Interventricular septal dissection secondary to acute inferior myocardial infarction: case series and literature review

Abstract

Background: Interventricular septal dissection is a critical disease characterized by the separation of the intraventricular septum into two layers, forming an intermediate layer with a cystic cavity that communicates with the root of the aorta or ventricle. It has low morbidity and high mortality rates.

Case presentation: Case 1: A 58-year-old male with a history of hypertension and smoking presented to a local hospital due to chest tightness and pain for 4 days. Coronary angiography revealed diffuse lesions from the proximal to the middle segment of the left circumflex branch, with 80% stenosis at its most severe point, and complete occlusion of the proximal segment of the right coronary artery. A stent was implanted in the middle of the right coronary artery. Three months later, the patient was misdiagnosed with an aneurysm of the membranous ventricular septum with defect via echocardiography at the local hospital. After the implantation of a stent in the left circumflex branch, the patient came to our hospital for further diagnosis and treatment. The first ultrasound of our hospital misdiagnosed it as ventricular septal rupture, and a senior ultrasound doctor diagnosed the patient with interventricular septal dissection secondary to myocardial infarction. The patient underwent follow-up echocardiography every 1-2 months for 6 months. The patient remains asymptomatic with stable hemodynamics. The original treatment regimen and follow-up continues. Case 2: A 70-year-old male was admitted to a local hospital due to repeated chest distress for more than 20 years that worsened over several hours. Coronary angiography revealed complete occlusion of the right coronary artery. Cardiogenic shock occurred after percutaneous coronary intervention. The initial several echocardiography of the local hospital and our hospital misdiagnosed it as interventricular septal rupture secondary to myocardial infarction. The later echocardiography diagnosed it as interventricular septal dissection with rupture secondary to myocardial infarction. The patient underwent interventricular septal repair and mitral valvuloplasty after 25 days of medical treatment and died of multiple organ failure on the fourth day after the operation.

Conclusions: These two cases illustrate a complication of acute myocardial infarction and highlight the importance of echocardiography in its diagnosis. By exploring the etiology, pathogenesis, and key diagnostic points of IVSD, this study aims to provide valuable insights for clinical practice.

Keywords: Echocardiography; Interventricular septal dissection; Interventricular septal rupture; Myocardial infarction.

Fig. 1

First ECG performed upon admission to the local hospital showing ST elevation in leads II, III, and aVF

Fig. 2

TTE of the parasternal short-axis view for a patient in our hospital. a 2D revealed an 6 mm-laceration in the endocardium on the left ventricular side of the interventricular septum. b CDFI revealed bidirectional shunting between the left ventricle and the false lumen through the laceration. c PW revealed that the peak systolic flow velocity at the endocardial defect of the basal segment of the posterior septum was 257 cm/s from the left ventricle to the false lumen during systole, and 163 cm/s from the false lumen to the left ventricle during diastole

Fig. 3

TTE of the parasternal short-axis view on the 22nd day after AMI. a 2D image revealed IVSD with multiple lacerations on both the left and right ventricular sides. b PW revealed the peak systolic flow velocity at one of the lacerations of the right ventricular side of the IVSD was 258 cm/s

Fig. 4

TEE of the parasternal short-axis view on the 25th day after AMI. a 2D image revealed a false lumen with multiple lacerations on both the left and right ventricular sides. b CDFI revealed the left-to-right shunting through multiple lacerations on both the left and right ventricular side of the false lumen. c 2D image revealed hyperechogenicity in the interventricular septum