The purpose of this was to investigate the effect of coenzyme Q10 (CoQ10) in patients with congestive heart failure (CHF) by measuring the possible improvement of certain relevant hemodynamic heart parameters. A statistic aggregation method know as a meta-analysis was used to measure the changes in the cardiac parameters. To begin with we collected the total number of randomized controlled trials and from a total of 14 studies published in the period of 1984-1994, eight studies met our inclusion criteria. The rest were excluded because of a lack of data which made a meta-analysis impossible. The relevant effect parameters investigated were stroke volume (SV), cardiac output (CO), ejection fraction (EF), cardiac index (CI), end diastolic volume index (EDVI), systolic time intervals (PEP/LVET) and total work capacity (Wmax). Seven meta-analyses were performed, one for each of the parameters, and the calculated effect sizes were all positive. Statistical significance could be demonstrated for all of the parameters except the PEP/LVET and Wmax thereby indicating an improvement of greater or lesser magnitude in the CoQ10 group as opposed to the placebo group. Accordingly, the average patient in the CoQ10 group had a better score with regard to SV and CO than 76 and 73% respectively of the patients in the placebo group. In conclusion, supplemental treatment of CHF with CoQ10 is consistent with an improvement of SV, EF, CO, CI and EDVI. Homogeneity could be established for SV and CO. Additional clinical trials of the effect of CoQ10 on CHF are necessary, but, on the basis of the evidence currently available, the possibility remains that CoQ10 will receive a well-documented role as an adjunctive treatment of CHF.