Membranous Interventricular Septal Aneurysm. A Case Report

Aneurysmal formation in the membranous part of the interventricular septum is a very rare heart defect. The interventricular membranous septal (IVMS) aneurysm is mainly found in conjunction with ventricular septal defects or other congenital cardiac anomalies. It has often been found as an asymptomatic phenomenon, so that it is diagnosed incidentally during imaging evaluations of heart structures. Thereby, its presence without other congenital cardiac anomalies is a very uncommon entity. Herein, we describe a 77-year-old man with the chief complaints of chest pain and dyspnea on exertion. The physical examination was normal except for the presence of ejection-type systolic murmurs along the left sternal border in the aortic area on auscultation. The patient's preoperative transthoracic echocardiography revealed severe aortic valve stenosis, and his transesophageal echocardiography during aortic valve replacement revealed an incidental IVMS aneurysm. The aneurysm was resected concomitantly with aortic valve replacement surgery, and he was asymptomatic and stable in the follow-up period.