Cardiac arrhythmias and left ventricular hypertrophy in dipper and nondipper patients with essential hypertension

To evaluate the behavior of cardiac arrhythmias in dipper and nondipper hypertensive patients, 48-h ambulatory blood pressure monitoring, 24-h Holter electrocardiogram recording and echocardiographic studies were performed in 56 untreated outpatients with essential hypertension. These patients were divided into 2 groups according to the presence (dipper, n = 33) or absence (nondipper, n = 23) of reduction of both systolic and diastolic blood pressure during nighttime by an average of more than 10% of daytime blood pressure. Mean 48-h systolic and diastolic blood pressures did not differ between the 2 groups. Nondipper patients had a significantly larger left atrial dimension (31.9 +/- 3.8 vs 35.6 +/- 3.7mm; p < 0.01), left ventricular mass index (114 +/- 26 vs 136 +/- 36 g/m(2); p < 0.05), as well as a larger number of total supraventricular (16 +/- 19 vs 89 +/- 197 beats; p < 0.05) and ventricular ectopic beats (7 +/- 14 vs 47 +/- 96 beats; p < 0.05) during daytime as compared with dippers. In conclusion, nondipper hypertensive patients an likely to experience supraventricular and ventricular arrhythmias more frequently than dippers, A blunted nocturnal blood pressure fall may be involved in the appearance of cardiac arrhythmias in patients with essential hypertension.