A meta-analysis by Soja and Mortensen reported a significant improvement in stroke volume, ejection fraction, cardiac output, cardiac index, and end-diastolic volume index, as a result of coenzyme Q10 supplementation. (18)
Sander et al authored a meta-analysis of 11 studies with CoQ10 doses ranging from 60 to 200 mg/day and treatment periods ranging from 1 to 6 months and reported a 3.7% net improvement in the ejection fraction and an average increase in cardiac output of 0.28 L/min (19).
Creatine supplementation and congestive heart failure (CHF):
Muscle endurance improved in a double-blind, placebo-controlled crossover study of patients with chronic heart failure. Treatment with 20 g of creatine for 5 days increased the amount of exercise they could complete before they reached exhaustion. No effect was reported in the placebo group. Chemicals produced during exhaustive exercise (ammonia and lactate) were reduced (-2.7 and -0.05 mumol/l/contraction, respectively) with use of creatine but not placebo. (11)