One hundred and one representative post-myocardial infarction (MI) patients were investigated with radionuclide angiocardiography (RNA) and exercise test within 1 month of the MI and after 6 and 12 months. From the RNA were calculated the left ventricular ejection fraction (LVEF) and a quantified phase image, the phase standard deviation (phase-SD), representing the timing of the left ventricular contraction. The mean phase-SD was significantly higher among these patients (18 degrees, 19 degrees and 18 degrees, respectively, at the three investigations) compared to phase-SD in normals (6 degrees), indicating an impaired timing of the left ventricular (LV) contraction. At all three investigations a significant correlation was found between the phase-SD and the LVEF (r = -0.58, r = -0.74 and r = -0.75, respectively) and the corrected QT interval (r = 0.27, r = 0.44 and r = 0.39, respectively). Maximal serum ASAT in patients with their first MI correlated significantly to phase-SD. Low exercise capacity or unfavourable NYHA classification was associated with high phase-SD. Phase-SD higher than mean was also associated with significantly increased mortality during the follow-up year (p = 0.0057). In conclusion, phase-SD, reflecting the timing of the LV contraction wave, is easily accessible and clinically relevant. It merits further investigation as a prognostic factor after an MI.