VENTRICULAR-FUNCTION IN THE SINGLE VENTRICLE BEFORE AND AFTER FONTAN SURGERY

To better delineate the importance of ventricular function in patients with a single ventricle and assess its relation to outcome after the Fontan procedure, 47 patients with a single ventricle were studied. Ventricular ejection fraction was estimated by radionuclide angiocardiography. Before Fontan surgery, ejection fraction was 0.57 +/- 0.10 (mean +/- standard deviation). This differed significantly from the normal mean left ventricular ejection fraction of 0.68 +/- 0.09 (p < 0.001) derived in our laboratory by radionuclide angiocardiographic methods. Age, ventricular morphology and the presence of pulmonary artery band or systemic to pulmonary artery shunts had no statistical relation to ventricular ejection fraction in patients with a single ventricle. Serial preoperative evaluation in 15 patients over 3.8 +/- 1.3 years revealed no significant change in ventricular ejection fraction; however, increased atrioventricular valve regurgitation was documented in 4 of these 15. Modified Fontan procedure was performed in 24 of the 47 study patients; 7 have died, 1 has undergone cardiac transplantation and 1 faces possible transplantation. No difference was noted in preoperative ejection fraction between survivors and nonsurvivors. Ventricular morphology, age at Fontan surgery and operative factors such as bypass and cross-clamp time were not related to functional outcome. Preoperative ejection fraction of 0.52 +/- 0.08 decreased to 0.39 +/- 0.11 (p < 0.001) when evaluated 1.16 +/- 0.44 years after Fontan surgery. In patients with a single ventricle (1) ventricular ejection fraction is less than that of the normal systemic ventricle; (2) during childhood, ejection fraction is not related to age or ventricular morphology; and (3) ventricular ejection fraction frequently decreases after a Fontan repair. Thus, long-term studies of clinical course and ventricular function are essential before altering recommendations for pursuing the Fontan repair.