The relationship between the time course of inverted T-waves during the acute phase and infarct size and left ventricular (LV) function was studied in 46 patients (mean age: 57.3 +/- 9.7 years) with reperfused first anterior wall acute myocardial infarction (MI). All patients had coronary reflow within 6 hrs after the onset of MI and were without subsequent reocclusion for at least 14 days. The T-wave inverted progressively and rapidly with maximum depth between 26 and 60 hrs (mean time: 37.1 +/- 12.4 hrs). A significant correlation was found between the maximum T-wave depth (T-peak) in all patients and peak CPK, left ventricular ejection fraction (LVEF), regional wall motion, % abnormally contracting segment (%ACS), end-diastolic and end-systolic volume indices (EDVI,ESVI) at day 14 after the onset of MI (p < 0.05). T-wave inversion within 24 hrs after onset of MI was observed in 43 patients (93%). There were significant correlations between the depth of T-wave inversion occurring in patients 24 hrs after onset of MI (T24) and peak CPK, LVEF, regional wall motion, % ACS, EDVI, and ESVI at day 14 (p < 0.05). The sensitivity and specificity for patients with EDVI > 87.0 ml/m2 at day 14 increased by more than 20% over normal values, predicted by a T24 of 3.0 mm or less, were 94% and 93%, respectively. The sensitivity and specificity for patients with EF < 40% at day 14 predicted by a T24 of 3.0 mm or less, were 90% and 75%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)