To test the hypothesis that the fall in supravalvular aortic diastolic pressure is relative to the severity of the regurgitant flow in aortic regurgitation, 27 patients with isolated aortic regurgitation, 23 patients with combined aortic regurgitation and stenosis, and 15 normal subjects were studied. Diastolic pulse pressure (pressure at the dicrotic notch minus pressure at end diastole) and t...

This study was performed to examine the transmural (endocardial vs. epicardial) heterogeneity of myocardial blood flow during the cardiac cycle (systole vs. diastole). Twenty-four contrast echocardiographic injections were performed in seven open-chest anesthetized dogs either into left anterior descending or circumflex coronary artery or into the aortic root. Two-dimensional echocardiography i...

Aortic valve leaflets undergo extraordinary flexion due to the complete reversal of their curvature during billions of cardiac cycles. The flexion stresses in the leaflet depend on its elastic modulus which we investigated in vivo and in vitro. In six dogs, we placed radiopaque markers on an aortic leaflet. Leaflet length was calculated from the marker positions recorded fluoroscopically. Aorti...

The following true/false questions may be attempted before reading the tutorial. The answers are given at the end of the text. 1. In the normal heart: a. Pre-load is the same as left ventricular end-diastolic volume b. Increase in pre-load has no effect on the force of the next contraction c. Systemic vasoconstriction reduces afterload d. Isovolumetric ventricular contraction ends when the aort...

Previous studies from our laboratory have shown that the position of the ventricular septum relative to the two ventricles at end-diastole is determined by the instantaneous transseptal pressure gradient (TSG) defined as left ventricular minus simultaneous right ventricular pressure. Since patients with mitral stenosis often have exaggerated leftward (paradoxic) motion of the ventricular septum...

Systolic left ventricular (LV) gradients and diastolic dysfunction are widely studied in hypertrophic cardiomyopathy (HCM) [1,2], however diastolic gradients have never been described. A patient with HCM, mid-cavity obliteration and apical aneurysm, diagnosed by both 2D echocardiography (Fig. 1, panel A) and cardiac magnetic resonance (Fig. 1, panel B), showed color Doppler aliasing effect at m...

Fiber orientation across the left ventricular myocardial wall has been studied. Specimens were obtained from 18 dog hearts rapidly fixed in situ in systole, in diastole, and in dilated diastole. Fiber orientation was determined across the free wall at eight sites from a T-shaped specimen by measurements with light microscopy in serial paraffin sections. Results indicate: (1) The wall has a well...