Acquired Annular Sub-valvular Aneurysm Complicated by a Fistulous Tract

Abstract

Background: Left ventricular subvalvular aneurysms (SVA) are rare cardiac anomalies, primarily reported in patients of African descent. They are often classified as subaortic or submitral aneurysms, with the latter being more common. The etiology is speculated to be congenital, though recent cases in non-African patients challenge this notion. We present a case of a Caucasian woman with a submitral aneurysm complicated by an intracardiac fistula. Case: A 60-year-old woman with hypertrophic cardiomyopathy (HCM) and rheumatoid arthritis (RA) presented with progressive dyspnea, palpitations, and chest pressure over six months. A prior cardiac MRI showed only ventricular septal hypertrophy. Transthoracic echocardiography (TTE) revealed severe mitral regurgitation and left ventricular hypertrophy. Right heart catheterization showed elevated right-sided pressures (RA: 22 mmHg, RV: 80/4 mmHg, PA mean: 51 mmHg), while left heart catheterization demonstrated normal coronary arteries. Transesophageal echocardiography (TEE) identified an abnormal left atrium-left ventricle (LA-LV) connection, later confirmed as a submitral pseudoaneurysm. Cardiac MRI revealed a 4.5 × 3.5 × 3.0 cm blood-filled cavity in the left AV groove with fistulous connections to the LA and LV. The patient underwent septal myectomy, mitral valve repair with a 29-mm prosthetic valve, and closure of the LA-LV fistula and pseudoaneurysm with a bovine pericardium patch. She recovered well but had residual pulmonary hypertension and right ventricular dysfunction. Conclusion: This case highlights the diagnostic challenges of SVA in non-African patients. Advanced imaging played a crucial role in diagnosis and surgical planning. Further research is needed to explore links between SVA, HCM, and autoimmune conditions.