Cholesterol paradox in patients with paroxysmal atrial fibrillation

Hypercholesterolemia is a major risk factor for coronary heart disease (CHD), but the associations among lipids, lipoproteins and paroxysmal atrial fibrillation (PAF) have not yet been reported. The associations among lipids, lipoproteins and PAF were examined in a case-control study, in which cases and controls were defined as those with/without definite ECG-detectable PAF, respectively. CHD patients were excluded from the study. The mean values of serum total cholesterol (TC), triglyceride (TG) and high density lipoprotein-cholesterol (HDL-C), after adjusting for age and gender, in patients with PAF were lower than those in patients without PAF (175 +/- 4 mg/dl vs. 190 +/- 3 mg/dl, 104 +/- 7 mg/dl vs. 123 +/- 6 mg/dl, 46.0 +/- 1.7 mg/dl vs. 51.8 +/- 1.4 mg/dl, respectively), as assessed by an analysis of covariance. After controlling for age and gender, TC, TG and HDL-C (all in quartiles) were inversely and linearly (p < 0.05) associated with the percentage of patients with PAF, as assessed by a multiple logistic regression analysis. The associations between TC or TG and PAF varied with the HDL-C level: significant when HDL-C was low (p < 0.05), but not when HDL-C was high. The odds ratio (relative risk of PAF) for patients with both low TC or TG and low HDL-C was 4.08 (95% CI: 1.81-9.57) times or 9. 40 (3.25-32.0) times higher (p < 0.01) than that for patients with high TC or TG and high HDL-C, respectively. In conclusion, low serum levels of TC and TG were found in PAF patients, while reduced HDL-C may cause PAF. Hypolipoproteinemia including low HDL-C may affect atrial vulnerability and cause atrial fibrillation.