P Wave Dispersion: A Valuable Non-Invasive Marker of Vulnerability to Atrial Arrhythmias

Abstract

The prolongation of intraatrial and interatrial conduction time and the non-homogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation (AF). Previous studies have demonstrated that individuals with clinical history of paroxysmal AF show a significantly increased P wave duration in 12-lead surface electrocardiograms (ECG) and signal-averaged ECG recordings. The inhomogeneous and discontinuous atrial conduction in patients with atrial arrhythmias has been studied, during the last years, with a new ECG index, P wave dispersion. P wave dispersion is defined as the difference between the longest and the shortest P wave duration recorded from multiple different surface ECG leads. Extensive clinical evaluation of P wave dispersion has been performed in the assessment of the risk for AF in patients without apparent heart disease, in hypertensive patients, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. P wave dispersion has proven to be a sensitive and specific ECG predictor of AF in the various clinical settings. However, the methodology used for the calculation of P wave dispersion has not been standardized so far and more efforts to improve the reliability and reproducibility of P wave dispersion measurements are needed. In conclusion, P wave dispersion constitutes a significant contribution to the field of non-invasive electrocardiology and seems to be quite promising in the field of AF prediction.