BACKGROUND Abnormalities of intracellular calcium handling are widely recognized as a common hallmark of heart failure in animal models and humans. Modifying the interaction of phospholamban (PLB) with the sarcoplasmic reticulum ATPase (SERCA) by PLB mutants improves cardiac function but may also lead to heart failure. In this study we describe the in vivo effects of a new approach to modify th...

Although it is well known that mutations in the cardiac regulatory myosin light chain-2 (mlc-2) gene cause hypertrophic cardiomyopathy, the precise in vivo structural and functional roles of MLC-2 in the heart are only poorly understood. We have isolated a mutation in zebrafish, tell tale heart (tel(m225)), which selectively perturbs contractility of the embryonic heart. By positional cloning, ...

Metabolic adaptation to limited supplies of oxygen and nutrients plays a pivotal role in health and disease. Heart attack results from insufficient delivery of oxygen and nutrients to the heart, where cardiomyocytes die and cardiac fibroblasts proliferate--the latter causing scar formation, which impedes regeneration and impairs contractility of the heart. We postulated that cardiac fibroblasts...

Major heart diseases such as ischemia and hypertrophic myocardiopathy are accompanied with significant changes in the passive mechanical properties and active contractility of myocardium. Identification of these changes helps diagnose heart diseases, monitor therapy, and design surgery. A dynamic cardiac elastography (DCE) framework is developed to assess the anisotropic viscoelastic passive pr...

Blood pressure, heart rate, rate pressure product, heart rate variability, stroke volume, cardiac output, peripheral resistance, and cardiac contractility derived from impedance cardiography were obtained from 15 young and 15 old males during and after the Stroop task. The old group demonstrated significantly higher absolute heart rate, systolic and mean arterial pressure, peripheral resistance...

BACKGROUND Reductions in heart rate (HR) with beta-blocker therapy have been associated with improvements in ejection fraction (EF). However, the relative contributions of HR reduction, positive inotropism, afterload reduction, and reverse remodeling to improvements in EF are unknown. METHODS AND RESULTS Twenty-nine patients (63+/-12 years old) with New York Heart Association class II-III hea...

RATIONALE One of the physiological mechanisms by which the heart adapts to a rise in blood pressure is by augmenting myocyte stretch-mediated intracellular calcium, with a subsequent increase in contractility. This slow force response was first described over a century ago and has long been considered compensatory, but its underlying mechanisms and link to chronic adaptations remain uncertain. ...

Systolic heart failure with reduced ejection fraction has long been regarded as a heart with an irreversible depression in myocardial contractility. Improvements in ventricular function with recovery of contractility, however, have occurred during a period of cardiac unloading provided by a continuous-flow left ventricular assist device. The authors briefly review subcellular remodelling involv...

The shape of the end-systolic tension-length relationship (ESTLR) changes when contractile state is changed, whereas the end-systolic pressure-volume relationship (ESPVR) remains linear despite changes in contractility. To investigate this disparity, the ESPVR was determined with contractility altered extensively by dobutamine, BAY K 8644, nifedipine, lowering coronary blood flow, and the intro...

The effects of electrical stimulation of the vagus nerves have been studied in anaesthetized dogs, before and after bilateral interruption of the cardiac sympathetic nerves. During constant heart rates, maintained by right atrial pacing, vagus nerve stimulation caused small but significant reductions of myocardial contractility, but these were minor compared with the effects of other negative i...