Background Duchenne (DMD) and Becker (BMD) muscular dystrophy (MD) are inherited X-linked disease characterized by progressive skeletal muscle degeneration and myocardial involvement and caused by a mutation on dystrophin gene (Xp21). Dystrophin is a sarcolemal protein that links the cytoskeleton to the basal lamina and is essential for maintenance of the muscular membrane integrity during musc...

Krueger JW, Pollack GH (1975) Myocardial sarcomere dynamics during isometric contraction. J Physiol (Lond) 251: 627-643 Krueger JW, Strobeck JE (1978) Sarcomere relaxation in intact cardiac muscle. Eur J Cardiol 7 (suppl): 79-96 Lakatta EG, Jewell BR (1977) Length-dependent activation. Its effects on the length-tension relation in cat ventricular muscle. Circ Res 40: 251-267 Langer GA (1973) He...

Background In diabetic cardiomyopathy (DCM), ventricular remodelling consists in a progressive impairment of myocardial contraction (evolving from diastolic to combined diastolicsystolic dysfunction) occurring regardless of ischemic heart disease, hypertension or other macrovascular complications, which ultimately leads to heart failure. Early stages of DCM are asymptomatic and characterised by...

It is known that the heart interacts with and adapts to its venous and arterial loading conditions. Various experimental studies and modeling approaches have been developed to investigate the underlying mechanisms. This paper presents a model of the left ventricle derived based on nonlinear stress-length myocardial characteristics integrated over truncated ellipsoidal geometry, and second-order...

The effects of cardiac glycosides on myocardial oxygen consumption (MVo2) have been investigated extensively, and although the results of these studies have not been entirely uniform, it is now generally considered that these agents are "the only drugs which increase the force of contraction of the myocardium without at the same time increasing oxygen consumption" (1). The finding in previous i...

Strain and strain rate imaging have been shown to be useful for the assessment of regional myocardial function. However, some of the mechanisms of transition in myocardial contraction/relaxation remain unclear. In this study, the RF echoes from the left ventricular (LV) wall were acquired in both the longitudinal-axis view and the apical view by scanning ultrasonic beams sparsely to improve the...

The effects of cardiac glycosides on myocardial oxygen consumption (MVo2) have been investigated extensively, and although the results of these studies have not been entirely uniform, it is now generally considered that these agents are "the only drugs which increase the force of contraction of the myocardium without at the same time increasing oxygen consumption" (1). The finding in previous i...

The purpose of our study was to investigate whether loss of myocardial contraction immediately after coronary occlusion was nonuniform, and if pretreatment with carvedilol, a vasodilating nonselective beta-adrenoceptor antagonist, could retard loss of contraction after coronary artery occlusion. Feline hearts were subjected to acute regional ischemia by total occlusion of the left anterior desc...

The regulation of myocardial contraction and relaxation kinetics is currently incompletely understood. When the amplitude of contraction is increased via the Frank-Starling mechanism, the kinetics of the contraction slow down, but when the amplitude of contraction is increased with either an increase in heart rate or via β-adrenergic stimulation, the kinetics speed up. It is also unknown how ph...

M yocardial perfusion occurs primarily in diastole since systolic contraction transiently impedes coronary blood flow especially to the subendocardium. Thus, myocardial bridges replicate the normal microvascular physiology of high diastolic and low systolic flow, albeit at the level of the epicardial coronary artery. Because marked myocardial bridges are not common during invasive angiography, ...