Biventricular Conversion of Single Ventricle: Adopting the Left Ventricle as the Systemic Pump

Abstract

Single-ventricle (SV) palliation of neonates with either moderately hypoplastic left ventricle (LV) or complex intracardiac routing anatomy is frequently chosen as an initial step to facilitate survival out of the newborn period. In the case of borderline left heart structures, uncertainty around the adequacy of LV often continues, leading to further progression on the SV pathway with bidirectional cavopulmonary shunt and eventual Fontan despite the presence of a descent second ventricle. Similarly, SV pathway also continues beyond the neonatal period in those patients in whom intracardiac routing is deemed “too complex” in infancy. Frequently, this initial commitment to the SV pathway is never reconsidered later in life and never reversed, leaving the patient with SV physiology. Thus, these patients are continuously subjected to the detrimental effects of SV circulation despite having the presence of 2 ventricles. Some of these patients, however, can be reconsidered for biventricular (BV) conversion at a later stage via either a 2-ventricle or a one-and-a-half-ventricle circulation. We present 2 examples of patients with different anatomical lesions who were initially managed in an SV pathway and highlight the different surgical techniques employed to achieve either a 2 or a one-and-a-half-ventricle conversion from a Fontan circulation.