Abstract

In acute myocardial infarction the overall left ventricular pump function and the regional performance of the infarcted and non-infarcted myocardial segments were studied serially by echocardiographic techniques in 24 patients during the first week of their illness. Left ventricular cavity sizes were acutely increased in 62 per cent of the patients (P less than 0-005). The end-systolic diameter in anterior infarcts increased to the greatest extent, +44 per cent, the end-diastolic diameter by +27 per cent, giving a volume of 246+/-25 ml. In the anterior myocardial infarcts all the function parameters deteriorated more than in the posteroinferior ones. Ejection fraction was subnormal (P less than 0-005) in every patient, and mean circumferential fibre shortening (Vcf) was slowed by about 30 per cent (P less than 0-005). Regionally, contraction of the infarcted area of the ventricle was asynergic in every instance, and its function was almost totally lost (P less than 0-001). Systolic paradoxical motion was a constant and stable finding in the anterior infarctions but not so in the posterior ones. While this asynergic systolic contraction may distort echocardiographic measurement of the end-systolic left vlic phase. The serial deviations from normal in the amplitude or velocity of the uninvolved segments were small, but in the case of clearly enlarged end-diastolic volumes these figures in fact indicate supernormal, compensating function. Both overall and regional performance were worst within the first 3 days of infarction, improving thereafter. The patient with a fatal course showed, instead, progressive deterioration. This noninvasive left ventriculogram by ultrasound gives valuable insight into overall pump function and ventricular volumes, little studied so far in acute infarction, and it may serially quantify the segmental function of both the infarcted and uninvolved regions.