LETTERS TO THE EDITOR
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Constantine Aroneya,
Darryl Burstowa,
Paul Watsona,
Andrew Galbraitha,
Gregory Scaliaa and
Nicholas Betta
a Cardiology Department, The Prince Charles Hospital, Rode Road, Chermside, Brisbane 4032, Australia
We thank Dr. Langsjoen for his interest in our report. He believes that treatment with 100 mg/day of coenzyme Q10 may be inadequate and administered too late in the course of heart failure. In contrast, 11 of 15 studies, including his own (1), of coenzyme Q10 in heart failure used 
100 mg/day, and all but one purported to provide clinical benefit with this dose. He also cites uncontrolled observations (2) that an improvement in New York Heart Association functional class was associated with a higher daily dose of 240 mg (range 75 to 600) and suggests that early in the course of idiopathic dilated cardiomyopathy, patients may respond to treatment with coenzyme Q10 (3). We wonder whether the almost normal baseline left ventricular ejection fraction of 44% of patients early in the course of their disease raises the possibility that for some of them myocardial dysfunction might have been transient, perhaps due to myocarditis. We took care to ensure that our patients had established chronic cardiac failure. Langsjoen’s group (3) also employed 100 mg/day of coenzyme Q10, but more importantly, they used impedance cardiography and systolic time indexes, measurements of left ventricular systolic function that were perhaps appropriate 15 years ago but might now be considered imprecise and obsolete.
We agree that a large, well-conducted and long-term trial of coenzyme Q10 would resolve any remaining uncertainties regarding the efficacy of this agent. At this time, there are no clear data proving its therapeutic effect in heart failure. Therefore, until there is objective contemporary evidence of improvement in myocardial function or survival, it will remain an unproven "alternative" therapy for patients with heart failure. Sadly, as Langsjoen points out, it is difficult to fund and conduct large trials of a "natural and nonpatentable substance" such as coenzyme Q10.
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References
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- Langsjoen PH, Langsjoen AM. Coenzyme Q10 in cardiovascular disease with emphasis on heart failure and myocardial ischaemia. Asia Pac Heart J. 1998;7:160–168[CrossRef]
- Langsjoen H, Langsjoen P, Langsjoen P, Willis R, Folkers K. Usefulness of coenzyme Q10 in clinical cardiology: a long-term study. Mol Aspects Med. 1994;15(Suppl):165–175
- Langsjoen PH, Vadhanavikit S, Folkers K. Response of patients in classes III and IV of cardiomyopathy to therapy in a blind and crossover trial with coenzyme Q10. Proc Natl Acad of Sci USA. 1985;82:4240–4244[Abstract/Free Full Text]
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