Abstract 13303: Influence of ARNI on Cardiac Autonomic Nervous System

Abstract

Background Mortality in heart failure with reduced ejection fraction (HFrEF) is associated with imbalance of cardiac autonomic nervous system (CANS). Sacubitril/ Valsartan (ARNI) reduces risk of death and HFrEF hospitalization. Whether ARNI exerts effects on CANS has not been studied. Accordingly, we prospectively compared heart rate variability (HRV) as a noninvasive measure of CANS before and after initiation of ARNI therapy. Methods: The study was as a single-arm prospective interventional study. Patients with HFrEF underwent echocardiography and standardized 30-minute 12-lead Holter ECG recording before and 3 months after initiation of ARNI therapy. Study endpoints were changes in HRV parameters (standard deviation of normal-to-normal intervals (SDNN), mean square of differences between consecutive R-R intervals (RMSSD), periodic repolarization dynamics (PRD) and deceleration capacity (DC) as well as left ventricular ejection fraction (LVEF) and heart rate (HR). Results: Between June 2021 and March 2022 we recruited 63 consecutive patients. At follow-up 48 (76.2%) patients were still on ARNI and therefore analyzed. Mean age was 65±13 years, 88% were male. All patients received identical beta-blockers dosage at baseline and follow-up. Heart rate was reduced by ~12% (P=0.005). SDNN increased by ~42% (P<0.001), RMSSD by ~55% (P<0.001) and ~DC by 370% (P<0.001). No change in PRD was observed (P=0.13). These results were accompanied by increased LVEF (28±6% vs. 38±10%, P<0.001) and reduced plasma nt-proBNP levels (5083±790 pg/ml vs. 1838±621 pg/ml, P=0.002). NYHA class improved from III to II. Conclusion Significant increase of parasympathetic CANS tone was observed after initiation of ARNI therapy as evidenced by decreased HR, increased DC, SDNN and RMSSD. Part of the beneficial effects of ARNI might be related to the accentuation of parasympathetic CANS modulating mortality risk and risk for HFrEF hospitalizations.