Geometric and functional abnormalities of the left ventricle with a chronic localized noncontractile area

Abstract

Thirty-one patients with coronary artery disease, 25 of whom had a chronic localized noncontractile area in the anteroapical region of the left ventricle, were studied at rest by means of left heart catheterization, left cineventriculography and selective coronary arteriography. The left ventricular volume, stroke volume, ejection fraction, left ventricular end-diastolic pressure, cardiac output and the surface area of the noncontractile area were measured. The patients with a noncontractile area were classified in 4 groups according to the size of the noncontractile area relative to the end-diastolic left ventricular surface area. The relative size of the non-contractile area ranged from 5 to 47 percent. Six patients with uncomplicated coronary artery disease comprised the control group. The critical size of the noncontractile area beyond which significant functional derangement occurred appeared to be 20 to 30 percent of the left ventricular internal surface area. The end-diastolic volume increased significantly and the ejection fraction was reduced to less than half of normal when the regional noncontractile area was larger than the critical size. Neither the cardiac output nor the left ventricular end-diastolic pressure correlated closely with size of the noncontractile area. In contrast, the ejection fraction was a more sensitive indicator and correlated well with the extent of regional contraction abnormality. In this study, double vessel disease was most common, followed by single vessel disease. Obstruction of the left anterior descending coronary artery was significant in the formation of anteroapical noncontractile regions.