Abstract 2904: Finite Element Modeling of Subcutaneous ICD Predicts Alternative Optimized Lead Configurations
Introduction: Optimal electrode configurations for subcutaneous implantable defibrillators (S-ICD) are unknown. We used finite element models (FEM) to predict the myocardial electric field during defibrillation shocks (pseudo-DFT) associated with variations of electrode placement.
Methods: An image-based FEM was used to predict pseudo-DFTs across a range of technically feasible S-ICD electrode placements (Figure⇓). Generator location, lead location, length, geometry and orientation, and spatial relation of electrodes to ventricular mass were systematically varied. Factors contributing to low pseudo-DFTs were identified using general linear models.
Results: 122 single-electrode/array configurations and 28 dual-electrode configurations were simulated. Pseudo-DFTs for single-electrode orientations ranged from 0.60 –16.0 (mean 2.65±2.48) times that predicted for the base case, an anterior-posterior configuration that has been clinically validated. 32/150 configurations (21%) had pseudo-DFT ratios ≤1, indicating the existence of multiple novel and efficient configurations. Alignment of shock vector with ventricular myocardium and increased lead length were the most important factors correlated with pseudo-DFT, accounting for 70% of the predicted variation (R2=0.70, each factor p <0.05) in a combined general linear model.
Conclusions: FEM predicts that current electrode configurations proposed for S-ICD may not optimize shock efficiency, and that configurations maximizing shock vector alignment with myocardium and use of longer leads are likely to result in lower DFTs.