Israel Medical Association Journal

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.

Background: Familial dysautonomia is a hereditary disease characterized by dysfunction of the sensory and autonomic nervous systems. Studies in patients with familial dysautonomia have shown that abnormal cardiac autonomic denervation might influence repolarization. Autonomic tone also affects atrial conduction parameters and P-wave dispersion, which are predictive of atrial fibrillation.

Objectives: To examine the possible association of familial dysautonomia with abnormal atrial conduction and P-wave dispersion.

Methods: The study population included 12 patients with familial dysautonomia and age and sex-matched control subjects. All participants underwent a 12-lead electrocardiogram under strict conditions. P-wave lengths and P-wave dispersion were computed from a randomly selected beat and an averaged beat using designated computer software.

Results: There were no statistically significant differences between the groups in minimal, maximal, and average P-wave duration or P-wave dispersion for a randomly selected beat. P-wave dispersion for an averaged beat was also similar. During 6 months follow-up, no supraventricular arrhythmias were documented in either group.

Conclusions: We found that patients with familial dysautonomia had P-wave dispersion parameters not significantly different from those of controls. Further research is required to clarify the effects of dysautonomia on atrial conduction in familial dysautonomia.