Lower rate limit for pacing by cardiac resynchronization defibrillators: Should lower rate programming be reconsidered?

Heart Rhythm. 2021 Dec;18(12):2087-2093. doi: 10.1016/j.hrthm.2021.07.068. Epub 2021 Aug 8.

Abstract

Background: No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds).

Objective: The purpose of this study was to test the hypothesis that lower LRL programming is independently associated with survival, and that LRL and heart rate score (HrSc) are associated.

Methods: All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried. Baseline HrSc was defined as the percentage of all atrial sensed and paced beats in the tallest 10-beat histogram bin postimplant. LRL was assessed during repeated RPM uploads. Using a Cox model multivariable analysis, relationships between LRL, survival, HrSc, and other variables were evaluated. Survival was determined by query of death indices.

Results: Data analyzed included 61,881 subjects (mean follow-up 2.9 years). LRL ranged from 40 to 85 bpm. Baseline lower LRL was associated with younger age, less atrial fibrillation, female sex, and lower HrSc (P <.001 for all covariates). Lower LRL was associated with improved survival, with LRL 40 associated with the largest survival benefit. This was significant for all 3 HrSc subgroups (P <.001). An interaction between HrSc and LRL was observed, with the largest survival difference between HrSc groups observed at LRL-40 (P <.001).

Conclusion: LRL programming and HrSc were associated, and lower values of both were associated with improved survival in a large database of CRT-D subjects. Relationships between survival, LRL programming, and HrSc merit further study.

Keywords: Cardiac resynchronization; Heart rate score; Lower rate limit; Pacing; Risk factors; Survival.

MeSH terms

  • Aged
  • Atrial Fibrillation* / diagnosis
  • Atrial Fibrillation* / etiology
  • Atrial Fibrillation* / prevention & control
  • Cardiac Resynchronization Therapy Devices / standards
  • Cardiac Resynchronization Therapy Devices / statistics & numerical data
  • Cardiac Resynchronization Therapy* / adverse effects
  • Cardiac Resynchronization Therapy* / methods
  • Defibrillators / standards
  • Electrocardiography, Ambulatory / methods
  • Female
  • Heart Atria / physiopathology*
  • Heart Rate*
  • Humans
  • Male
  • Quality Improvement
  • Remote Sensing Technology
  • Risk Adjustment / methods*
  • Risk Factors
  • Survival Analysis
  • Treatment Outcome