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J K Alexander

Publications and source records attributed to J K Alexander.

88 records · Page 5Linked to original sources
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Determination of the time course of left ventricular wall stress and velocity of fiber shortening in man by simultaneous left ventricular pressure and echocardiographic recording: preliminary report.

This report presents a method for determining the time course of circumferential LV wall stress and fiber shortening velocity (endocardial as well as midwall) using simultaneous recordings of LV dimensions by echography and LV pressure (micromanometer). The values for max VCF, VCF at peak stress, mean VCF, and peak stress are in general agreement with those observed with previous methods; the separation between normal and abnormal LV function appears to be good. The method permits frequent observations to be performed in a single patient, which is of particular value during acute interventions. Data from a small number of interventions suggest that VCF in man is relatively insensitive to acute changes in preload, is inversely affected by changes in afterload and appears sensitive to inotropic stimulation. Although VCF seems to be a good index of LV performance, its sensitivity to afterload might, at times, limit its usefulness.

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Pulmonary vascular complications in narcotic addicts.

Perfusion deficits on lung scanning in narcotic addicts are frequently demonstrable. To determine the angiographic and hemodynamic correlates of these deficits, right heart catheterization with selective pulmonary angiography was carried out in 7 addicts with abnormal lung scans, and one with normal scan. Four had angiographic abnormalities corresponding to the regions of perfusion defects on lung scan. These consisted of large vessel cut-offs, intraluminal filling defects and/or considerably reduced vascularity. Three subjects had normal angiograms in the presence of abnormal perfusion scans. One subject had normal angiogram and scan. All eight patients had normal pulmonary artery pressures and calculated pulmonary vascular resistances. This study demonstrates that (1) angiographic abnormalities in larger pulmonary arteries may be found in narcotic addicts with perfusion defects on lung scanning, and (2) these findings may be present without significant hemodynamic alterations.

Adult↗