Yanyan Claire Ji1, Ilija Uzelac2, Niels Otani3, Stefan Luther4, Robert F Gilmour5, Elizabeth M Cherry3, Flavio H Fenton2. 1. School of Physics, Georgia Institute of Technology, Atlanta, Georgia. Electronic address: yji47@gatech.edu. 2. School of Physics, Georgia Institute of Technology, Atlanta, Georgia. 3. School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York. 4. Max Planck Institute for Dynamics of Self-Organization, Gottingen, Germany. 5. University of Prince Edward Island, Charlottetown, Canada.
Abstract
BACKGROUND: Low-energy anti-fibrillation pacing (LEAP) has been suggested as an alternative treatment in symptomatic fibrillation patients. It significantly lowers the energy required compared with standard 1-shock defibrillation. OBJECTIVE: In this study, we investigated the mechanism of arrhythmia termination by LEAP and systematically analyzed the influence of shock period and timing on the success rate of LEAP. METHODS: We induced atrial and ventricular fibrillation in isolated canine hearts and applied LEAP and standard 1-shock defibrillation to terminate the arrhythmia. We simulated the arrhythmia and LEAP using a 2-dimensional bidomain human atrial model. RESULTS: The ex vivo experiments showed successful termination of atrial fibrillation and ventricular fibrillation using LEAP, with an average 88% and 81% energy reduction, respectively, and both experiments and simulations verified that synchronization from virtual electrodes is the key mechanism for termination of arrhythmia by LEAP using modified Kuramoto phase plots and fraction of tissue excited (FTE) plots. We also observed in simulations that LEAP is more effective when the shock period is close to the dominant period and the first shock is delivered when FTE is decreasing. CONCLUSIONS: Our results support synchronization as the mechanism for arrhythmia termination by LEAP, and its effectiveness can be improved by adjusting shock period and timing.
BACKGROUND: Low-energy anti-fibrillation pacing (LEAP) has been suggested as an alternative treatment in symptomatic fibrillation patients. It significantly lowers the energy required compared with standard 1-shock defibrillation. OBJECTIVE: In this study, we investigated the mechanism of arrhythmia termination by LEAP and systematically analyzed the influence of shock period and timing on the success rate of LEAP. METHODS: We induced atrial and ventricular fibrillation in isolated canine hearts and applied LEAP and standard 1-shock defibrillation to terminate the arrhythmia. We simulated the arrhythmia and LEAP using a 2-dimensional bidomain humanatrial model. RESULTS: The ex vivo experiments showed successful termination of atrial fibrillation and ventricular fibrillation using LEAP, with an average 88% and 81% energy reduction, respectively, and both experiments and simulations verified that synchronization from virtual electrodes is the key mechanism for termination of arrhythmia by LEAP using modified Kuramoto phase plots and fraction of tissue excited (FTE) plots. We also observed in simulations that LEAP is more effective when the shock period is close to the dominant period and the first shock is delivered when FTE is decreasing. CONCLUSIONS: Our results support synchronization as the mechanism for arrhythmia termination by LEAP, and its effectiveness can be improved by adjusting shock period and timing.
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Authors: Ilija Uzelac; Yanyan C Ji; Daniel Hornung; Johannes Schröder-Scheteling; Stefan Luther; Richard A Gray; Elizabeth M Cherry; Flavio H Fenton Journal: Front Physiol Date: 2017-10-20 Impact factor: 4.566