Fundamental questions in the mechanics of the right ventricle (RV) include: what are the distributions of diastolic and systolic strains across the RV epicardium and how do these strains change with increasing preload? Arrays (approximately 4 x 4 cm) of 25 to 30 lead markers were sutured to the epicardium of the RV anterior free wall in 6 open-chest, anesthetized dogs. Biplane cinéradiography (...

The purpose of this study was to test the hypothesis that acute disruption of fibrillar collagen will decrease myocardial systolic performance without changing cardiomyocyte contractility. Isolated papillary muscles were treated either with plasmin (0.64 U/ml, 240 min) or untreated and served as same animal control. Plasmin treatment caused matrix metalloproteinase activation and collagen degra...

Left ventricular (LV) diastolic dysfunction often occurs in patients with type 2 diabetes mellitus (DM) independent of atherosclerotic coronary artery disease, myocardial ischemia, and regional wall motion anomalies. Limited information exists on LV myocardial tissue strain in this patient group. We measured 3-dimensional (3-D) parameters of LV systolic and diastolic functions in 28 patients wh...

The pattern of myocardial segment length change in an ischemic and nonischemic area of the left ventricle was studied acutely following ligation of the LADA in the dog. Results were interpreted in relation to other hemodynamic findings obtained in the same experiments. Paradoxical bulging during systole was found in the ischemic area, whereas increased shortening during systole was found in the...

The purposes of this study were to assess load-independent, end-systolic relationships in mice and compare these relationships to ejection phase indexes in assessing contractility. In 13 mice, ejection phase indexes (shortening fraction and velocity of fiber shortening) and end-systolic relationships [pressure-dimension relationship (ESPDR) and stress-velocity relationship (ESSVR)] were determi...

The effects of intracoronary (IC) nitroglycerin (NTG) on left ventricular (LV) function were evaluated in 13 patients with significant coronary artery disease. LV cineangiograms were performed in the 40° right anterior oblique projection before and 2 minutes after 0.15 mg NTG was injected directly into the left main coronary artery, and angiographically derived volume and dimensional data were ...

Nineteen patients with chronic aortic regurgitation and a large increase in heart size were studied before aortic valve replacement. By relating midwall circumferential systolic stress to midwall circumferential fibre shortening (Cs/Cd) before operation the patients could be divided into two well defined groups. Twelve patients (group 1) had a pronounced decrease in heart size as measured by th...

The isovolumic index is the ratio of the duration of isovolumic contraction (IVC) and relaxation (IVR) divided by ejection time (ET), and has been proposed as a more sensitive descriptor of ventricular performance than the systolic time index, which ignores the period of isovolumic relaxation. To determine the effects of acute ischemia on these indices, IVC, IVR, and ET were measured in seven o...

In a "physiologically sequenced" contraction (PSC), which loads the isolated muscle preparation in a manner which approximates that of the intact heart, isometric relaxation precedes isotonic relaxation and occurs at minimum ("end-systolic") length. We studied the effects of inital muscle length, load, temperature, calcium, and isoproterenol on the isometric relaxation phase of physiologically ...

BACKGROUND Many asymptomatic patients with aorta regurgitation and normal left ventricular systolic function remain clinically stable for many years, but others ultimately develop symptoms or left ventricular dysfunction and require operation. To identify indexes of left ventricular function predictive of symptomatic and functional deterioration during the long-term course of asymptomatic patie...