Automatically assessed P-wave predicts cardiac events independently of left atrial enlargement in patients with cardiovascular risks: The Japan Morning Surge-Home Blood Pressure Study

A prolonged P-wave in electrocardiography (ECG) reflects atrial remodeling and predicts the development of atrial fibrillation (AF). The authors enrolled 810 subjects in the Japan Morning Surge Home Blood Pressure (J-HOP) study who had ≥1 cardiovascular (CV) risk factor. The duration of P-wave was automatically analyzed by standard 12-lead electrocardiogram. Left atrial (LA) enlargement and left ventricular hypertrophy (LVH) were measured on echocardiography. The primary end points were fatal/nonfatal cardiac events: myocardial infarction, sudden death, and hospitalization for heart failure. The maximum P-wave duration (Pmax) from the 12 leads was selected for analysis. The authors compared four prolonged P-wave cutoffs (Pmax = 120, 130, 140, 150 ms) and cardiac events. LA diameter and left ventricular mass index (LVMI) were significantly associated with Pmax (r = 0.08, P =.02 and r = 0.17, P <.001, respectively). When the cutoff level was Pmax 120 or 130 ms, prolonged P-wave was not associated with cardiac events (P =.45 and P =.10), but when a prolonged P-wave was defined as Pmax ≥ 140 ms (n = 50) or Pmax ≥ 150 ms (n = 19), the patients in those groups had significantly higher incidence of cardiac events than others (P <.001 and P =.03). A Cox proportional hazards model including age, gender, body mass index, smoking, regular drinker, hypertension, dyslipidemia, diabetes, office systolic blood pressure, heart rate, LA enlargement, and LVH revealed that prolonged P-wave defined as Pmax ≥ 140 ms was independently associated with cardiac events (hazard ratio: 4.23; 95% confidence interval: 1.30–13.77; P =.02). In conclusion, the automatically assessed prolonged P-wave was associated with cardiac events independently of LA enlargement and LVH in Japanese patients with CV risks.