The P wave dispersion-one pixel, one millisecond

The electrophysiological activity of the heart is recorded and presented in form of electrocardiogram (ECG). In 1998 the concept of P wave dispersion as the risk factor for atrial fibrillation (AF) recurrence was introduced. It was calculated as the difference between the longest and the shortest P wave. The aim of our study is to prove that the P wave dispersion is an artifact of low accuracy in P wave measurement. The study included 186 patients (78M108F) aged 59.7 +/- 12.9 years, undergoing various electrophysiological procedures. The P wave was measured twice: first, at the paper speed of so m m/s, enhancement 8x (standard- imprecise) and the second time at zoo mm/s, 64-256x (precise). The imprecise measurement method resulted in different duration of all P wave parameters in comparison with precise measurement. The difference between Delta P max and Delta P min indicated a higher value for the latter parameter. It was indicated that the imprecise P wave dispersion value correlated most significantly with the maximal P wave duration, which was measured in a similar way. In contrast with the imprecise measurement method, the minimal and maximal durations of the P waves, being measured accurately, were almost identical. Using precise methodology, the P wave dispersion reaches negligible values and tends to zero. The measurements of the P wave have to be precise to assure the highest scientific and medical sincerity. The highest clinical value is related to the P wave duration.

Automated summary

The study demonstrated that P-wave dispersion is an artifact of low accuracy in P wave measurement, with high precision measurement methods yielding different results compared to imprecise methods.