Notched P-wave on digital electrocardiogram (ECG) was shown to be linked with cardiovascular events and left atrial enlargement.

• In this study of 810 individuals from the J-HOP Study who had one or more cardiovascular risk factors, the association between notched P-wave characteristics on digital ECG and long-term cardiovascular events was examined.

• Post-adjustment for age, gender, and comorbidity, a notched P-wave was identified as a significant predictor of cardiovascular events (hazard ratio: 1.83), when a notched P-wave was defined as ≥20 ms in the M shape (n=92).

• When a notched P-wave was defined as ≥40 ms in the M shape (n=25), the hazard ratio of cardiovascular events in the notched P-wave group was not significant post- adjustment for covariates (hazard ratio: 1.52).

• In the notched P-wave group (peak-to-peak distance of ≥20 ms in the M shape), significantly higher left atrial diameter and left ventricular mass index (LVMI) were detected compared to the control group (left atrial diameter: 38.8±5.9 vs 36.8±5.0 mm; LVMI: 103.9±27.7 vs 96.3±25.7 g/m2).