Atrioventricular Septum Pseudoaneurysm As Late Complication After Repeated Mitral Valve Replacement.

We report the case of a pulsatile mass found in a patient who presented for a routine echocardiogram. The mass turned out to be an exceedingly rare mitral-subannular pseudoaneurysm involving the membranous atrioventricular septum with systolic expansion protruding into right atrium, discovered late after repeated multiple valve replacement surgery. Although these pseudoaneurysms may present asymptomatically, surgical intervention might be indicated because of the risk of rupture. This report describes this rare finding, discusses possible pathophysiological mechanisms, and underscores the importance of multimodality imaging to achieve correct identification and delimitation to guide surgical intervention in such cases.