OBJECTIVES: The aim of this study was to analyze whether L-arginine (L-arg) has comparable or additive effects to physical exercise regarding endothelium-dependent vasodilation in patients with chronic heart failure (CHF). BACKGROUND: Endothelial dysfunction in patients with CHF can be corrected by both dietary supplementation with L-arg. and regular physical exercise. METHODS: Forty patients with severe CHF (left ventricular ejection fraction 19 +/- 9%) were randomized to an L-arg group (8 g/day), a training group (T) with daily handgrip training, L-arg and T (L-arg+T) or an inactive control group (C). The mean internal radial artery diameter was determined at the beginning and after four weeks in response to brachial arterial administration of acetylcholine (ACh; 7.5, 15, 30 microg/min) and nitroglycerin (0.2 mg/min) with a transcutaneous high-resolution 10 MHz A-mode echo tracking system coupled with a Doppler device. The power of the study to detect clinically significant differences in endothelium-dependent vasodilation was 96.6%. RESULTS: At the beginning, the mean endothelium-dependent vasodilation in response to ACh, 30 microg/min was 2.54 +/- 0.09% (p = NS between groups). After four weeks, internal radial artery diameter increased by 8.8 +/- 0.9% after ACh 30 microg/min in L-arg. (p < 0.001 versus C), by 8.6 +/- 0.9% in T (p < 0.001 versus C) and by 12.0 +/- 0.3% in L-arg +/- T (p < 0.005 versus C, L-arg and T). Endothelium-independent vasodilation as assessed by infusion of nitroglycerin was similar in all groups at the beginning and at the end of the study. CONCLUSIONS: Dietary supplementation of L-arg as well as regular physical exercise improved agonist-mediated, endothelium-dependent vasodilation to a similar extent. Both interventions together seem to produce additive effects with respect to endothelium-dependent vasodilation.
With permission from Excerpta Medica Inc.

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