OBJECTIVES The aim of this study is to investigate the influence of new subcutaneous Implantable Cardioverter Defibrillator (ICD) electrode placements on the Defibrillation Threshold (DFT), shock impedance, and sites of activation in the heart caused by a low voltage shock. BACKGROUND The subcutaneous ICD, though it has many advantages due to its less invasive nature compared to the transvenous ICD, requires higher energy shocks to terminate ventricular arrhythmias, and is not currently thought to be able to reliably pace the heart. METHODS A cohort of nine heart-torso computer models built from computed tomography scans are used to simulate the electric field that occurs during defibrillation. The conventional subcutaneous configuration is tested, along with new “dual sternal”, “L”, and “posterior” configurations, where an additional ground or shocking electrode is present. The estimated DFT (defined as the voltage required to produce an electric field of 5 volts/cm or more in at least 95 % of the ventricular myocardium) along with the shock impedance is computed for all electrode configurations. In addition, the number and location of stimulated sites in the heart is noted for each configuration after delivery of a low voltage shock, to assess respective potential pacing capabilities. RESULTS In average, the addition of an anterior shocking electrode in the “L” or “dual sternal” position leads to 1.5 times lower DFT and shock impedance than the ones obtained with the classical configuration. The small torso has 1.6 times lower DFT than the medium and large torso in average. Dilated and hypertrophic cardiomyopathies have little impact on the computed DFT. The different electrode configurations cause different number and location of simulated sites in the heart after delivery of a low voltage shock. CONCLUSIONS The models suggest that an S-ICD implantation involving the addition to the conventional configuration of a shocking anterior electrode in the “L” or “dual sternal” position enables to reduce the estimated DFT in all torso size. Pacing by the S-ICD seems feasible.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-223644 |
| Date | January 2018 |
| Creators | Plancke, Anne-Marie |
| Publisher | KTH, Skolan för kemi, bioteknologi och hälsa (CBH) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-CBH-GRU ; 2018:14 |
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