Four main studies can be found in support of CoQ10 supplementation in Congestive heart failure(CHF). Also be aware that any form of heart failure is thought to be due to mitochondrial disfunction and when these power house units are optimized, function improves.

Coenzyme Q10 Terclatrate And Creatine In Chronic Heart Failure: A Randomized, Placebo-controlled, Double-blind Study 

Change of Effect Increase
Trial Design Double blind
Trial Length n/a
Number of Subjects 67
Gender n/a

Notes for this study:
A water-soluble form of CoQ10 (terclatrate) at 320mg daily was able to, alongside 340mg creatine monohydrate, able to increase physical work capacity in patients after Chronic Heart Failure.


A Randomized Trial Of Coenzyme Q10 In Mitochondrial Disorders

Change of Effect Increase
Trial Design Double blind
Trial Length n/a
Number of Subjects 30
Gender n/a

Notes for this study:
30 patients with mitochondrial cytopathy were given 1200mg CoQ10 daily for 60 days in a double-blind crossover manner.

Increased VO2 max and attentuated of lactate production were noted, indicating improved exercise capacity.

Strength, body composition, and quality of life unaffected.


Coenzyme Q10 And Exercise Training In Chronic Heart Failure

Change of Effect Increase
Trial Design Double blind
Trial Length n/a
Number of Subjects 23
Gender n/a

Notes for this study:
In persons with chronic heart failure, CoQ10 at 300mg daily (in three divided dosages) was able to increase functional capacity and endothelial function after 4 weeks of supplementation.

Benefits of CoQ10 on one of the parameters of heart health (systolic wall thickening index) was synergistic with exercise.


Coenzyme Q10 (CoQ10) In Isolated Diastolic Heart Failure In Hypertrophic Cardiomyopathy (HCM)

Change of Effect Increase
Trial Design Cohort
Trial Length 6+ Months
Number of Subjects 41
Gender Both Genders
Ages 18-29, 30-44, 45-64, 65+

Notes for this study:
200mg CoQ10 daily alongside standard therapy (same in both groups) in persons with cardiohypertrophy was able to improve left ventricle and heart function while reducing the size of the left ventricle. Time of trial varied (9.4-27.5 months, mean length over a year)