Ubiquinone (coenzyme Q10) in the long-term treatment of idiopathic dilated cardiomyopathy.

Using a placebo-controlled, double-blind cross-over study the potential therapeutic effect of ubiquinone (coenzyme Q10) was investigated in 25 patients suffering from idiopathic dilated cardiomyopathy (New York Heart Association functional classification I, II and III). Over an initial period of 4 months, 15 patients were administered verum (3 x 33.3 mg coenzyme Q10 x day-1 p.o.) and subsequently given a placebo during the ensuing 4 months (V/P). The sequence of treatment was reversed within the remaining 10 patients (P/V). Therapeutic efficacy was assessed by means of echocardiogram, chest X-ray, radionuclide ventriculography in combination with exercise test and impedance cardiography. Control values for left ventricular function parameters were similar in both groups; left ventricular ejection fraction: 39.5 +/- 11.5% (P/V), 37.6 +/- 17.0% (V/P); left ventricular end-diastolic diameter: 65 +/- 9 mm (P/V), 67 +/- 8 mm (P/V); and cardiac output: 5.1 +/- 1.41 x min-1 (P/V), 5.1 +/- 1.11 x min-1 (V/P). Chronic treatment with ubiquinone had no influence on haemodynamic parameters, electrocardiogram, incidence of ventricular arrhythmias or on exercise tolerance. It was therefore impossible to demonstrate any therapeutic effect of ubiquinone in patients suffering from idiopathic dilated cardiomyopathy.