A literature review published in Open Heart (2015 Oct 19;2(1):e000326. doi: 10.1136/openhrt-2015-000326. eCollection 2015) looked at the value of CoQ10 supplementation for patients with heart failure. CoQ10 is involved with electron transport in the mitochondria; in other words, it is important for the production of cellular energy. It is produced by every cell and acts to protect the cell membrane as an antioxidant. Patients with congestive heart failure tend to have low levels of CoQ10, with levels decreasing as the disease gets worse.

There have been a number of studies that have shown that supplementation with CoQ10 improves cardiac function. The multicentre randomized placebo-controlled Q-SYMBIO trial has assessed the impact of supplemental CoQ10  on patients with heart failure. It is the largest study on CoQ10 and heart failure in the world. Begun in 2003, study showed that patients supplemented with CoQ10  had a 43% decrease in cardiovascular death compared to the placebo group. Only 15% of the patients in the CoQ10 group experienced serious heart events, called MACE events, compared with 26% of the patients who received the placebo, corresponding to a 43% relative reduction, which was a statistically significant result.

Supplementation with CoQ10 also significantly reduced the risk of death from all causes by 42% compared to the placebo group. The number of unplanned hospitalizations was lower in the CoQ10 group (8% in the supplemented group as compared to 14% in the placebo group). Also, there were significantly more of the CoQ10-treated patients who improved one or more NYHA class than in the group receiving placebo (58% versus 45%). One patient in the CoQ10 group went from NYHA IV to NYHA I during his treatment.