ASSESSMENT OF A NEW VENTRICULAR CONTRACTILE INDEX OBTAINED WITH TRANSESOPHAGEAL ECHOCARDIOGRAPHY BEFORE AND AFTER CARDIOPULMONARY BYPASS INCARDIAC SURGICAL PATIENTS

We have compared a new contractile index ''left ventricular end-systol ic wall stress-heart rate-corrected velocity of circumferential fibre shortening (vcfc)'' with conventional contractile indices in 13 patien ts 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 a rterial pressure before and after cardiopulmonary bypass (CPB). In all patients, significant correlations were obtained for end-systolic wal l stress-area and peak arterial pressure-area relationships before and after CPB. In all patients, significant inverse linear correlations w ere 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 mechanis m of loss of the inverse linear correlation in the end-systolic wall s tress-vcfc relationship.