Pulmonary hypertension and mitral regurgitation in an infant with an anatomically normal mitral valve.

A full-term, female presented on her date of birth with severe pulmonary hypertension (PH) and mitral regurgitation (MR), requiring veno-arterial extracorporeal membrane oxygenation. After the treatment, her PH and MR were resolved with no anatomic abnormality present. We propose a positive feedback loop of PH causing right ventricular dilation and interventricular septal shifts, worsening MR, and elevated left atrial, and potentially pulmonary, pressures.