Diagnostic Utility of P-Wave Duration in Identifying Left Atrial Enlargement: Insights from the ELSA-Brasil Cohort.

BACKGROUND: Atrial cardiomyopathy encompasses various atrial abnormalities, including left atrial enlargement (LAE), which is associated with adverse cardiovascular and neurocognitive outcomes. P-wave duration ≥120 ms on 12-lead electrocardiogram (ECG) is a widely available, cost-effective tool and one of the main diagnostic criteria adopted. However, its diagnostic performance in large-scale studies remains underexplored. OBJECTIVES: To evaluate the correlation between P-wave duration and left atrial volume (LAV) measured by transthoracic echocardiogram (TTE) and determine the diagnostic accuracy of P-wave duration ≥120 ms for identifying LAE. METHODS: We conducted a cross-sectional analysis of baseline data from the ELSA-Brasil cohort participants in sinus rhythm. P-wave duration was automatically measured via standard 12-lead ECG, with ≥120 ms indicating enlargement. LAE was defined as LAV>34 mL/m2 by TTE. Spearman's rank test assessed correlation. Diagnostic performance metrics - sensitivity (Sn), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV), positive and negative likelihood ratio (LR+ and LR-) - were calculated. Also, a Receiver Operating Characteristic (ROC) was constructed. Statistical significance was set at p-value<0.05 with 95% confidence interval. RESULTS: The study included 2589 participants, 419 (16,1%) with LAV index>34 mL/m2. P-wave duration correlated weakly with LAV (Spearman's ρ = 0.120, p < 0.001). Diagnostic accuracy measurements were AUC = 0.557 ± 0.032; Sn = 0.296; Sp = 0.811; PPV = 0.232; NPV = 0.856; LR+ 1.566; LR- 0.868. CONCLUSION: P-wave duration demonstrates limited diagnostic value for identifying LAE, suggesting against its recommendation as a standalone diagnostic criterion for this condition.