The Q-Symbio study was an international multi-center clinical trial that was reported in the Journal of the American College of Cardiology: Heart Failure in September 2014.[1]
Professor Mortensen and a team of researchers enrolled 420 patients with moderate to severe chronic heart failure. Half of the patients received a Coenzyme Q10 treatment of 100 milligrams three times daily for two years. The other half of the patients got inactive placebo capsules daily for two years. All of the patients continued their standard heart failure medications.[1]
Not until the end of the clinical trial did the researchers and the patients find out which patients were receiving the active Coenzyme Q10 treatment and which patients were receiving the placebo treatment.
The patients in the Coenzyme Q10 treatment group had significantly reduced risk of heart disease death and death from all causes and significantly fewer hospital stays for heart failure complications.[1]
A later sub-analysis including only the European segment of the Q-Symbio Study showed that the Coenzyme Q10 therapy was also positively associated with a significant improvement in ejection fraction. The results of the Coenzyme Q10 treatment were even more impressive in the European sub-study. Treatment with Coenzyme Q10 300 milligrams per day in addition to conventional heart failure medications was safe, well tolerated, and effective at reducing symptoms and improving survival rates of chronic heart failure patients.[2]
:6 was invoked but never defined (see the help page).