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 was calculated at end-systole and peak-systole. Ventricular function was represented by rate-corrected velocity of circumferential fiber shortening and fractional area change divided by rate-corrected ejection time. Results. End-diastolic area and wall stress decreased postoperatively. Ventricular wall thickness increased with a concomitant decrease in cavity area. There was no change in mean blood pressure or heart rate or in rate-corrected velocity of circumferential fiber shortening or fractional area change divided by rate-corrected ejection time. These findings persisted at hospital discharge. Conclusions. In single ventricles, superior cavopulmonary correction results in an immediate decrease in preload and afterload. The decrease in afterload results primarily from alterations in ventricular geometry. Although no improvement in systolic function was noted, diminished work related to the reduction in loading conditions may have beneficial long-term effects on preserving myocardial performance.