Refractory Postcardiotomy Right Ventricular Failure Revealing Massive Right Ventricular Lipomatous Replacement:...

Right ventricular (RV) fat may represent benign lipomatosis, postischemic metaplasia, or arrhythmogenic right ventricular cardiomyopathy (ARVC); distinguishing them is difficult yet clinically relevant.

A 76-year-old woman with severe degenerative mitral regurgitation underwent elective valve repair. Preoperative echocardiography and cardiac magnetic resonance showed preserved biventricular function without abnormal intramyocardial fat on standard sequences. After cardiopulmonary bypass, refractory RV failure ensued despite optimized loading, inhaled vasodilators, inotropes, temporary RV support, and venoarterial extracorporeal membrane oxygenation. Coronary angiography excluded culprit lesions. She died on postoperative day 15. Autopsy revealed diffuse RV lipomatous replacement with a thin residual myocardial layer.

Extensive RV adipose replacement may impair contractile reserve and present as refractory postcardiotomy RV failure despite "normal" preoperative imaging, with morphological overlap with ARVC and postischemic metaplasia.

In unexplained postcardiotomy RV failure, consider preexisting lipomatous RV replacement. Standard preoperative imaging without dedicated fat-water sequences may be falsely reassuring.