Neonatal physiology of the functionally univentricular heart

Abstract

The term “functionally single ventricle” includes a variety of congenital cardiac anomalies where there is only one ventricle pumping blood to the systemic and pulmonary circulations. The physiology in this arrangement is a considerable challenge for the cardiac specialist, because the complexity encountered in patients with these lesions necessitates particularly specialized medical and surgical management. Patients with such functionally univentricular physiology often respond to common interventions, such as supplemental oxygen, mechanical ventilation, and vasoactive drugs, differently than patients with conventional circulations.1 Furthermore, these patients tend to be encountered more frequently by pediatricians and cardiologists because they undergo multiple operations, may be more adversely affected by intercurrent illnesses, or have chronic cardiac problems requiring frequent attention. A thorough understanding of the complexities of the physiology encountered is thus imperative for the pediatric cardiologist. In this review, we will address important physiologic and anatomic principles that influence care of neonates with functionally univentricular hearts. Although the anatomy and physiology of each reconstructive stage of palliation are unique, we will focus upon the pre- and post-operative physiology as encountered in the neonate.