Background: The prognostic value of P-wave duration has been previously evaluated by signal-averaged ECG (SAECG) in patients with various arrhythmias not associated with acute myocardial infarction (AMI).

Objectives: To investigate the clinical correlates and prognostic value of P-wave duration in patients with ST elevation AMI (STEMI).

Methods: The patients (n=89) were evaluated on the first, second and third day after admission, as well as one week and one month post-AMI. Survival was determined 2 years after the index STEMI.

Results: In comparison with the upper normal range of P-wave duration (< 120 msec), the P-wave duration in STEMI patients was significantly increased on the first day (135.31 ¡À 29.29 msec, P < 0.001), up to day 7 (127.17 ¡À 30.02 msec, P = 0.0455). The most prominent differences were observed in patients with left ventricular ejection fraction (LVEF) ¡Ü 40% (155.47 ¡À 33.8 msec), compared to LVEF > 40% (128.79 ¡À 28 msec) (P = 0.001). P-wave duration above 120 msec was significantly correlated with increased complication rate namely, sustained ventricular tachyarrhythmia (36%), congestive heart failure (41%), atrial fibrillation (11%), recurrent angina (14%), and re-infarction (8%) (P = 0.012, odds ratio 4.267, 95% confidence interval 1.37¨C13.32). P-wave duration of 126 msec on the day of admission was found to have the highest predictive value for in-hospital complications including LVEF < 40% (area under the curve 0.741, P < 0.001).  However, we did not find a significant correlation between P-wave duration and mortality after multivariate analysis.

Conclusions: P-wave duration as evaluated by SAECG correlates negatively with LVEF post- STEMI, and P-wave duration above 126 msec can be utilized as a non-invasive predictor of in-hospital complications and low LVEF following STEMI.