OBJECTIVE: To investigate the relationship of reversal of hypertensive left ventricular hypertrophy (LVH) with heart rate variability (HRV) and smoothness index (SI). METHODS: A total of 127 patients with untreated essential hypertension associated with LVH were enrolled to receive a 20-week treatment. The drugs included losartan potassium & hydrochlorothiazide (1 tablet/day) and metoprolol (12.5 mg - 50 mg twice daily). The sitting systolic and diastolic blood pressures (SBP & DBP), M-mode and pulsed Doppler echocardiography, 24-hour ambulatory blood pressure monitoring (ABPM) and 24-hour ambulatory ECG (Holter) were performed at pre- and post-treatment. The changes in various parameters such as echocardiography left ventricular end-systolic dimension (LVDs), left ventricular end-diastolic dimension (LVDd) and the thickness of interventricular septum (IVST) and posterior wall (PWT) were measured. And left ventricular mass index (LVMI) and smoothness index (SI) were also examined. The evaluated parameters of ABPM were average 24-hour, daytime and nighttime SBP & DBP. As to 24-hour ambulatory ECG (Holter), the parameters were standard deviation of normal to normal intervals (SDNN), rate mean square of the differences of successive RR intervals (RMSSD), percentage of RR intervals differing > 50 ms (PNN50), high frequency (HF) and low frequency (LF). RESULTS: After a 20-week treatment, the levels of sitting blood pressure (SBP 158.72 +/- 12.11 mm Hg vs 132.21 +/- 14.03 mm Hg; DBP 97.20 +/- 7.71 vs 86.36 +/- 6.48 mm Hg, P < 0.001), parameters of 24-hour ABPM (24-hour mean SBP 146.20 +/- 10.11 mm Hg vs 129.68 +/- 6.12 mm Hg, P < 0.001; 24-hour mean DBP 93.45 +/- 5.46 mm Hg vs 81.77 +/- 6.71 mm Hg, P < 0.01; daytime mean SBP 149.53 +/- 8.67 mm Hg vs 133.60 +/- 6.27 mm Hg, P < 0.001; daytime mean DBP 94.68 +/- 4.96 mm Hg vs 83.55 +/- 7.03 mm Hg, P < 0.001; nighttime mean SBP 137.21 +/- 8.73 mm Hg vs 122.74 +/- 7.58 mm Hg, P < 0.001; nighttime mean DBP 86.75 +/- 6.22 mm Hg vs 72.81 +/- 5.47 mm Hg, P < 0.001) and LVMI significantly decreased (128.90 +/- 32.35 g/m(2) vs 118.39 +/- 31.10 g/m(2), P < 0.01) while the indicators of HRV changes such as SDNN, RMSSD, PNN50 and HF significantly increased (SDNN 97.28 +/- 16.67 ms vs 152.27 +/- 34.23 ms, P < 0.01; RMSSD 21.32 +/- 8.70 ms vs 41.91 +/- 10.38 ms, P < 0.001; PNN50 3.17 +/- 1.23 vs 5.89 +/- 2.18, P < 0.01; HF 239.82 +/- 98.26 ms(2)/Hz vs 367.32 +/- 188.37 ms(2)/Hz, P < 0.01)accompanied by the decreases in LF and LF/HF (LF 485.22 +/- 217.34 ms(2)/Hz vs 287.94 +/- 128.61 ms(2)/Hz, P < 0.01; LF/HF 2.03 +/- 0.56 vs 0.79 +/- 0.38, P < 0.001). The post-treatment SIs of SBP and DBP were 1.35 and 1.2 respectively. CONCLUSION: The combination treatment of angiotensin II receptor blocker (ARB), diuretics and beta1-receptor blockers can lower the blood pressures stably, improve heart rate variability and lead to a reversal of hypertensive LVH.