Detection of left ventricular asynergy in myocardial infarction by means of ultrasono-cardiotomography and M-mode echocardiography.

The movements of the left ventricular wall in cases of myocardial infarction were studied by ultrasono-cardiotomography and M-mode echo-cardiography. Ultrasono-cardiotomographic and echocardiographic data were collected from 15 consecutive patients with transmural myocardial infarction ranging in age from 28 to 60 years (4 with antero-septal infarction, 5 with postero-inferior infarction, and 6 with infarction of other areas) and also from healthy control subjects. In myocardial infarction, a delay in timing and a decrement in amplitude of the excursion of the infarcted area were observed. As the result, compensatory movement occurred in the non-infarcted area. This compensatory movement was a major contributing factor for the maintenance of the function of the left ventricle. In antero-septal infarction, the pump function was compensated for by the movement of the left ventricular posterior wall (LVPW) and by that of the non-infarcted area of the interventricular septum (IVS). On the other hand, in postero-inferior infarction, the pump function was mainly compensated for by an increment in movement of IVS. This compensatory movement, which was very strong in the acute stage of myocardial infarction, decreased with time after infarction. On the other hand, in the hypokinetic infarcted area, there was a gradual increment of the amplitude of excursion with time after infarction. These findings reflected the degree of the development of collateral circulation. It was found that the degree of asynergy could be determined by the evaluation of the delay in timing and amplitude of the excursion, and of mVCF at basal, middle, and apical portions of the left ventricle.