Effects of L-Carnitine on Exercise Tolerance in Patients with Stable Angina Pectoris

The effects of L-carnitine (900mg, p.o. daily) on exercise performance were studied in 12 patients with stable effort angina using a multistage treadmill exercise test. Exercise tests were performed at the end of the placebo period and after 4 and 12 weeks of carnitine therapy. While 12 patients experienced angina during treadmill tests in the placebo period, 2 patients were free of angina after treatment with carnitine. The mean exercise time was 11.4±0.7min (mean±SE) in the placebo period. This increased significantly to 12.2±0.5min (p<0.05) after 4 weeks and 12.8±0.5min (p<0.01) after 12 weeks of treatment with carnitine. The time required for 1mm ST depression to occur was 6.4±0.9min in the placebo period. This increased significantly to 7.6±0.9min (p<0.01) after 4 weeks and 8.8±1.0min after 12 weeks of treatment with carnitine. There was significantly less ST segment depression during the same exercise load after 12 weeks of treatment as compared with that in the placebo period (p<0.05). The heart rate and the pressure rate product at the same work load showed no significant difference among the 3 testing periods.The results of this study suggest that L-carnitine may improve exercise tolerance in patients with effort angina.