Increased variance of P wave duration on the electrocardiogram distinguishes patients with idiopathic paroxysmal atrial fibrillation

We hypothesized that the variance of P wave duration (P variance) in the 12 -lead ECG could reflect the spatial dispersion of P wave duration due to in homogeneous and delayed propagation of sinus impulses in the atria, and mor eover could present better reproducibility than maximum P wave duration and P wave dispersion that have already been used for the prediction of idiopa thic paroxysmal AF. We also tested a semiautomated PC-based method to impro ve the accuracy and reproducibility of P wave measurements. A 12-lead ECG w as obtained from 60 patients with idiopathic paroxysmal AF and from 50 heal thy controls. All ECGs were analyzed manually using magnifying lens and cal ipers, while 20 randomly selected ones were scanned and analyzed on screen using common commercial software. P maximum, P dispersion, and P variance w ere all significantly higher in patients with paroxysmal AF than in control s. A P maximum value of 110 ms, a P dispersion value of 40 ms, and a P vari ance value of 120 ms(2) separated patients from controls with a sensitivity of 88%, 83%, and 80%, respectively and a specificity of 75%, 85%, and 74%, respectively. The reproducibility of P variance was higher compared to P d ispersion and P maximum. Finally, the PC-based method significantly increas ed accuracy and reproducibility of P wave measurements. Thus, the variance of P wave duration could be a useful ECG marker for the prediction of parox ysmal idiopathic AF and the use of PC-based methods may enhance the accurat e measuring of P wave duration on the ECG.