Anxiety and P Wave Dispersion in a Healthy Young Population

Abstract

Background: P wave dispersion (P_d), defined as the difference between the maximum (P_max) and the minimum P wave duration (P_min), and P_max are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time. P_d in normal subjects has been reported to be influenced by the autonomic tone, which induces changes in atrial size and the velocity of impulse propagation. However, the association between P_d and anxiety has not been studied in normal subjects. Methods and Results: P_max, P_min and P_d were measured in 726 physically and mentally healthy young male volunteers, aged 21.23 ± 1.25 years (range 20–26). The Spielberger State-Trait Anxiety Inventory (STAI) was scored concomitantly. Blinded intra- and interobserver reproducibility of the P wave duration and P_d measurement were evaluated, and comparison revealed a Pearson correlation coefficient of 0.87 and 0.89 for the P wave duration, and 0.93 and 0.90 for P_d, respectively (p < 0.001). P_max and P_d were significantly correlated with the state anxiety (STAI-1) subscale (r = 0.662, p < 0.001, and r = 0.540, p < 0.001, respectively) and the trait anxiety (STAI-2) subscale (r = 0.583, p < 0.001, and r = 0.479, p < 0.001, respectively). P_min did not show any significant correlation with anxiety. Across 3 variables included in a multiple linear regression analysis, STAI-1 and STAI-2 were the significant independent determinants of P_max and P_d. Beta coefficients indicated that the contribution of STAI-1 to P_max (66.3 and 33.7%) and P_d (65 and 35%) was much greater than that of STAI-2. Conclusions: STAI-1 and STAI-2are associated with an increase in P_max and P_d. The association of P_d resulted from an augmentation of P_max. This is the first study to show the relation between P_max, P_d and anxiety.