P-Wave Morphology, Amplitude, Duration and Dispersion in Atrial Arrhythmias

Abstract

The detailed analysis of the P-wave duration and dispersion by means of conventional electrocardiography with the 12 standard surface leads in the stratification of patients suffering from AF is a recognized universal approach. P-wave dispersion (PWD) has received increasing attention in the field of non-invasive electrophysiology studying atrial arrhythmias and has been examined in a broad range of clinical settings including cardiovascular and non-cardiovascular diseases. It is well accepted that, not only the P-wave duration, but also the P-wave morphology and dispersion have the potential to give information about the anatomical substrate predisposing to AF. Patients with diseased atrial myocardium with fibrotic changes may develop abnormal electrophysiological alterations. Therefore, these atrial anisotropic characteristics may play an important role in creating reentry circuits by causing inhomogeneous and discontinuous propagation of the impulse in the atrial tissue. The altered atrial myocardium may generate unidirectional block, conduction delay and reentrant atrial rhythms. The P-wave of the electrocardiogram may show alterations that can be associated with atrial arrhythmias and AF. PWD is considered a noninvasive electrocardiographic marker for atrial remodeling and predictor for AF. It has been shown that increased P-wave duration and PWD reflect prolongation of intra-atrial and inter-atrial conduction time. In patients prone to develop atrial arrhythmias and AF, PWD reflects prolonged, inhomogeneous and anisotropic distribution of connections between myocardial fibers resulting in discontinuous anisotropic propagation of sinus impulses and atrial conduction. PWD is considered as a sensitive and specific ECG marker and predictor of atrial arrhythmias and paroxysmal AF.