Optimal method to achieve consistently low defibrillation energy requirements

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Reducing defibrillation energy requirements for implantable cardioverter-defibrillators (ICDs) is crucial for device miniaturization and extended longevity.
• High defibrillation thresholds (DFTs) can necessitate larger devices or additional electrodes, impacting patient outcomes.
• The TRIAD lead system (RV- --> SVC+ + CAN+) is used in ICD implantation.

Purpose of the Study:

• To prospectively evaluate the efficacy of repositioning the distal endocardial lead coil to achieve confirmed defibrillation thresholds (DFTs) of ≤15 J in patients requiring ICD implantation.
• To determine if lead repositioning can reduce DFTs in patients with initial thresholds exceeding 15 J.
• To assess the impact of lead repositioning on the overall energy requirements for defibrillation.

Main Methods:

• A prospective study involving 190 consecutive patients undergoing ICD implantation for ventricular fibrillation and/or recurrent ventricular tachycardia.
• Initial DFTs were measured with an endocardial dual-coil lead system. For patients with DFTs >15 J, the distal coil was repositioned towards the intraventricular septum.
• Ventricular fibrillation was induced, and successful defibrillation was confirmed at the lowest energy level (DFTplus).

Main Results:

• 177 out of 190 patients (93%) achieved successful defibrillation with ≤15 J using the initial lead position.
• In 13 patients (7%) with initial DFTs >15 J, repositioning the endocardial lead was necessary and successful in all cases, achieving ≤15 J.
• The mean DFTplus for all patients was 7.6 ± 3.7 J, with 87% achieving DFTplus ≤10 J. Repositioning resulted in a mean DFTplus of 11.0 ± 4.5 J in the repositioned group.
• No additional subcutaneous or epicardial electrodes were required for any patient.

Conclusions:

• Repositioning the endocardial lead coil in the right ventricle is a simple and effective method for reducing intraoperative high DFTs.
• This technique allows for the use of ICDs with a 20 J output in the vast majority of patients (87%), potentially reducing device size and increasing longevity.
• The study successfully avoided the need for additional electrodes, simplifying the implantation procedure and improving patient management.