Effect of Obesity on P-Wave Parameters in a Chinese Population

Methods: The study population consisted of 40 obese (body mass index (BMI) >= 25 Kg/m2, according to the World Health Organization classification for the Asian population) subjects and 20 age- and sex-matched normal weight controls. Maximum P-wave duration (P(max)), minimum P-wave duration (P(min)), and P(d) were carefully measured using a 12-lead electrocardiogram, while the presence of interatrial block (IAB; P >= 110 ms) was assessed. Results: There were no significant differences between the two groups regarding age, sex, history of hypertension or diabetes, and hyperlipidemia. Compared to controls, BMI, left atrial diameter (LAD), and interventricular septal thickness were increased, while P(max) (111.9 +/- 9.3 vs 101.1 +/- 6.0 ms, P < 0.01) and P(d) (47.9 +/- 9.3 vs 31.8 +/- 6.9 ms, P < 0.01) were significantly prolonged in the obese group. P(min) was similar between the two groups. The prevalence of IAB was significantly greater in the obese subjects. Pearson's correlation analysis showed that there were positive correlations between P(d) and BMI (r = 0.6, P < 0.001), as well as between P(d) and LAD (r = 0.366, P < 0.05). Conclusion: Our data suggest that obesity is associated with increased P(max) and P(d), and increased prevalence of IAB, parameters that have been associated with atrial fibrillation. The correlation of these electrocardiogram parameters with LAD indicates an association between increased BMI and atrial remodeling in Asian subjects. Ann Noninvasive Electrocardiol 2010;15(3):259-263.