control over contractile myucard function

International Nuclear Information System (INIS)

Lobanok, L.M.; Bulanova, K.Ya.; Gerasimovich, N.V.; Sineleva, M.V.; Milyutin, A.A.

1994-01-01

Incorporated 137 Cs (absorbed dose of 0.26 Gy) causes decrease of myocard's contractile function and intropic response to β-adrenagonists effect, isoproterenol-stimulated adenylate cyclase activity and β-adrenoreceptors affinity. Adrenergic effects, mediated by α-adrenergic structures on heart contractile function, on the contrary, become stronger, that is due to the increase of the receptors' dencity on sarcolemma surface