MORPHOLOGY OF HEARTS UNDERGOING FONTAN REPAIR

Background - Notwithstanding the controversies evoked by the term ''si ngle ventricle'', most patients with this condition would undergo the Fontan procedure. In addition, there is a large group of patients in w hom a biventricular repair would be abandoned in favour of a univentri cular one because of the presence of unfavourable morphologic features . There is a need for a uniformly acceptable system of nomenclature th at would permit precise description and classification of hearts with complex malformations to facilitate reporting and help in understandin g the reasons for choosing a univentricular repair. Methods - Echocard iographic, angiographic and operative records of 240 patients undergoi ng the Fontan procedure were analysed. Results - Out of the 104 patien ts with univentricular atrioventricular connections, 2 ventricles were discernible in all but 3 patients. A Fontan repair was performed in 1 36 patients with biventricular atrioventricular connections because of the presence of a hypoplastic ventricle in 52 patients and a non-comm itted ventricular septal defect in the remaining 84. Conclusions - The Fontan operation is probably the only definitive treatment option for patients with univentricular atrioventricular connections. The decisi on to perform a univentricular repair in preference to a biventricular one in hearts with biventricular atrioventricular connections is base d on the presence of a hypoplastic ventricle or a non-reroutable ventr icular septal defect. This decision is subjective. In hearts with disc ordant atrioventricular connections and pulmonary stenosis, we prefer the Fontan operation to the classical repair.