title: Lack of effect of coenzyme Q on left ventricular function in patients with congestive heart failure.
abstract: OBJECTIVE
  This study evaluated the effects of oral therapy with coenzyme Q on echocardiographic and hemodynamic indexes of left ventricular function and on quality of life in patients with chronic left ventricular dysfunction.
  
  
  BACKGROUND
  Coenzyme Q is a coenzyme for oxidative phosphorylation and an antioxidant and free radical scavenger. It has been claimed to improve symptoms, quality of life, left ventricular ejection fraction and prognosis in patients with cardiac failure.
  
  
  METHODS
  Thirty patients with ischemic or idiopathic dilated cardiomyopathy and chronic left ventricular dysfunction (ejection fraction 26 +/- 6%) were randomized to a double-blind crossover trial of oral coenzyme Q versus placebo, each for 3 months. Right heart pressures, cardiac output and echocardiographic left ventricular volumes were measured at baseline and after each treatment phase, and quality of life was assessed using the Minnesota "Living With Heart Failure" questionnaire. It was calculated that to demonstrate an increase in left ventricular ejection fraction from 25% to 30% with a standard deviation of 5% using 95% confidence intervals with a power of 80% we would require 17 patients.
  
  
  RESULTS
  Twenty-seven completed both treatment phases. There was no significant difference in left ventricular ejection fraction, cardiac volumes or hemodynamic and quality of life indices after treatment with coenzyme Q or placebo, although plasma coenzyme Q levels increased from 903 +/- 345 nmol/l(-1) to 2,029 +/- 856 nmol/l(-1).
  
  
  CONCLUSIONS
  In patients with left ventricular dysfunction, treatment for three months with oral coenzyme Q failed to improve resting left ventricular systolic function or quality of life despite an increase in plasma levels of coenzyme Q to more than twice basal values.
authors.affiliation: Department of Cardiology, The Prince Charles Hospital, University of Queensland, Brisbane, Australia.
authors.forename: P S
authors.initials: PS
authors.lastname: Watson
authors.forename: G M
authors.initials: GM
authors.lastname: Scalia
authors.forename: A
authors.initials: A
authors.lastname: Galbraith
authors.forename: D J
authors.initials: DJ
authors.lastname: Burstow
authors.forename: N
authors.initials: N
authors.lastname: Bett
authors.forename: C N
authors.initials: CN
authors.lastname: Aroney
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D002908:Chronic Disease; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004452:Echocardiography / Q000187:drug effects; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D013318:Stroke Volume / Q000187:drug effects; D017211:Treatment Failure; D014451:Ubiquinone / Q000008:administration & dosage* / Q000009:adverse effects; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy; D016277:Ventricular Function, Left / Q000187:drug effects*
chemical_list: D014451:Ubiquinone