The usefulness of percutaneous transluminal coronary angioplasty (PTCA) in patients with evolving myocardial infarction remains controversial. We retrospectively assessed the efficacy of PTCA on myocardial salvage in acute myocardial infarction in comparison with the efficacy of intracoronary thrombolysis (ICT). Sixty-two patients with initial anteroseptal myocardial infarction who had been treated within 6 hrs after the onset of chest pain were categorized into 4 groups: 1) spontaneous recanalization: n = 14, 2) successful PTCA: n = 25 (this group was further subdivided into 2 groups: direct PTCA group, primary PTCA without prior ICT: n = 19; and rescue PTCA group, PTCA after unsuccessful ICT: n = 6), 3) successful ICT group (n = 12), and 4) unsuccessful recanalization group (n = 11). Left ventricular function in the chronic phase was assessed by contrast ventriculography using the global ejection fraction (EF) and regional wall motion (RWM) was assessed by the centerline method. Patients with recanalization had a significantly higher EF than did those without (62 +/- 12 vs 50 +/- 13%, p < 0.01). The mean EFs for groups with successful reperfusion were as follows: 65 +/- 8% for the spontaneous recanalization group, 61 +/- 14% for PTCA group (64 +/- 13% for direct PTCA group, 51 +/- 13% for rescue PTCA group) and 60 +/- 12% for the ICT group. The EFs for the spontaneous recanalization group and the direct PTCA group were significantly greater than that for the rescue PTCA group. The time to reperfusion and the thrombolysis in myocardial infarction (TIMI) flow grade before reperfusion did not affect the preservation of global left ventricular function. RWM of the infarcted area in patients with recanalization were less hypokinetic than that in patients without (p < 0.01). The mean RWM (SD/chord) in the successfully reperfused groups were -2.3 +/- 1.2 for the spontaneous recanalization group, -2.6 +/- 1.2 for the PTCA group (-2.3 +/- 1.1 for the direct PTCA group, -3.3 +/- 1.0 for rescue PTCA group) and -3.0 +/- 0.5 for the ICT group. Hypokinesis of the infarcted area was more severe in the rescue PTCA group than in the spontaneous recanalization group and the direct PTCA group (multiple comparison test p < 0.01, respectively), and hypokinesis was more severe in the ICT group than in the direct PTCA group (Student's t-test, p < 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)