Myocardial Calcification and the Demise of an Infant With Surgically Treated Hypoplastic Left Heart Syndrome

Abstract

A term female infant with hypoplastic left heart syndrome underwent Norwood palliation including aortic and pulmonary amalgamation with arch reconstruction, atrial septectomy, and right ventricle to pulmonary artery conduit. Postoperatively, she experienced hypoxemia and lactic acidosis although echocardiogram showed adequate conduit function. She was placed on veno-arterial extracorporeal membrane oxygenation (ECMO) on postoperative day two with improvement. ECMO decannulation was attempted with subsequent cardiac arrest and ultimate failure to resuscitate, eleven days after surgery. Autopsy confirmed clinical findings and evidence of surgical intervention with a patent conduit and neo-aorta. Multiple subendocardial right ventricular dystrophic calcifications involving the outflow tract were identified grossly and histologically with foci of associated myonecrosis. Myocardial calcification may lead to abnormal heart wall motion by increasing rigidity and compromising myocyte function or compromising the conduction system. In this patient, right ventricular turbulence caused by systolic and diastolic flow patterns, including mild tricuspid regurgitation, may have played a role in inducing dystrophic calcification along with surgery and ECMO dependence. Compromised myocyte function from calcifications, right ventricular hypertrophy, lung immaturity, and persistent pulmonary hypertension were likely sources of cardiac strain leading to the patient’s demise. This case represents a previously unreported complication of hypoplastic left heart syndrome treatment.