Dissection of the interventricular septum: Echocardiographic features

Abstract

Dissection of the interventricular septum (IVS) is an extremely rare entity. An institutional echocardiographic database was retrospectively reviewed; 13 patients with a diagnosis of IVS dissection were found and confirmed by cardiac surgery. The purposes of the study were: to determine the value of transthoracic echocardiography (TTE) in establishing the diagnosis of IVS dissection, and to detail the TTE features of IVS dissection.Thirteen patients with IVS dissection diagnosed by TTE, 8 males and 5 females were taken from 789,114 TTE studies performed between 1985 and 2014. All underwent cardiac surgery during which their diagnosis was confirmed. The etiology, location, 2-dimensional morphology, and color Doppler findings of IVS dissection were noted.The right sinus of Valsalva (SOV) was involved in 11 of the 13 patients. In 5 patients, a single aneurysm of the right SOV was seen dissecting into the IVS. One patient with a combination of a bicuspid aortic valve and a right SOV aneurysm dissected into the IVS. In 4 patients, aortic valve infective endocarditis resulted in IVS dissection. In 1 patient, mechanical aortic valve prosthetic replacement was complicated by annular detachment and a severe paravalvular leak causing IVS dissection. In all 11 patients, TTE showed a dissecting cystic-like mass in the IVS from the base to the mid-septum or confined to the septal base. The path of the dissection in these 11 patients was traced to the right SOV and communications between the IVS dissection and the aortic root were identified. In the remaining 2 patients, IVS dissection followed septal rupture due to a myocardial infarction, and communication was seen between the IVS dissection and the right ventricle.The study showed that most of the dissections of the IVS commence in the right SOV, due to either congenital anomalies or infective endocarditis, or following aortic valve replacement or myocardial infarction. The TTE characteristic of IVS dissection is a cystic-like mass seen in the IVS.

Figure 1

(Patient #2) Transthoracic echocardiogram (parasternal long axis view) showed the right sinus of Valsalva aneurysm and the entry site of rupture (arrow) into the dissecting cystic-like cavity in the interventricular septum. AO = aorta, LA = left atrium, LV = left ventricle.

Figure 2

(Patient #2) Transthoracic echocardiogram (parasternal long axis view with color) showing the communication between the right sinus of Valsalva aneurysm and the dissection in the interventricular septum.

Figure 3

(Patient #7) Transthoracic echocardiogram (parasternal long axis view) showing thickened aortic valve leaflets with vegetations and the entry site of rupture (arrow) from the right sinus of Valsalva into the dissecting cystic-like false cavity in the interventricular septum (see also video 1). AO = aorta, FC = false cavity, LA = left atrium, LV = left ventricle.

Figure 4

(Patient #7) Transthoracic echocardiogram (parasternal long axis view with color) showing both the communication between the right sinus of Valsalva aneurysm and the dissecting cavity in the interventricular septum and the communication between the dissecting cavity in the interventricular septum and the left ventricle (see also video 2).

Figure 5

(Patient #11) Transthoracic echocardiogram (parasternal long axis view) showing a mechanical aortic valve in situ with annular detachment and the entry site of rupture (arrow on right) from the right sinus of Valsalva aneurysm into the dissecting false interventricular septal cavity, and the entry site of rupture (arrow on left) from the false interventricular septal dissecting cavity into the left ventricular cavity. (See also video 3). FC = false cavity, LA = left atrium, LV = left ventricle.

Figure 6

(Patient #11) Transthoracic echocardiogram (parasternal long axis view with color) showing the communication (arrow) from the right sinus of Valsalva aneurysm into the interventricular septal cavity, and the entry site of rupture from the false interventricular septal dissecting cavity into the left ventricular cavity. LA = left atrium, LV = left ventricle.

Figure 7

(Patient #11) Transthoracic echocardiogram (apical 5 chamber view with color) showing 2 flow jet communications from interventricular septal dissecting cavity to the left ventricular cavity. FC = false cavity, LA = left atrium, LV = left ventricle.

Figure 8

(Patient #11) Transthoracic echocardiogram (parasternal long axis view) showing a Dacron patch used to repair the rupture of right sinus of Valsalva (arrow) and to repair the annular detachment of the mechanical valve. AO = aorta, LA = left atrium, LV = left ventricle.

Figure 9

(Patient #12) Transthoracic echocardiogram (apical 4 chamber views) showing interventricular septal dissection following an anterior septal myocardial infarction. (A) The short arrows indicate the rupture of the interventricular septum both in left ventricle and right ventricle side. (B) Color flow (long arrow) shows the dissecting cavity of interventricular septum. LA = left atrium, LV = left ventricle, RA = right atrium, RV = right ventricle.