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.