Unilateral renal denervation (DNx) improves autonomic balance in conscious rabbits with chronic heart failure (CHF)

Abstract

A hallmark of CHF is autonomic imbalance with increased sympathetic tone. Renal DNx in CHF patient trials has proven beneficial, but the protective mechanisms remain unclear. We hypothesized that in CHF, unilateral renal DNx would improve cardiac autonomic balance. New Zealand White rabbits (n= 14) were instrumented with ventricular pacing leads to induce CHF and placed into one of four groups: non‐pace non‐DNx (Sham‐INV), non pace DNx (Sham‐DNx), pace non‐DNx (CHF‐INV) or pace DNx (CHF‐DNx). Two weeks following DNx (stripping the left renal artery of all visible fibers)/sham surgery, animals were paced at 380 BPM and CHF was confirmed by echocardiography. Heart rate (HR) and variability (HRV) were calculated from the ECG signal. CHF‐INV rabbits showed a significant decrease in HRV compared to Sham‐INV (p < .03) and this was attenuated in CHF‐DNx rabbits (7.2 ± 1.0 ms vs 13.6 ± 0.4 ms, p < .001). In CHF‐INV rabbits, bradycardia induced by IV metoprolol to assess sympathetic tone was exacerbated compared to sham (−24.0 ± 3.4 bpm vs −12.4 ± 2.4 bpm, p < .05) but was normalized in CHF‐DNx (−14.5 ± 1.4 bpm, p < .05), indicating a reduction in sympathetic tone by DNx. Conversely, the tachycardia in response to IV atropine as an assessment of vagal tone was not improved in CHFDNx vs CHF‐INV animals. These results suggest renal DNx improves cardiac autonomic balance in CHF by a reduction of cardiac sympathetic tone. Supported by PO1HL62222