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[Role of M-mode and 2-dimensional (sector-scan) echocardiography in studying postinfarct ventricular kinetic changes]
Abstract:
20 patients with previous myocardial infarction clinically suspected to have large impairment of ventricular wall kinesis were studied to evaluate the contribution of M-mode and two-dimensional echocardiography compared with the cineangiographic study in detecting left ventricular asynergy. Two-dimensional cross-sectional echocardiography yielded a satisfactory overlapping of results with ventriculography as far as left ventricular internal dimension and apical and posterior wall kinesis were concerned. The two-dimensional study proved to be an useful technique to observe the interventricular septum, in all its extension and the lateral wall as well. The M-mode technique, on the other hand, provided a reliable method, by means of the mitral valve echo, to determine the presence of elevated left-ventricular end-diastolic pressure; this was indicated by the occurrence of a B point, on the AC slope. A late opening of the mitral valve compared with the onset of left ventricular posterior wall relaxation phase, and other anomalies observed on the CD slope (SAM or pseudo-SAM), indicated pathological left ventricular kinesis. The failure of the left ventricular posterior wall to reach the septum moving the transducer from the aorta to the cardiac apex was considered indicative of apical dilatation, even if limited by a great number of false negatives. M-mode echocardiography provided also a quantitative evaluation of septal and postero-basal wall movement (particularly important from a prognostic point of view) and left ventricular end-diastolic dimension which, if corrected by body surface, resulted similar to those obtained by the two-dimensional technique. M-mode and Two-dimensional cross sectional echocardiography appeared to be complementary techniques which allow an adequate evaluation and diagnosis of left ventricular asynergy. They seem to be particularly useful to follow prospectively patients affected by myocardial infarction.