Diagnosis of congenital and acquired Gerbode defects by cardiac MRI: two cases.

The Gerbode defect is a rare left ventricle-to-right atrium shunt, often misdiagnosed as tricuspid regurgitation, and may be either congenital or acquired. We report two cases: one acquired Gerbode defect following redo mechanical mitral valve replacement surgery, presenting with dyspnea and progressive heart failure; and one incidental congenital Gerbode defect in an asymptomatic patient. In both cases, Cardiac Magnetic Resonance (CMR) clarified shunt anatomy and informed management decisions. The first patient underwent successful percutaneous closure under Digital Subtraction Angiography (DSA), while the second received conservative follow-up due to the absence of symptoms. CMR complemented echocardiography by delineating anatomical features, particularly when acoustic windows were limited, and supported post-treatment evaluation.