P-wave dispersion (Pd), defined as the difference between the maximum and the minimum P-wave duration (Pmin) and maximum P-wave duration (Pmax) are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time, respectively. Pd 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 Pd and anxiety has not been studied in normal subjects.
Pmax, Pmin and Pd were measured in 726 physically and mentally young healthy 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 Pd measurement were evaluated, and comparision revealed a Pearson correlation coefficient of 0.87 and 0.89 for the P-wave duration, 0.93 and 0.90 for Pd, respectively (p<0.001). Pmax and Pd were significantly correlated with the STAI-1 subscale (State Anxiety Scale) (r = 0.662, p<0.001; r = 0.540, p<0.001, respectively) and STAI-2 subscale (Trait Anxiety Scale) (r = 0.583, p<0.001; r = 0.479, p<0.001, respectively). Pmin didn’t 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 Pmax and Pd. Beta coefficients indicated that the contribution of STAI-1 was much more than STAI-2 on Pmax (66.3%, 33.7%, respectively) and Pd (65%, 35%, respectively).
The State Anxiety Scale and The Trait Anxiety Scale is associated with an increase in Pmax and Pd. Association of Pd resulted from augmentation of Pmax. This is the first study to show relation between Pmax, Pd and anxiety.
The stimulation of sympathetic nervous system during anxiety may be the underlying mechanism of prolonged of Pmax and Pd. Extrapolating from these findings, our results point to a cardiac autonomic imbalance in patients with anxiety.
Huseyin Uyarel, None.