Abstract
To assess the clinical efficacy of L-camititine in chronic heart failure, we measured echocardiographic left ventricular dimensions, peak oxygen consumption (peak Vo2), and anaerobic threshold (AT) before and after a long-term administration of L-carnitine (1, 800 mg/day, 12 weeks) in 18 patients with left ventricular dysfunction (I to III in New York Heart Association fuhctional classification). Peak Vo2 and AT were determined by the continuous respiratory gas analysis during a symptom-limited maximal bicycle exercise test. The patiehts were divided into 2 groups according to the presence of exercise-induced ST depression (>0.1 mV) in the control exercise test: 9 patients with ST depression (Group I) and 9 patients without ST depression (Group II). In Group I, exercise-induced ST depression was significantly improved by the chrohic admihistratioh of L-carnitine (0.17±0.03 mV to 0.12±0.03 mV, mean±SE, P<0.05). Coincidentally both peak Vo2 and AT significantly increased after L-carnitine administration when compared to those before administration in Group I (21.3±2.5, 17.2±27 to 24.3±2.3, 20.2±2.3 ml/min·kg, re spectively, mean±SE, P<0.05). In Group II there was no sighificant change in electro cardiographic findings, peak Vo2, or AT by the drug administration. The intemal dimensions and the fractional shortening of the left ventricle were not altered by the L-carnitineadministration in both grotips. Thus, we conclude that L-carhitine can increase exercise capacity in patients with chronic heart failure when they are attended with exercise-induced ST depression, possibly by improving abnormalities in the myocardial fatty acidenergy metabolism during exercise.
