Case Presentation: A 64-year-old male with a history of mitral valve prolapse (MVP) presented with palpitations that began the evening before admission. He had similar episodes three weeks prior that resolved spontaneously. Diagnosed with MVP in 2022 via transthoracic echocardiogram (TTE) after experiencing palpitations and shortness of breath, he underwent multiple echocardiograms and EKGs. In 2023, a transesophageal echocardiogram (TEE) revealed severe mitral regurgitation (MR) from prolapse. Despite these findings, he was hesitant about valve repair surgery as the symptoms were not disruptive to his daily activities. During the current admission, an EKG showed atrial fibrillation with rapid ventricular response (RVR), a new finding for him. He has a family history of atrial fibrillation in his mother and maternal grandmother. He was treated with a Cardizem drip, therapeutic lovenox, and metoprolol, and spontaneously converted to normal sinus rhythm on the second day. A TTE showed EF 60-65% with grade II diastolic dysfunction and moderate to severe MR with an anteromedial eccentrically directed jet. A subsequent TEE revealed severe MR with an anterior mitral valve cleft and posterior leaflet prolapse with flail. After discussing the findings and the importance of valve repair, the patient decided to proceed with surgical intervention. He was discharged on metoprolol succinate 50 mg daily and apixaban 5 mg twice daily, along with his original home medications.
Discussion: An isolated anterior mitral valve leaflet cleft is a rare congenital structural anomaly that can often go undiagnosed for most of an individual’s lifetime. Typically, this anomaly is seen alongside other congenital cardiac defects. However, when it occurs in isolation, it is extremely rare and is usually diagnosed only when patients begin to develop symptoms that lead to further cardiac evaluation.
Conclusions: This case highlights a rare congenital anterior mitral valve leaflet cleft discovered incidentally in a patient with new-onset atrial fibrillation. Despite extensive cardiac workup over two years, prior imaging did not reveal this anomaly. This finding underscores the importance of considering rare congenital defects in patient education and management to optimize health outcomes.