Generation of a cohort of whole-torso cardiac models for assessing the utility of a novel computed shock vector efficiency metric for ICD optimisation

• Published in: Computers in biology and medicine 2019-09, Vol.112, p.103368, Article 103368
• Main Authors: Plancke, Anne-Marie, Connolly, Adam, Gemmell, Philip M., Neic, Aurel, McSpadden, Luke C., Whitaker, John, O'Neill, Mark, Rinaldi, Christopher A., Rajani, Ronak, Niederer, Steven A., Plank, Gernot, Bishop, Martin J.
• Format: Article
• Language: English
• Subjects: Adult; Aged, 80 and over; Arrhythmias, Cardiac - diagnostic imaging; Arrhythmias, Cardiac - physiopathology; Arrhythmias, Cardiac - therapy; Cardiac arrhythmia; Cardiac arrhythmias; Cardiac electrophysiogy; Cardiac modelling; Cardiomyopathy; Complications; Computation; Computer applications; Computer Simulation; Conductivity; Configuration management; Configurations; CT imaging; Defibrillation; Defibrillators; Defibrillators, Implantable; Design optimization; Efficiency; Electrodes; Energy; Energy conversion efficiency; Female; Heart; Heterogeneity; Humans; Impedance; Implanted cardioverter defibrillators; Male; Mathematical models; Medical imaging; Middle Aged; Models, Cardiovascular; Patients; Shock; Simulation; Skin; Spinal cord; Tomography, X-Ray Computed; Torso; Ventricle
• ISSN: 0010-4825; 1879-0534; 1879-0534
• DOI: 10.1016/j.compbiomed.2019.103368

Implanted cardiac defibrillators (ICDs) seek to automatically detect and terminate potentially lethal ventricular arrhythmias by applying strong internal electric shocks across the heart. However, the optimisation of the specific electrode design and configurations represents an intensive area of research in the pursuit of reduced shock strengths and fewer device complications and risks. Computational whole-torso simulations play an important role in this endeavour, although knowing which specific metric should be used to assess configuration efficacy and assessing the impact of different patient anatomies and pathologies, and the corresponding effect this may have on different metrics has not been investigated. We constructed a cohort of CT-derived high-resolution whole torso-cardiac computational models, including variants of cardiomyopathies and patients with differing torso dimensions. Simulations of electric shock application between electrode configurations corresponding to transveneous (TV-ICD) and subcutaneous (S-ICD) ICDs were modelled and conventional metrics such as defibrillation threshold (DFT) and impedance computed. In addition, we computed a novel metric termed the shock vector efficiency (η), which quantifies the fraction of electrical energy dissipated in the heart relative to the rest of the torso. Across the cohort, S-ICD configurations showed higher DFTs and impedances than TV-ICDs, as expected, although little consistent difference was seen between healthy and cardiomyopathy variants. η was consistently