Effects of long-term coenzyme Q10 and captopril treatment on survival and functional capacity in rats with experimentally induced heart infarction. The effects of coenzyme Q10 (CoQ) and captopril on functional capacity, hemodynamics and survival were studied in 154 rats that recovered after experimental myocardial infarction. Rats were randomized into four groups receiving either CoQ, captopril, a combination of the two drugs or 1 ml of tap water once daily for 12 weeks from the day of coronary artery ligation. CoQ as well as captopril and the combined treatment significantly improved exercise capacity as evaluated by lactate production during a standardized treadmill exercise test. No significant changes in heart rate or mean blood pressure were observed during the study in the captopril-treated group. CoQ treatment increased the maximum heart rate significantly, whereas no effect on mean blood pressure was observed. Both captopril and CoQ decreased pulmonary congestion. Furthermore, the data may suggest that captopril prevents right ventricular hypertrophy seen in placebo-treated rats with large infarcts. This was not observed after CoQ treatment. Captopril treatment improved 3-month probability of survival (93%) as compared with placebo (74%) (P less than .05). CoQ and the combined treatment tended to improve survival, but this was, however, not statistically significant. 