Among the many causes of myocardial injury that can lead to congestive heart failure (CHF), myocardial infarction (MI) is the most common in the developed world. The hallmark features of heart failure include reduced contractile function manifested as blunted, slowed, dysynchronous contraction and impaired relaxation. The physiological positive force–frequency relationship and increased myocard...

Twenty-one patients with various heart diseases undergoing the coronary sinus catheterization had myocardial blood flow studies before and during isometric handgrip exercise. At 30% of the maximal voluntary contraction (MVC), handgrip increased both coronary sinus blood flow by 19.8% and myocardial O2 consumption by 21.0% on the average as compared to those at rest. At 20% of MVC, the increase ...

muscle fatigue assessment has been the basis of numerous studies, specifically, in neuromuscular rehabilitation and the applications of fessystems. various emgbased techniques, in time and frequency domains, have been investigatedover years for the detection and evaluationof this phenomenon. the main objective of this study has beento evaluate the efficiency of applying a number of techniques w...

doppler-derived myocardial performance index (mpi) , defined as the s um of isovolumetric contraction and relaxation durations divided by ejection time, is an easily measured and reproducible index that shows both systolic and diastolic myocardial function. the goal of this study was to define normal values of right ventricular mpi in neonates in the first 48 to 72 hours of life. fifty-one quie...

doppler-derived myocardial performance index (mpi), defined as the sum of isovolumetric contraction and relaxation durations divided by ejection time, is an easily measured and reproducible index that shows both systolic and diastolic myocardial function. the goal of this study was to define normal values of right ventricular (rv) mpi in neonates in the first 48 to 72 hours of life. fifty-one q...

background: we sought to assess right ventricular (rv) systolic and diastolic functions via tissue doppler imaging (tdi) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts. methods: a tissue doppler velocity study via doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) ...

PURPOSE Previous studies demonstrated that low-dose dobutamine stress cine magnetic resonance imaging (MRI) and delayed contrast-enhanced MRI can provide assessments of myocardial viability. The purpose of this study was to evaluate the comparative diagnostic values of dobutamine cine MRI and delayed contrast-enhanced MRI for predicting functional recovery of myocardial contraction in patients ...

Echocardiography was used to study left ventricular size and contraction in 128 patients with isolated aortic valve disease 45 patients with aortic stenosis, 25 with mixed aortic valve disease and 58 with aortic regurgitation. Left ventricular measurements included the end-diastolic internal dimension (LVIDd), mural thickness (PWTd), an index of circumferential myocardial contraction fractional...

The effects of cold air inhalation and isometric exercise on coronary blood flow are currently unknown, despite the fact that both cold air and acute exertion trigger angina in clinical populations. In this study, we used transthoracic Doppler echocardiography to measure coronary blood flow velocity (CBV; left anterior descending coronary artery) and myocardial function during cold air inhalati...

UNLABELLED There is intense controversy as to the mechanisms underlying chronic but reversible left ventricular (LV) ischemic dysfunction. The aim of this study was to investigate the physiology underlying this condition in a canine model of noninfarcted collateral-dependent myocardium. METHODS Six mongrel dogs were instrumented with ameroid constrictors on the left circumflex and right coron...