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Does an SVC electrode further reduce DFT in a hot-can ICD system?
G A Mouchawar1, W K Wolsleger, P D Doan
1Pacesetter, Inc., Sylmar, California 91392-9221, USA.
Pacing and Clinical Electrophysiology : PACE
|January 1, 1997
Summary
Adding a superior vena cava (SVC) electrode to implantable cardioverter-defibrillators (ICDs) did not significantly reduce defibrillation thresholds (DFT) in pigs. This suggests the SVC electrode offers no apparent benefit for defibrillation efficacy in ICDs.
Area of Science:
- Cardiovascular Electrophysiology
- Medical Device Engineering
Background:
- Pectorally implanted ICDs using RV electrodes and housing for defibrillation are clinically accepted.
- The benefit of adding an SVC electrode to reduce defibrillation thresholds (DFT) remains debated.
Purpose of the Study:
- To evaluate whether incorporating an SVC electrode improves defibrillation efficacy compared to RV-only configurations.
Main Methods:
- Eight pigs were used to measure DFTs using a step-down protocol starting at 650 V.
- Two lead configurations were tested: Lead I (RV-->CAN) and Lead II (RV-->CAN and SVC).
- A biphasic waveform was delivered, and lead impedance was measured.
Main Results:
- No significant difference in DFT or E50 (50% success shock strength) was observed between RV-->CAN and RV-->CAN and SVC configurations for both Lead I and Lead II.
- Lead I demonstrated equivalent DFT performance to Lead II.
- A decrease in lead impedance was noted with the addition of the SVC electrode, but without a corresponding defibrillation benefit.
Conclusions:
- The addition of an SVC electrode to pectoral ICDs does not appear to offer a significant advantage in reducing defibrillation thresholds.
- Both tested lead configurations, including the one with an SVC electrode, provided comparable defibrillation performance.