CARDIAC ANATOMY IN PATIENTS UNDERGOING THE FONTAN PROCEDURE

Background. Controversies in nomenclature, especially of hearts with ' 'single ventricle,'' have clouded discussion and understanding of the anatomy. Many patients with such malformations are submitted to the Fo ntan procedure as definitive surgical palliation. The spectrum of anat omy among these patients is wide and deserves analysis in an effort to provide a simple framework for description and to eliminate confusion . Methods. We reviewed 138 successive patients undergoing the Fontan o peration at one institution to demonstrate the variability in patholog y. Results. Only 89 patients (65%) had a univentricular type of atriov entricular connection. All but 5 patients had two ventricular chambers . Among the 49 patients with biventricular atrioventricular connection s, 43 had a hypoplastic ventricle that precluded a biventricular repai r. Conclusions. Full understanding of the malformations that may precl ude a ''biventricular'' repair and hence necessitate a Fontan procedur e requires knowledge of: the different forms of univentricular atriove ntricular connection that, although usually associated with two ventri cular chambers, are seldom amenable to a ''two-pump repair.'' Understa nding of those types of ''biventricular heart'' that preclude a two-pu mp repair (eg, severe hypoplasia of the left ventricle or the right ve ntricle) or are associated with high risks (eg, straddling atrioventri cular valve) is also important.