Asymmetric distribution of left ventricular asynergy in coronary artery disease and its relation to coronary stenoses

Abstract

In 100 patients with coronary artery disease (CAD), the prevalence and severity of asynergy was determined for 9 left ventricular (LV) segments by both radionuclide and contrast anglography. The anterior, septal and lateral LV walls had significantly more prevalent and more severe asynergy in the medial segments than in the basal segments. In contrast, the inferior LV wall exhibited equally severe asynergy in both the medial and basal segments. In general, asynergy was most severe in the apical, medial septal, medial inferior and basal inferior LV segments. This asymmetric distribution of LV asynergy could not be explained by the distribution of occlusions or significant stenoses in the arterial tree, which were relatively uniformly distributed among the left anterior descending (32%), left circumflex (29%) and right (26%) coronary arteries. It is postulated instead that the asymmetric distribution of LV asynergy results from asymmetry of the coronary arterial tree supplying the left ventricle and that the prevalence of asynergy in an LV segment is directly related to its vascular distance from the coronary ostia. Unlike the relatively direct supply of the left anterior descending and circumflex arteries to the basal segments of the anterior, septal and lateral LV walls, the arterial supply to the basal inferior wall begins only after the right or dominant circumflex artery has traversed the length of the atrioventricular groove, significantly increasing its susceptibility to the pressure attenuation and occlusive jeopardy of more proximal stenoses.