How the study worked
The single-center trial entered 107 participants with HFpEF and pacemakers set, at baseline, to a backup resting HR of 60 bpm; their age averaged 75 and 48% were women. Only patients with devices for atrial pacing, conduction-system pacing, or biventricular pacing – which are unlikely to promote ventricular dyssynchrony – were included.
They were randomly assigned, double-blind, to have their devices set to an accelerated backup rate or to be continued at 60 bpm. The backup resting rate set for the intervention group’s 50 patients was individualized based on height and other factors; the median was 75 bpm.
Scores on the Minnesota Living with Heart Failure Questionnaire, the primary endpoint, improved in the intervention group, compared with baseline, by about 11 points after 1 month and by 15 points after 1 year (P < .001).
The scores in the usual-care group deteriorated by half a point and by 3.5 points at 1 month and 1 year (P = .03), respectively.
Consistent advantages for the accelerated-HR strategy were evident throughout the major secondary endpoints. For example, levels of N-terminal pro-B-type natriuretic peptide fell an average 109 pg/dL after 1 month in the accelerated-HR group and rose a mean of 128 pg/dL in the usual-care group (P = .02).
Mean daily pacemaker-monitored activity level rose by 47 minutes by 1 year in the accelerated-HR group, compared with a drop of 22 minutes for those assigned to the standard-care rate (P < .001).
AFib was detected in 18% of intervention patients at the 1-year follow-up, down from 31% at baseline. Their risk ratio for AFib at 1 year was 0.73 (95% confidence interval, 0.55-0.99, P = .04), compared with the control group.
In other patients with HFpEF “we have done pacing studies where we just ramped up the pacing rate, and we see that these pressures in the left atrium actually drop immediately,” Dr. Meyer said. It’s that “unburdening of the atria,” he added, that probably leads to the reduction in AFib.
Dr. Meyer reported holding a patent for pacemakers for HFpEF licensed to Medtronic. Dr. Zile said he consults for Medtronic and has no other relevant financial relationships.
A version of this article first appeared on Medscape.com.