Assessment of a new ventricular contractile index obtained with transoesophageal echocardiography before and after cardiopulmonary bypass in cardiac surgical patients.

Abstract

We have compared a new contractile index "left ventricular end-systolic wall stress-heart rate-corrected velocity of circumferential fibre shortening (vcfc)" with conventional contractile indices in 13 patients undergoing coronary artery bypass grafting. We generated the slopes of the "end-systolic wall stress-vcfc", "end-systolic wall stress-area" and "peak arterial pressure-area" relationships by altering arterial pressure before and after cardiopulmonary bypass (CPB). In all patients, significant correlations were obtained for end-systolic wall stress-area and peak arterial pressure-area relationships before and after CPB. In all patients, significant inverse linear correlations were obtained for the end-systolic wall stress-vcfc relationship before CPB; however, inverse linear correlation was absent in eight patients after CPB. It may be that the increased afterload had less influence on left ventricular systolic function after CPB as a possible mechanism of loss of the inverse linear correlation in the end-systolic wall stress-vcfc relationship.