With improvements in technology, operative technique, and critical care medicine, more and more children with congenital heart disease are surviving into adulthood. As they age, these patients are providing physicians with new challenges, and we are realizing the long-term consequences of our previous interventions. This oftentimes has changed the mode of treatment for subsequent children. Response by Khairy and Poirier on p 2515 Fontan palliation for single-ventricle patients was first described in 1971.1 The original approach was in the form of a classic atriopulmonary Fontan connection, bypassing the nonfunctional right ventricle. After recognizing the long-term complication of an atriopulmonary connection (right atrial dilation, arrhythmias, and thrombus formation), modifications have been made. The atriopulmonary connection has been abandoned in favor of modified Fontan anatomy and physiology. The modified Fontan can be performed by the use of an extracardiac conduit approach or a lateral tunnel approach. The extracardiac Fontan uses an external conduit to anastomose the inferior vena cava into the pulmonary arteries, whereas a lateral tunnel Fontan uses a baffle within the right atrium (Figure 1). Because the systemic venous pathway is completely separated from the right atrium with the extracardiac Fontan, it is more challenging for the electrophysiologist to access the heart for ablation. My aim is to demonstrate why “the extracardiac conduit is the preferred Fontan approach for patients with univentricular hearts.” Figure 1. Left , Lateral tunnel Fontan shows the Fontan pathway inside of the right atrium. Right , Extracardiac Fontan shows the conduit completely separated from the right atrium. The extracardiac Fontan has several advantages over the lateral tunnel Fontan. Minimizing cardiopulmonary bypass and ischemia may optimize early postoperative outcomes. In multiple studies, both prolonged cardioplegic arrest and extended cardiopulmonary bypass times have been associated with an increased risk of early postoperative death or Fontan failure.2– …