Dispersion of P wave duration and P wave vector in patients with atrial septal aneurysm

Aims Atrial septal aneurysm (ASA) may be involved in the genesis of atrial arrhythmias as a consequence of disturbances in the propagation of depolarization, which may be easily assessed by P wave dispersion measurement. The aim of this study is to assess the dispersion of P wave duration and P wave vector in patients with ASA and to determine the effect of associated interatrial shunt on the magnitude of P wave dispersion.

Methods and results The study population consisted of 23 healthy volunteers and 88 patients with ASA base more than 15 mm and protrusion more than 7.5 mm. The size of aneurysms and atria was determined by echocardiography and P wave dispersion was measured on the surface ECG. In ASA patients, dispersion of P wave duration was significantly increased when compared with healthy controls (7.8 ± 12.1 vs. 3.7 ± 3.5 ms; P < 0.01). Dispersion of P wave vector was also significantly increased (8.5 ± 10.1° vs. 4.6 ± 3.6°; P < 0.005). In healthy volunteers, the mean values of both parameters were below the cutoff points.

Conclusion In patients with ASA, there was a significant dispersion of P wave duration and P wave vector. Variation in P wave duration was significantly correlated with the dispersion of P wave vector and age of these patients. Dispersion of P wave vector was significantly decreased in ASA patients with interatrial shunt. P wave dispersion in ASA patients may predispose to the development of atrial arrhythmias.