INTRODUCTION: Increased sympathetic nerve activity has been suggested in patients with chronic kidney disease (CKD). Pathologic sympathetic activity can alter heart rate variability (HRV), and the altered HRV has prognostic importance, so that reducing sympathetic activity may be an important strategy. Novel nonlinear HRVs, including deceleration capacity (DC), have greater predictive power for mortality. We have recently proposed an increase in a non-Gaussianity index of HRV, lambda(25s), which indicates the probability of volcanic heart rate deviations of departure from each standard deviation level, as a marker of sympathetic cardiac overdrive. L/T-type calcium channel blocker (L/T-CCB), azelnidipine, decreases sympathetic nerve activity in experimental and clinical studies. METHODS: In 43 hypertensive patients with CKD under treatment with an angiotensin receptor blocker (ARB), we investigated whether 8-week add-on L/T-CCB treatment could restore HRV. RESULTS: Means of all normal-to-normal intervals over 24 h (p<0.0001) and DC (p=0.002) increased, and lambda(25s) (p=0.001) decreased regardless of gender, age, renal function or blood pressure, while no significant changes were observed in the other HRVs. CONCLUSIONS: Reduction of lambda(25s) is useful to assess the effect of sympathoinhibitory treatment. Further studies are needed to investigate if the restoration of HRV is directly associated with the improvement of prognosis in patients with CKD.