During cardiopulmonary bypass, 150 cardiac surgical patients were prospectively evaluated for the number, energy, current, and success rates of direct current (DC) shocks required to terminate reperfusion ventricular fibrillation (1 degree) or ventricular fibrillation occurring subsequent to a nonfibrillatory reperfusion rhythm (2 degrees). Thirty-one percent of 1-J shocks and 58% of 2.5-J shocks defibrillated. Above 2.5 J, the defibrillation success rate reached a plateau of 50-60%. Myocardial resistance decreased significantly after the first shock but remained stable during subsequent shocks. Lower defibrillating currents and myocardial resistances than had been previously reported were observed. The feasibility of low-energy defibrillation during cardiopulmonary bypass was therefore documented.
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http://dx.doi.org/10.1016/0735-6757(85)90030-0 | DOI Listing |
Chaos
November 2024
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
This study investigates ultra-low-energy defibrillation protocols using a simple two-dimensional model of cardiac tissue. We find that, rather counter-intuitively, a single, properly timed, biphasic pulse can be more effective in defibrillating the tissue than low energy antitachycardia pacing (LEAP), which employs a sequence of such pulses, succeeding where the latter approach fails. Furthermore, we show that, with the help of adjoint optimization, it is possible to reduce the energy required for defibrillation even further, making it three orders of magnitude lower than that required by LEAP.
View Article and Find Full Text PDFChaos
September 2024
Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, USA.
Cardiac arrythmias are a form of heart disease that contributes toward making heart disease a significant cause of death globally. Irregular rhythms associated with cardiac arrythmias are thought to arise due to singularities in the heart tissue that generate reentrant waves in the underlying excitable medium. A normal approach to removing such singularities is to apply a high voltage electric shock, which effectively resets the phase of the cardiac cells.
View Article and Find Full Text PDFResusc Plus
September 2024
Department of Prehospital Emergency Medical Sciences, Faculty of Health Sciences, Hiroshima International University, 555-36 Kurose-gakuendai, Higashi-hiroshima, Hiroshima 739-2695, Japan.
Aim: This study aimed to elucidate the risk of electric shock when the general public, not wearing Personal Protective Equipment (PPE), is in contact with a patient, and a defibrillation shock is inadvertently delivered.
Methods: A simulation study was conducted simulating the following scenarios. 1) Both the rescuer and the patient were isolated from the ground, with the rescuer making single-point contact with the patient.
Pacing Clin Electrophysiol
September 2024
Arrhytmia Unit, Cardiology Department, Hospital Miguel Servet, Zaragoza, Spain.
Front Netw Physiol
July 2024
Computational Physics for Life Science, Nuremberg Institute of Technology Georg Simon Ohm, Nuremberg, Germany.
Current treatments of cardiac arrhythmias like ventricular fibrillation involve the application of a high-energy electric shock, that induces significant electrical currents in the myocardium and therefore involves severe side effects like possible tissue damage and post-traumatic stress. Using numerical simulations on four different models of 2D excitable media, this study demonstrates that low energy pulses applied shortly after local minima in the mean value of the transmembrane potential provide high success rates. We evaluate the performance of this approach for ten initial conditions of each model, ten spatially different stimuli, and different shock amplitudes.
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