Left ventricular performance was evaluated noninvasively in 111 patients participating at one study center in the Norwegian Multicenter Study on Timolol After Myocardial Infarction. Systolic time intervals were measured in 55 patients treated with timolol and in 56 patients receiving placebo. Measurements were made before randomization, and after 1, 3 and 12 months of treatment. During the treatment period, the pre-ejection period/left ventricular ejection time ratio was significantly lower in the timolol-treated group, indicating better left ventricular function than in the placebo-treated patients. In the 27 patients who died during the follow-up period of 50 to 72 months, there was a significant increase in the pre-ejection period/left ventricular ejection time ratio from baseline to the last performed recording, indicating a deterioration in left ventricular performance in these patients. No such change occurred in the group that survived the entire follow-up period. Deterioration of left ventricular function is related to a high long-term mortality rate after myocardial infarction, and left ventricular function is better preserved in patients treated with timolol than in patients receiving placebo.