Postmyocardial infarction pain and infarct extension in the coronary care unit: role of two-dimensional echocardiography

Department of Medicine (Cardiology), Veterans Administration Medical Center, Brockton-West Roxbury, Massachusetts 02132.

Recent data suggest that patients who manifest extension of their acute myocardial infarct have a worse prognosis than to those who do not have this complication and, if identified early, may be candidates for more aggressive intervention. Serial two-dimensional echocardiography was used to diagnose myocardial infarct extension in 33 consecutive patients and its sensitivity was compared with that of electrocardiography (ECG) and serum creatine kinase determination. Infarct extension was diagnosed clinically using ECG and enzymatic criteria. The echocardiograms were scored using a weighted regional scoring system, with each segment of the left ventricle ascribed a percent of the total left ventricular mass. Abnormal regions were summed to yield a percent asynergy. In the postinfarction period, 19 episodes of acute ischemia occurred; in 9 of these episodes clinical extension was confirmed, and in 7 of the 9 episodes echocardiographic extension was detected. In the patients in whom infarct extension was documented clinically, the mean asynergy score increased from a mean of 19.2 +/- 11.3% to 36.1 +/- 18.2% (p less than 0.01). Where no extension was detected, the asynergy score improved from the initial 31.5 +/- 24.1% to 28.3 +/- 21.9% (p less than 0.05). The extent of the change in echocardiographic wall motion abnormality was not predicted by the amount of creatine kinase reelevation. Electrocardiography alone failed to distinguish which episodes of ischemia represented infarct extension and which did not. Greater degrees of asynergy were associated with worse in-hospital mortality. Two-dimensional echocardiography is a useful method for detecting myocardial infarct extension providing a means of assessing functional impact and prognosis.