Chronic open-loop ART via left- or right-side VNS is feasible and well tolerated in HFrEF patients. Safety and efficacy measures are encouraging and warrant further study.
Chronic open-loop ART via left- or right-sided VNS continued to be feasible and well-tolerated in patients with HF with reduced EF. Improvements in cardiac function and HF symptoms seen after 6 months of ART were maintained at 12 months.
ANTHEM-HF should provide additional and valuable information regarding the safety and the relationship between the site and intensity of ART and its salutary effects on HF.
Chronic ART in patients with symptomatic heart failure improves cardiac electrical stability, as reflected by reduced TWA levels and heart rate, suppresses VT, and increases baroreceptor sensitivity. These observations deserve study in a larger population.
Acute Heart Rate Dynamics During VNS. Background: Chronic vagus nerve stimulation (VNS) applied to produce biomimetic levels of parasympathetic activation is feasible, well tolerated, safe, improves left ventricular ejection fraction, NYHA class, heart rate variability, and baroreflex function, and reduces T-wave alternans (TWA) in patients with chronic heart failure. However, the acute effects of VNS on beat-to-beat heart rate dynamics have not been systematically characterized in humans.
Methods and Results:We evaluated acute effects of VNS on R-R-interval dynamics during the VNS titration period in patients (n = 59) enrolled in ANTHEM-HF trial by quantifying effects during continuous cyclic VNS (14-seconds on-time, 66-seconds off-time) adjusted to the maximum tolerable dose without excessive (<4 bpm) bradycardia during the 10-week titration period. VNS elicited an immediate change in heart rate that was correlated to VNS current amplitude, pulse width, and frequency. Heart rate decreased more in the 28 patients with right-sided stimulation (-2.22 ± 0.13 bpm) than in the 31 patients with leftsided stimulation (-0.60 ± 0.08 bpm, P < 0.001). The linear correlation between stimulus intensity and lengthening of the R-R interval was stronger among the 28 patients with right-sided VNS implantation (r = 0.88, P < 0.0001) than among the 31 patients with left-sided VNS implantation (r = 0.49, P < 0.002). In all patients, the heart rate change elicited by VNS was significantly greater than the change during the same timing intervals in 10 randomly selected patients without stimulation (+0.08 ± 0.06 bpm, P < 0.001).Conclusion: Instantaneous heart rate change during therapeutic levels of VNS in patients with heart failure indicates consistent modulation of the autonomic nervous system for both left-and right-sided
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