The P-wave in the electrocardiogram of hypertensive patients before and after therapy

P-wave areas in the electrocardiogram (ECG) of 51 patients with hypertension and of 53 normotensive controls were measured in lead V1 using a computerised planimeter. The total area (in mm2) of P-waves was significantly larger in hypertensives than in normotensives, i.e. males 0.59 vs 0.31; females 0.55 vs 0.26 (p less than .0001) respectively. With exception of one male, the P-waves in hypertensives were either negative or biphasic with terminal negativity. In part 2 of the study, P-wave areas of 84 hypertensives were measured prior to and five years after treatment. The patients had no previous antihypertensive therapy, a diastolic blood pressure (DBP) 90-104 mmHg at the onset of the study, no ECG signs of left ventricular hypertrophy (LVH), and DBP less than 85 mmHg at the end of the trial. After five years, the mean values of the P-wave areas (in mm2) decreased in white males from 0.67 to 0.36; in white females from 0.63 to 0.42; in black males from 0.97 to 0.56; and in black females from 0.80 to 0.46. We conclude that ECG P-wave area is significantly larger in untreated hypertensives compared with normotensives. In successfully treated hypertensives, the P-wave area returns to normal values.