Background
L-arginine, the precursor of nitric oxide, may restore nitric oxide levels and bioavailability and influence symptom severity, quality of life (QoL), physical performance, and left ventricular (LV) diastolic abnormalities in patients with chronic systolic heart failure (HF). The aim was to evaluate the effects of orally administered L-arginine in chronic HF patients.
Material and Method
A parallel double-blind multicenter randomized study was performed in 68 patients (mean age: 64+/-11 years) with mild-to-moderate systolic HF (NYHA class II-III) and LV ejection fraction (EF) Results
The mean difference in MLWHFQ score from baseline was -9.7 in the L-arginine (95%CI: -14.6, -4.7) and -4.2 in the placebo group (95%CI: -8.9, +0.55). The difference between groups was not statistically significant. Among the patients with advanced LV diastolic dysfunction, 7 of 9 in the L-arginine and 3 of 6 in the placebo group showed reversible restrictive mitral flow after therapy.
Conclusions
Although no significant difference in QoL score was found between L-arginine and placebo, the results showed that L-arginine significantly improved QoL from baseline, in contrast to placebo, in chronic HF patients.

Keywords: Stroke Volume - drug effects, Questionnaires, Quality of Life, Nitric Oxide - physiology, Heart Failure, Systolic - physiopathology, Exercise Test, Echocardiography, Double-Blind Method, Arginine - therapeutic use, Administration, Oral, Vasodilation - drug effects, Ventricular Dysfunction, Left - physiopathology