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Determinants of nonthoracotomy biphasic defibrillation
R P Horton1, R C Canby, C A Román
1Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA.
Pacing and Clinical Electrophysiology : PACE
|January 1, 1997
Summary
Body surface area (BSA) modestly influences defibrillation threshold (DFT) in biphasic implantable cardioverter-defibrillator (ICD) systems. Other factors like LVEF do not significantly predict DFT in patients undergoing testing.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Devices
Background:
- Defibrillation threshold (DFT) is crucial for implantable cardioverter-defibrillator (ICD) efficacy.
- Factors influencing DFT, particularly with biphasic waveforms, require further elucidation.
Purpose of the Study:
- To identify clinical variables correlating with DFT in patients receiving biphasic ICDs.
- To analyze the impact of patient characteristics on DFT outcomes.
Main Methods:
- Retrospective analysis of 128 patients from the Ventak P2/Endotak protocol with formal DFT testing.
- Regression analysis was used to assess the relationship between DFT and variables including age, BSA, LVEF, gender, lead configuration, and cardiac conditions.
Main Results:
- Body surface area (BSA) was a significant univariate predictor of DFT (P < 0.01, r = 0.3), explaining 9% of the variation.
- Mean DFT was 11 ± 5 J (range, 1-25 J).
- Left ventricular ejection fraction (LVEF) and other analyzed factors did not predict DFT.
Conclusions:
- BSA has a modest influence on DFT in biphasic ICD systems.
- Clinical factors beyond BSA, such as LVEF, do not appear to be reliable predictors of DFT in this patient cohort.