THE EFFECT OF DIETARY CREATINE SUPPLEMENTATION ON SKELETAL-MUSCLE METABOLISM IN CONGESTIVE-HEART-FAILURE

Aims To assess the effects of dietary creatine supplementation on skel etal muscle metabolism and endurance in patients with chronic heart fa ilure. Methods A forearm model of muscle metabolism was used, with a c annula inserted retrogradely into an antecubital vein of the dominant forearm. Maximum voluntary contraction was measured using handgrip dyn anometry. Subjects performed handgrip exercise, 5 s contraction follow ed by 5 s rest for 5 min at 25%, 50%, and 75% of maximum voluntary con traction or until exhaustion. Blood was taken at rest and 0 and 2 min after exercise for measurement of lactate and ammonia. After 30 min th e procedure was repeated with fixed workloads of 7 kg, 14 kg and 21 kg . Patients were assigned to creatine 20 g daily or matching placebo fo r 5 days and returned after 6 days for repeat study. Results Contracti ons (median (25th, 75th interquartiles)) until exhaustion at 75% of ma ximum voluntary contraction increased after creatine treatment (8 (6, 14) vs 14 (8, 17), P=0.025) with no significant placebo effect. Ammoni a per contraction at 75% maximum voluntary contraction (11.6 mu mol/l/ contraction (8.3, 15.7) vs 8.9 mu mol/l/contraction (5.9, 10.8), P=0.0 37) and lactate per contraction at 75% maximum voluntary contraction ( 0.32 mmol/l/contraction (0.28, 0.61) vs 0.27 mmol/l/contraction (0.19, 0.49), P=0.07) fell after creatine but not after placebo. Conclusions Creatine supplementation in chronic heart failure augments skeletal m uscle endurance and attenuates the abnormal skeletal muscle metabolic response to exercise.