P wave and the development of atrial fibrillation.

Background: Terminal P-wave inversion in lead V(1) representing left atrial overload has been considered a precursor of atrial fibrillation (AF).

Objective: The purpose of this study was to determine whether this P-wave morphologic characteristic can predict the development of AF.

Methods: Digital analysis of 12-lead ECGs was performed to enroll patients with P terminal force > or =0.06 s x 2 mm in lead V(1) from among a database of 308,391 ECG recordings. The prognostic value of ECG characteristics for developing AF was determined.

Results: A total of 78 patients (mean age 52 +/- 19 years) with left atrial overload were chosen from among 102,065 patients in the database. During mean follow-up of 43 months, 15 (19%) patients developed AF (AF group) versus 63 (81%) patients who did not (non-AF group). No significant difference was noted between the AF and non-AF groups with regard to the area, duration, and amplitude of the P-wave terminal portion in lead V(1). In contrast, the area, duration, and amplitude of the P-wave initial portion in the same lead were significantly greater in the AF group than in the non-AF group (114.6 +/- 73.0 microV x ms vs 73.1 +/- 59.3 microV x ms, 42.2 +/- 12.4 ms vs 35.7 +/- 10.1 ms, and 94.0 +/- 39.9 microV vs 68.8 +/- 49.4 microV, respectively; P <.05 for each). Multivariate analysis confirmed that the area of the P-wave initial portion was independently associated with the development of AF (hazard ratio 4.02, 95% confidence interval 1.25-17.8; P = .018).

Conclusion: P-wave initial portion in lead V(1) was an independent risk stratifier of AF development in patients with marked left atrial overload.