Coronary artery ectasia (CAE) is a rare form of coronary artery disease. It has previously been shown that nitrate derivatives induce exertional angina in patients with CAE. Furthermore, there is limited data about the effects of other anti-ischemic agents in CAE. The aim of this study was to investigate the effect of trimetazidine on exercise performance in patients with CAE. The study population consisted of 56 patients with isolated CAE (32 males, mean age: 58 9 years). The presence of myocardial ischemia was evaluated by treadmill exercise test. The exercise test was positive in 49 patients at baseline and in 27 patients during trimetazidine therapy (P < 0.01). The exercise test induced angina in all of the patients who have had a positive test result. Significant ST depressions were observed in 42 and 23 patients before and after the treatment, respectively (P < 0.01). The extent of ST depression at peak exercise was significantly lower on trimetazidine (0.9 +/- 0.5 vs 1.5 +/- 0.6 mm, P < 0.01). With trimetazidine, the exercise duration increased from 7.8 +/- 2.1 to 8.7 +/- 2.4 min (P = 0.04) and cardiac work-load also increased from 8.9 +/- 2.3 to 10.4 +/- 2.1 mets (P < 0.01). The results suggest that trimetazidine can relieve exercise-induced angina and improve exercise performance in patients with CAE.