C015: Circadian variation of pulse pressure and heart rate variability in patients with essential hypertension

To evaluate the circadian variation of pulse pressure (PP) and heart rate variability (HRV) in essential hypertension (HTN), we performed 48-hr. ambulatory blood pressure (BP) monitoring (Colin, Japan) every 30 min. and Holter ECG recording (Del Mar Avionics, USA) in 56 untreated patients with mild to moderate HTN. Power spectral analysis of RR interval was performed from 24-hr. Holter ECG every 10 min. by the FFT method to obtain the low frequency band (LF:0.04–0.15Hz) and the high frequency band (UF: 0.15–0.40Hz). The nocturnal reduction rate (NRR) of PP was calculated according to the formula. NRR(%) = (daytime mean − nighttime mean) / (daytime mean). Mean BP and PP for 48 hrs. were 142±14 / 84±11, 65±9 mmHg, respectively. Both 24-hr. mean LF and HF correlated with 48-hr. mean PP (r = −0.30, −0.32; p