Porcine Cardiac Arrest Model Using an Implantable Defibrillator.

This study presents a reproducible porcine cardiac arrest model utilizing an implantable cardioverter-defibrillator (ICD) for reliable induction and cardioversion of ventricular fibrillation (VF), as well as intracardiac ECG monitoring during resuscitation. Large animal models are vital for translational research in cardiac arrest; however, conventional VF induction and cardioversion techniques -- primarily using external electrodes and defibrillation -- are often hampered by motion artifacts, inconsistent conversion rates, and high animal resource use. This protocol describes repeated cycles of VF induction and cardioversion within the same animal, providing precise control while minimizing physiological stress and animal numbers, in accordance with the 3R principles (Replacement, Reduction, and Refinement). The ICD-based method allows for accurate rhythm monitoring by intracardiac ECG throughout resuscitation, with improved artifact resistance compared to surface ECG. Eleven pigs underwent repeated VF induction and cardioversion, with high success rates and recovery of spontaneous circulation. The model enables standardized and reliable data acquisition for cardiac arrest studies, ensuring experimental consistency and facilitating reproducible investigation of pathophysiology and resuscitation strategies while minimizing animal use.