In the Program of Surgical Control of Hyperlipidemia, the relation of the Minnesota Q-QS codes for rest electrocardiograms to left ventricular (LV) function was studied in patients with healed myocardial infarction (MI). Of 838 subjects enrolled in the study, 477 (57%) had codable Q-QS patterns at the time of randomization. There was an extremely high correlation between the level of the Minnesota code and concurrent LV function, the latter being determined on left ventriculography by both ejection fraction and the number of segmental wall motion abnormalities. Subjects without a Q-QS code had less myocardial damage than did those with a code present in a single cardiac area. Extent of LV damage correlated with the level of significance of the Q-QS code, and when the code was present in only 1 cardiac location damage was greatest if the anteroseptal area was involved. Q-QS codes present in 2 rather than 1 cardiac area were associated with an even greater degree of LV damage. A previous study has shown a strong correlation between LV function and the Minnesota codes when the latter were recorded 0.5 to 5 years (mean 2.2) earlier at the time of the acute MI. The present data show that the relation between LV function and the Minnesota codes after an acute MI persists over time and is even stronger when both are determined in the healed state at a time remote from the acute event.