The impact of coenzyme Q10 on systolic function in patients with chronic heart failure.

BACKGROUND Coenzyme Q10 (CoQ10) is an endogenous cofactor in the mitochondrial energy production. CoQ10 has been touted to improve heart failure, but its effect on systolic function is controversial. Several small, randomized controlled trials evaluating CoQ10 showed variable results and were largely underpowered. We conducted a meta-analysis of these trials to evaluate the impact of CoQ10 therapy on ejection fraction and cardiac output. METHODS AND RESULTS A systematic literature search was conducted to identify randomized, controlled trials of CoQ10 in heart failure between 1966 and June 2005. Subgroup analysis was conducted to assess clinical heterogeneity between trials. Of the 11 trials identified, 10 evaluated ejection fraction (n = 277) and 2 evaluated cardiac output (n = 42). Doses ranged from 60 to 200 mg/day with treatment periods ranging from 1 to 6 months. There was a 3.7% net improvement in ejection fraction (95% CI 1.59-5.77; P < .00001 for statistical heterogeneity). A more profound effect among patients not receiving angiotensin-converting enzyme inhibitors was observed (6.74% [95% CI 2.63-10.86]). Cardiac output increased an average of 0.28 L/minute (95% CI 0.03-0.53; P = .96 for statistical heterogeneity). CONCLUSION CoQ10 enhances systolic function in chronic heart failure, but its effectiveness may be reduced with concomitant use of current standard therapies.