The prognostic importance of isolated P-Wave abnormalities.

Background: While certain P-Wave morphologies have been associated with abnormal atrial size and either pulmonary or cardiovascular (CV) disease, their relationship to mortality and specific cause of death has not been reported.

Methods: Analyses were performed on the first digitally recorded electrocardiogram (ECG) on 43 903 patients at the Palo Alto Veterans Administration Medical Center since 1987. After appropriate exclusions, 40 020 patients remained. Using computerized algorithms, P-wave amplitude and duration in 12 leads as well as several standardized ECG interpretations were extracted. The main outcome measures were pulmonary and CV mortality.

Results: During a mean follow-up of 6 years there were 3417 CV and 1213 pulmonary deaths. After adjusting for age and heart rate in a Cox regression model, P-wave amplitude in the inferior leads was the strongest predictor of pulmonary death (hazard ratio [HR]: 3.0, 95% confidence interval [CI]: 2.3-3.9, P < .0001 for an amplitude > 2.5 mm), outperforming all other ECG criteria. The depth of P-wave inversion in leads V(1) or V(2) and P-wave duration were strong predictors of CV death (HR: 1.7, 95% CI: 1.5-2.0, P < 0.0001 for a P-wave inversion deeper than 1 mm), outperforming many previously established ECG predictors of CV death.

Conclusions: P-wave amplitude in the inferior leads is the strongest independent predictor of pulmonary death while P-wave duration and the depth of P-wave inversion in leads V(1) or V(2) significantly predict CV death. These measurements can be obtained easily and should be considered as part of clinical risk stratification.