Statins reduce mortality in patients with coronary heart disease (CHD). An antiarrhythmic effect of statins has been suggested and reported as a possible contributing mechanism. The aim of this study was to examine whether atorvastatin had any effect on heart rate variability (HRV), an important predictor of sudden cardiac death. Eighty patients previously treated with coronary artery bypass grafting (CABG) were studied. The study was designed as a randomized, placebo-controlled, double blinded crossover study. The patients were randomized in two groups, and were treated with 80 mg atorvastatin or placebo for 6 weeks before crossing over to the opposite treatment for another 6 weeks. There was no washout between treatments. Twenty-four-hour Holter recording and plasma lipids and lipoprotein measurements were performed at baseline and after each 6-week period. There was no change in HRV indices after treatment with 80 mg atorvastatin for 6 weeks. A significant reduction in total cholesterol (46%, p</=0.001), LDL cholesterol (61%, p</=0.001) and triglycerides (35%, p</=0.001) were observed during treatment with atorvastatin. Therapy with 80 mg atorvastatin daily for 6 weeks reduced total cholesterol, LDL cholesterol and triglycerides significantly, while there was no effect on 24-h HRV indices. The study therefore does not lend support for any effect of atorvastatin on HRV after 6 weeks of treatment in patients treated with CABG.