Abstract
Echocardiography and cross-sectional echocardiography have proved to be valuable in the study of the left ventricular wall motion and the assessment of left ventricular function. Recently, echocardiography has revealed a characteristic ventricular septal motion in patients with left bundle branch block. It has been postulated that abnormal septal motion is related to altered sequence of activation and contraction. The purpose of this study was (1) to analyze motions of interventricular septum and the left ventricular posterior wall in patients with complete left bundle branch block by echocardiography and cross sectional echocardiography; (2) to relate septal motion during the right ventricular endocardial pacing to that in LBBB; (3) to compare septal motion in LBBB with that in septal infarction. Materials and Methods: Echocardiogram and cross-sectional echocardiogram of thirty patients with complete left bundle branch block (LBBB) were compared with those of five patients with complete A-V block during right ventricular endocardial pacing, twenty patient with anteroseptal infarction, and twenty normal subjects. Echocardiogram and cross-sectional echocardiogram were recorded simultaneously with electrocardiogram (ECG) and phonocardiogram (PCG), using an ALOKA SSD-33 instrument utilizing a 2.25 MHZ unfocused transducer of 10mm diameter with a repetition rate of 1000 inpulses per second. Ultrasonic cross-section (stop-action B-scan) were made along the long axis of the left ventricle, with the transducer tilting in an arc setor from the base of the heart to the apex, at end-diastole (the peak of R-wave in ECG), early systole (pre-ejection period) and end-systole (aortic component of the second heart sound in PCG), respectively.
