Among patients with heart failure with preserved ejection fraction (HFpEF) and a pacemaker, treatment with a moderately accelerated, personalised pacing rate resulted in an improved quality of life, N-terminal pro–brain natriuretic peptide (NT-proBNP) levels, and atrial fibrillation (AF) compared to the nominal setting of 60 beats per minute.
This was the headline finding reported by researchers in the myPACE randomised clinical trial, published online in JAMA Cardiology this week, in which they suggest that tailoring the pacemaker backup rate to approximate an individual’s resting heart rate may be a therapeutic target in patients with HFpEF.
Through the trial, Margaret Infeld (University of Vermont Larner College of Medicine, Burlington, USA) and colleagues tested the effects of the moderately accelerated personalised backup heart rate compared with usual care in patients with pre-existing pacemaker systems that limit pacemaker-mediated dyssynchrony. The trial enrolled patients with stage B and C HFpEF from the University of Vermont Medical Center pacemaker clinic between June 2019 and November 2020.
In total, 107 patients took part in the trial and were randomly assigned to personalised accelerated pacing or usual care, followed up for one year—50 patients assigned to the personalised accelerated pacing group and 57 to usual care. The personalised accelerated pacing heart rate was calculated using a resting heart rate algorithm based on height and modified by ejection fraction.
Investigators looked at a primary outcome of the serial change in Minnesota Living with Heart Failure Questionnaire (MLHFQ) score, and secondary endpoints including changes in NT-proBNP levels, pacemaker-detected physical activity, AF from baseline, and adverse clinical events.
Reporting the trial’s results in JAMA Cardiology, Infeld and colleagues write that over one-year follow-up, the median pacemaker-detected heart rate was 75 beats per minute in the personalised accelerated pacing arm and 65 beats per minute in usual care.
MLHFQ scores improved in the personalised accelerated pacing group (15 at one month, 9 at one year, p<0.001) and worsened with usual care (23 at one month, 27 at one year, p=0.03).
Additionally, personalised accelerated pacing led to improved changes in NT-proBNP levels, registering a mean decrease of 109pg/dL versus an increase of 128pg/dL with usual care (p=0.02) and device-detected AF, with a 27% relative risk reduction compared with usual care (p=0.04) over one year of follow-up.
Discussing the results of the trial in their JAMA Cardiology paper, Infeld and colleagues offer several potential mechanisms of action that may be behind the findings. “Although several potential mechanisms may explain the continued improvements in the personalised accelerated pacing group, cardiac remodelling likely plays a role,” they write.
In their conclusion, the researchers write that treatment with a moderately accelerated personalised backup pacing rate resulted in “significant” improvements in health-related quality of life compared with the standard lower rate setting of 60 beats per minute.
“Pacing at a moderately accelerated personalised backup rate in this population also improved natriuretic peptide levels, activity levels, and AF compared with usual care,” they go on to state. “The myPACE study supports the concept of heart rate modulation as a therapeutic intervention in HFpEF and provides additional evidence that moderately higher, and not lower, heart rates are beneficial in this complex patient population with an unmet need for therapies addressing underlying hemodynamic and cardiac structural abnormalities.”
Additional trials in larger populations of symptomatic patients with HFpEF are needed to confirm these findings, Infeld et al note.