Ampere Hour as a Predictor of Cardiac Resynchronization Defibrillator Pulse Generator Battery Longevity: A
Christopher R Ellis1, Deanna I Dickerman2, Jodi M Orton1
1Vanderbilt Heart and Vascular Institute, Vanderbilt University Medical Center, Nashville, Tennessee.
Insights
Cardiac resynchronization defibrillator (CRT-D) battery capacity, measured in Ampere hours (Ah), significantly predicts device longevity. Higher Ah ratings correlate with longer survival to elective replacement, reducing premature pulse generator replacements.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Device Technology
Background:
- Cardiac resynchronization defibrillator (CRT-D) devices enhance survival in specific heart failure patients.
- High CRT pacing rates can lead to premature battery depletion and pulse generator (PG) replacement.
- Ampere hour (Ah) is a metric for PG battery capacity and a potential indicator of CRT-D longevity.
Purpose of the Study:
- To evaluate the relationship between CRT-D battery capacity (Ah) and survival to elective replacement indicator (ERI).
- To determine if higher Ampere hour ratings in CRT-D devices predict longer device longevity.
- To analyze factors influencing premature pulse generator replacement in CRT-D systems.
Main Methods:
- A multicenter retrospective study of CRT-D devices implanted between August 1, 2008, and December 31, 2010.
- Analysis of device survival to ERI based on battery capacities of 1.0 Ah, 1.4 Ah, and 2.0 Ah.
- Statistical analysis including odds ratios to identify predictors of ERI.
Main Results:
- A total of 1,302 patients were followed for an average of 3.0 ± 1.3 years.
- ERI occurred in 13.5% of 1.0 Ah devices versus 3.8% for 1.4 Ah and 0.3% for 2.0 Ah devices.
- 1.0 Ah devices had a significantly higher odds ratio (9.73) of reaching ERI compared to 1.4 Ah or 2.0 Ah devices (P < 0.0001).
Conclusions:
- CRT-D battery capacity (Ah) is a strong predictor of survival to ERI.
- Higher Ampere hour ratings are associated with extended device longevity.
- Further research into the cost and morbidity of early PG replacement for 1.0 Ah systems is recommended.
Background:
Cardiac resynchronization defibrillator (CRT-D) devices improve survival for New York Heart Association classes II-IV systolic heart failure patients with QRS > 120 ms and left ventricular ejection fraction < 35%. A limitation of 100% CRT pacing is excess battery depletion and pulse generator (PG) replacement compared to VVI or dual-chamber systems. Ampere hour (Ah) measures PG battery capacity and may predict CRT-D device longevity.
Methods:
We performed a multicenter retrospective study of all CRT-D devices implanted at our centers from August 1, 2008 to December 31, 2010. Analysis was performed for survival to elective replacement indicator (ERI) between 1.0 Ah, 1.4 Ah, and 2.0 Ah devices, per manufacturers' specifications.
Results:
One thousand three hundred and two patients were studied through December 31, 2014. Patients were followed for an average of 3.0 ± 1.3 years (794 1.0 Ah, 322 2.0 Ah, and 186 1.4 Ah devices under study). CRT-D generator ERI occurred in 13.5% of 1.0 Ah systems (107 out of 794), versus 3.8% in 1.4 Ah (seven out of 186), and 0.3% in 2.0 Ah devices (one out of 322) over mean follow-up of 3.0 years. Odds ratio (OR) for reaching ERI with 1.0 Ah device versus 1.4 Ah or 2.0 Ah was 9.73, P < 0.0001. Univariate predictors for ERI included 1.0 Ah device and LV pacing output >3V @ 1 ms (OR: 3.74, P < 0.001). LV impedance >1,000 ohms predicted improved device survival (OR: 0.38, P = 0.0025).
Conclusions:
CRT-D battery capacity measured by Ah is a strong predictor of survival to ERI for modern systems. Further study on cost and morbidity associated with early PG change in 1.0 Ah systems is warranted.
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