Abstract 12766: Dissection of the Interventricular Septum: Echocardiographic Features

Abstract

Objective: Dissection of the interventricular septum (IVS) is an extremely rare entity. An institutional data base review identified 13 pts with the diagnosis, confirmed by cardiac surgery. The purpose of the study was to determine the value of transthoracic echocardiography (TTE) in establishing the diagnosis and to summarize the TTE features of IVS dissection. Methods: The 13 pts with IVS dissection, 8 males and 5 females (age range: 36-75 yrs) were taken from 789,114 TTEs performed between 1985 and 2014. The etiology, anatomical location, echocardiographic morphology, and color Doppler findings of the IVS dissection were noted. Results: The incidence of IVS dissection in our center was 0.000016 %. Among 13 patients with IVS dissection, the right sinus of Valsalva (RSOV) was involved in 11 pts. In 5 pts, a single aneurysm of the RSOV dissected into the IVS. In 4 pts, aortic valve (AoV) endocarditis was associated with the IVS dissection, including one pt with a bicuspid AoV infection, 2 pts with absess formation adjacent to an AoV replacement, one pt. with a combination of a bicuspid AoV and RSOV dissecting into the IVS, and one pt with an AoV prosthetic paravalvular leak following absess formation dissecting into the IVS. In one patient, a bicuspid AoV valve combined with RSOV dissected into the IVS. Also, in one pt, mechanical AoV prosthetic replacement was complicated by annular detachment and a severe paravalvular leak. In all 11 pts with RSOV involvement, TTE showed a dissecting cystic-like mass in the IVS from the base to mid-septum or confined to the septal base. The path of the dissection in all these pts was traced to the RSOV. Also, communications between the dissection and the aortic root were seen in these 11 patients. In the other 2 pts, IVS dissection followed septal rupture due to a myocardial infarction. In these pts, communication between the dissection and the right ventricle was seen. Conclusions: The study showed that dissections of the IVS usually commenced in the RSOV, due to either congenital anomalies or infective endocarditis, or following AoV replacement. The other cause of IVS dissection is a myocardial infarction. The TTE characteristic of IVS dissection is a cystic-like mass in the IVS.