Abstract: AIM: To study the effects of irbesartan on blood pressure and heart rate variability ( HRV) in patients with essential hypertension ( EH). METHODS: 40 patients with EH received 150-300 mg·d^-1 irbesartan for 8 weeks. The changes in blood pressure were assessed. The time-and frequency-domain measurements of HRV from 24 hours ambulartory electrocardiographyic recordings were analyzed in 35 healthy controls and in patients with EH before and after the treatment. RESULTS: Compared to baseline, the systolic and diastolic blood pressure decreased from 21. 62 ±0. 47/12. 01 ± 0. 32 kPa to 18. 90 ±0. 32/8. 01 ±2. 35 kPa in the irbesartan groups, and respond rates were 73. 1 %.Compared with controls, the standard deviation of normal-to-normal intervals (SDNN), rate-mean-square of the differences of successive RR intervals ( RMSSD), the percentage of RR intervals differing >50 ms ( PNN50 ) and the high frequency ( HF) in patients with EH were decreased, While the ratio between low frequency and high frequency ( LF/ HF) were increased. After the treatment of irbesartan, the values of SDNN, RMSSD, PNN50, and HF were increased, and the LF/HF was decreased significantly. CONCLUSION: Irbersartan can increase the lowed HRV in patients with EH, which improves the cardiovascular automatic function.

Key words: irbesartan, essential hypertension, heart rate variability