Anxiety and P wave dispersion in a healthy young population

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-2 are 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.