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

Area of Science:

• Cardiology
• Biomedical Engineering
• Clinical Research

Background:

• Large-scale real-world data linking lower rate limit (LRL) programming and survival in cardiac resynchronization therapy-defibrillator (CRT-D) patients is lacking.
• Understanding factors influencing CRT-D patient outcomes is crucial for optimizing device therapy.

Purpose of the Study:

• To test the hypothesis that lower LRL programming is independently associated with improved survival in CRT-D patients.
• To investigate the association between LRL and heart rate score (HrSc) in this population.

Main Methods:

• Analysis of a large database (ALTITUDE) of dual-chamber CRT-D devices implanted between 2006-2011.
• Definition of baseline heart rate score (HrSc) based on the tallest 10-beat histogram bin.
• Assessment of LRL during remote patient monitoring (RPM) uploads.
• Multivariable Cox proportional hazards modeling to evaluate associations between LRL, survival, HrSc, and other variables.

Main Results:

• The study included 61,881 subjects with a mean follow-up of 2.9 years.
• Lower LRL programming was independently associated with younger age, less atrial fibrillation, female sex, and lower HrSc.
• Lower LRL was significantly associated with improved survival, with LRL of 40 bpm showing the greatest survival benefit across all HrSc subgroups.
• A significant interaction was observed between HrSc and LRL, with the most pronounced survival differences noted at LRL of 40 bpm.

Conclusions:

• Lower LRL programming and lower HrSc are associated and both linked to improved survival in a large cohort of CRT-D patients.
• The observed relationships between survival, LRL programming, and HrSc warrant further investigation to refine therapeutic strategies.