T Wave Changes after Acute Myocardial Infarction Predicting Reinfarction

Abstract

Of 420 consecutive patients with acute myocardial infarction who survived the coronary care unit period, 57 developed 63 reinfarctions with 16 deaths within 3 mo. (reinfarction group). Of the remaining 363 patients, 28 died without evidence of reinfarction during the same observation period and 335 survived. The last ECG before discharge, or prior to a reinfarction in hospital, of the reinfarction patients were studied and compared with time-matched ECG from the 335 survivors without reinfarction. In ECG without interfering patterns, the slope of the ascending limb of a negative T wave was measured as the angle to the vertical plane (interobserver variation .ltoreq. 5.degree. in 95%). Of the 63 reinfarctions, 40% had a steeply ascending limb of a negative T wave (T wave angle .ltoreq. 55.degree. in lead II, .ltoreq. 35.degree. in CR4 and/or .ltoreq. 40.degree. in CR7) and a QRS complex without signs of infarction in the same lead (abnormal Q waves or abnormal R wave progression). The same criteria were fulfilled by 6% of 335 survivors without reinfarction (P < 0.001) and by 1 of the 28 patients who died without reinfarction. A steeply ascending limb of a negative T wave in the acute phase of a myocardial infarction heralds a reinfarction if the QRS complex of the same lead does not show signs of infarction (3-mo. sensitivity 40% and predictive value 53%). A T wave angle .ltoreq. 35.degree. in CR 4 corresponds to .ltoreq. 40.degree. in V4. CR7 is not transferable to V, but was the least predictive lead.