Electrical dyssynchrony leads to prestretch in late-activated regions and alters the sequence of mechanical contraction, although prestretch and its mechanisms are not well defined in the failing heart. We hypothesized that in heart failure, fiber prestretch magnitude increases with the amount of early-activated tissue and results in increased end-systolic strains, possibly due to length-depend...

Alongside the remarkable advances in medical and invasive therapies for the treatment of ischemic heart disease, an increasing number of patients with advanced coronary artery disease unsuitable for revascularization continue to suffer from angina pectoris despite optimal medical therapy. Patients with chronic angina have poor quality of life and increased levels of anxiety and depression. A co...

BACKGROUND Left ventricular (LV) energy supply-demand imbalance is postulated to cause "energy starvation" and contribute to heart failure (HF) in nonischemic dilated cardiomyopathy (NIDCM). Using cardiac magnetic resonance (CMR) and [(11)C] acetate positron emission tomography (PET), we evaluated LV perfusion and oxidative metabolism in NIDCM and the effects of spironolactone on LV supply-dema...

With aging, structural and functional changes occur in the myocardium without obvious impairment of systolic LV function. Transmural differences in myocardial vulnerability for these changes may result in increase of transmural inhomogeneity in contractile myofiber function. Subendocardial fibrosis and impairment of subendocardial perfusion due to hypertension might change the transmural distri...

Wu et al1 found that the titin isoforms N2BA/N2B ratio was decreased from a normal ratio of 1.0 to 0.8 in the paced dog heart. Because N2B represents the isoform with stiffer elastic properties, this resulted in an increased passive stiffness in isolated muscle strips. The authors suggest that this “titin-based” stiffness is acting in concert with “collagenbased” stiffness and that it may count...

We developed a new ultrasonic triangulation technique to measure regional wall thickness and shear motion of the left ventricular wall under normal conditions and during complete and partial coronary occlusions. In 10 open-chest dogs, a left ventricular micromanometer was inserted, and a screw-driven arterial clamp and flowmeter were placed around the left circumflex coronary artery. A single m...

Simvastatin (SIM) is a lipid-soluble inhibitor of hydroxy-3-methylglutaryl coenzyme A reductase with multiple reported therapeutic benefits. The present study was designed to investigate the effect of pretreatment with SIM on isoproterenol (ISO)-induced cardiac hypertrophy in rats. Twenty-four male albino Wistar rats weighing 180-200 g were divided into four groups. Groups I and III received no...

BACKGROUND AND OBJECTIVES Patients with sickle cell disease (SCD) have multi-organ manifestations of microvascular disease, though cardiac manifestations have been poorly characterized in vivo. This study sought to characterize myocardial characteristics in adult patients with SCD. DESIGN AND METHODS Twenty-two consecutive outpatients and 11 age-matched controls underwent magnetic resonance i...

A newly designed balloon coronary angioplasty catheter that allows passive antegrade blood flow during balloon inflation (autoperfusion catheter) was compared with a standard balloon coronary angioplasty catheter. In a randomized sequence, inflations were performed for 3 min in the left circumflex coronary artery of 12 dogs with the standard catheter followed by the autoperfusion catheter or vi...

The resistance to coronary blood flow in various parts of the myocardium was studied with the tracer microspheres technique before and immediately after an acute coronary occlusion and several weeks after a more slowly occurring coronary occlusion by Ameroid constrictor. All experiments were carried out in the isolated, metabolically supported, empty, beating dog heart at maximal coronary vasod...