ACUTE CHANGES IN PRELOAD, AFTERLOAD, AND SYSTOLIC FUNCTION AFTER SUPERIOR CAVOPULMONARY CONNECTION

Background. Superior cavopulmonary connection reduces the volume work of the single ventricle. Methods. To determine the effects of superior cavopulmonary connection on preload, wall stress (or afterload), and systolic ventricular function, we studied 9 patients before and after operation, and at hospital discharge. Using echocardiography, preload was estimated by the ventricular end-diastolic area, and wall stress w as calculated at end-systole and peak-systole. Ventricular function wa s represented by rate-corrected velocity of circumferential fiber shor tening and fractional area change divided by rate-corrected ejection t ime. Results. End-diastolic area and wall stress decreased postoperati vely. Ventricular wall thickness increased with a concomitant decrease in cavity area. There was no change in mean blood pressure or heart r ate or in rate-corrected velocity of circumferential fiber shortening or fractional area change divided by rate-corrected ejection time. The se findings persisted at hospital discharge. Conclusions. In single ve ntricles, superior cavopulmonary correction results in an immediate de crease in preload and afterload. The decrease in afterload results pri marily from alterations in ventricular geometry. Although no improveme nt in systolic function was noted, diminished work related to the redu ction in loading conditions may have beneficial long-term effects on p reserving myocardial performance. (C) 1998 by The Society of Thoracic Surgeons.