2-D echocardiographic analysis of interventricular septal motion: concept of an anterior and posterior part to the septum.

2-D echocardiography was performed in 50 patients with transmural anteroseptal (group 1) or inferior myocardial infarction (group 2). Twenty-four patients with myocardial infarction had diagnostic coronary arteriography. Twenty-five normal subjects served as controls. The interventricular septum was subdivided into proximal and distal halves. In the parasternal long axis view (PSLAX), interventricular septum asynergy was seen in 96% of patients of group 1 and none in group 2. In the apical four chamber view (A4C), the proximal interventricular septum was abnormal in 48% of group 2 patients, but only one patient in group 1. The distal half of the interventricular septum in the A4C was abnormal in 48% of patients in group 1 and 12% in group 2. Complete asynergy of the interventricular septum in the PSLAX view was seen in 80% of patients with proximal stenosis in the left anterior descending artery (LAD) in association with anteroseptal myocardial infarction. Distal asynergy in this view was noted in all patients with a stenosis distal to the first septal perforator. In conclusion, the PSLAX visualizes the anterior interventricular septum and demonstrates wall motion abnormalities associated with anteroseptal infarction; complete asynergy of the interventricular septum in the PSLAX view suggests an anteroseptal infarction with proximal LAD stenosis; the A4C visualizes the posterior interventricular septum and proximal wall motion abnormalities are seen in inferior infarction while distal septal wall motion abnormalities occur in anteroseptal or inferior infarction.