Premature atrial contractions in the general population: frequency and risk factors.

BACKGROUND: Premature atrial contractions (PACs) are independent predictors of atrial fibrillation, stroke, and death. However, little is known about PAC frequency in the general population and its association with other cardiovascular risk factors. METHODS AND RESULTS: We performed a cross-sectional analysis among participants of the population-based Swiss cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA). 24-hour Holter electrocardiograms to assess PAC prevalence and frequency were performed in a random sample of 1742 participants aged ≥50 years. The median (interquartile range) number of PACs per hour was 0.8 (0.4-1.8), 1.1 (0.5-2.4), 1.4 (0.7-4.6), 2.3 (0.8-6.9), and 2.6 (1.2-6.5) among participants aged 50 to 55, 55 to 60, 60 to 65, 65 to 70, and ≥70 years, respectively (P<0.0001). Only 18 (1.0%) participants did not have at least 1 PAC during Holter monitoring. In multivariable negative binomial regression models, PAC frequency was significantly associated with age (risk ratio [RR] per SD 1.80; P<0.0001), height (RR per SD 1.52; P<0.0001), prevalent cardiovascular disease (RR 2.40; P<0.0001), log-transformed N-terminal pro B-type natriuretic peptides (RR per SD 1.27; P<0.0001), physical activity ≥2 hours per day (RR 0.69; P=0.002), and high-density lipoprotein cholesterol (RR per SD 0.80; P=0.0002). Hypertension and body mass index were not significantly related to PAC frequency. CONCLUSIONS: To our knowledge, this is the first study to assess risk factors for PAC frequency in the general population aged ≥50 years. PACs are common, and their frequency is independently associated with age, height, history of cardiovascular disease, natriuretic peptide levels, physical activity, and high-density lipoprotein cholesterol. The underlying mechanisms of these relationships need to be addressed in future studies.