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Biomedical subjects

E F Blick

Publications and source records attributed to E F Blick.

18 recordsLinked to original sources
PubMed1980

Effect of turbulent blood flow on systolic pressure contour in the ventricles and great vessels: significance related to anacrotic and bisferious pulses.

The effect of turbulent blood flow on the contour of systolic pressure in the left and right ventricles and great vessels was investigated in 64 patients undergoing diagnostic cardiac catheterization. Intracardiac pressure and sound were recorded using a catheter-tip micromanometer. Measurements were made in normal subjects and patients with a variety of disorders including aortic stenosis, hypertrophic obstructive cardiomyopathy, coarctation of the aorta and atrial septal defect. Observations showed a consistent association of the intracardiac murmur, which is indicative of turbulence, with a transient reduction of the centrally recorded systolic pressure. The resultant abnormal systolic pressure contour can be explained on the basis of fluid dynamic considerations related to turbulence.

Aorta↗
PubMed1980

Comparison of the distribution of intramyocardial pressure across the canine left ventricular wall in the beating heart during diastole and in the arrested heart. Evidence of epicardial muscle tone during diastole.

Computations of compliance of the left ventricle (LV) during diastole assume passive tissue characteristics. To evaluate this assumption, we measured diastolic LV intramyocardial pressure simultaneously in the subepicardium and subendocardium in 18 open-chest dogs, using 1-mm in diameter micromanometers. Subepicardial pressure, 26 +/- 1 mm Hg (mean +/- SEM) exceeded subendocardial pressure, 14 +/- 1 mm Hg (P less than 0.001), and it exceeded left ventricular end-diastolic pressure (LVEDP) (9 +/- 1 mm Hg) (P less than 0.001). After an infusion of dextran-40 (10 dogs), subepicardial diastolic pressure increased to 42 +/- 4 mm Hg which was higher than diastolic subendocardial pressure, 26 +/- 2 mm Hg (P less than 0.001) and LVEDP, 24 +/- 2 mm Hg (P less than 0.001). Following cardiac arrest (12 dogs) with the intramyocardial probes unchanged in position, LV intracavitary pressure, 9 +/- 1 mm Hg, and subendocardial pressure, 13 +/- 3 mm Hg, did not differ significantly from the pressures in the beating heart. Subepicardial pressure, 9 +/- 1 mm Hg, was lower than in the beating heart (P less than 0.001). Following distention of the arrested LV (12 dogs), subepicardial pressure, 31 +/- 7 mm Hg, was lower than both subendocardial pressure, 58 +/- 12 mm Hg (P less than 0.001) and LV intracavitary pressure, 54 +/- 11 mm Hg (P less than 0.001). These observations indicate that tone is maintained by the subepicardium during diastole. Furthermore, the LV wall does not appear to behave as a passive shell during ventricular filling.

Animals↗
PubMed1977

Effects of structural configuration of prosthetic aortic valves upon coronary blood flow.

This study was performed in order to determine the effects of the structural configuration of prosthetic aortic valves upon coronary blood flow. A pulse-duplicating system was utilized to which a rigid model of the root of the aorta and the left artery were attached. A stented normal human valve, stented porcine valve, pivoting disc valve, tilting disc value and a caged ball valve were tested at stimulated resting conditions. The results showed that the pulse configuration and proportions of coronary flow that were systolic and diastolic changed with various valves. There was no significant reduction of the mean simulated coronary flow with the porcine valve or disc valves. Coronary flow was augmented with the caged ball valve. These differences were interpreted as being due to several fluid dynamic phenomena. These were piston effects, inertia of reversed blood flow, torque and the effects resulting from the unique pressure distribution on each valve.

Aortic Valve↗