Porcine Cardiac Arrest Model Using an Implantable Defibrillator
January 9th, 2026
This protocol demonstrates the use of an implantable cardioverter-defibrillator (ICD) to reliably induce ventricular arrhythmias, perform internal cardioversion, and obtain intracardiac ECG recordings in a porcine model.
We wanted to develop a simple, reliable model of ventricular fibrillation and cardioversion that gives more stable results and allows us to use fewer animals in resuscitation studies. We use an implantable cardioverter defibrillator to reliably induce ventricular fibrillation, perform cardioversion and intracardiac electrocardiogram. After preparing the pig, turn the deeply anesthetized animal into a supine position and fixate the limbs using a gauze bandage.
Disinfect the neck, jaw, groin and belly using chlorhexidine at a concentration of 5 milligrams per milliliter in ethanol, and cover the disinfected areas with sterile drapes. Stretch a hind leg to extend the iliac artery. Using ultrasound, locate the iliac artery and insert a 5 French pulse index continuous cardiac output arterial catheter using the Seldinger technique.
Connect the arterial catheter to a pre-filled pressure transducer and flush set. After zeroing the transducer, confirm a good arterial pressure tracing and then release the hind leg. Tilt the pig into the Trendelenburg position and increase the ventilator positive and expiratory pressure to 10 centimeters of water to distend the neck veins.
Under ultrasound guidance, locate the right external jugular vein and insert a seven French vascular introducer using the Seldinger technique. Confirm venous backflow and flush the introducer with saline. Next, insert a 9 French 2-lumen central venous access set with a hemostasis valve.
Confirm venous backflow through the lumens. Transfer the sedation and fluid infusions to the catheter. Then connect a pressure transducer to one of the catheter lumens and confirm a central venous pressure wave form.
Decrease ventilator positive and expiratory pressure to 5 centimeters of water. Insert a single coil implantable cardioverter defibrillator or ICD electrode through the vascular introducer and advance it to the right ventricular apex. Then connect the ICD lead to a pacing system analyzer using the dedicated connector.
Ensure that the intracardiac R-wave amplitude is greater than 6 millivolts. Use a scalpel to make the 4 centimeter horizontal skin incision below the left clavicle. Then use diathermy followed by blunt finger dissection to create a subcutaneous pocket large enough to accommodate the ICD.
Connect the lead to the ICD and place the device into the subcutaneous pocket. Confirm that the right ventricular lead remains in a stable position. Program the pacing mode to desired settings after connecting the ICD to the programmer and review the R-wave pacing threshold and impedances.
Then program the tachyarrhythmia therapy parameters. On the programmer screen, select the Test icon and open the Ventricular Fibber and NIPS folder. Under Ventricular Fibber, select the DC Fibber and set it to 7.5 volts for two seconds to induce ventricular fibrillation.
When ventricular fibrillation is induced, use automatic delivery to allow the device to deliver therapy according to programmed parameters. Induce ventricular tachycardia by selecting the Ventricular NIPS icon. Choose the Burst icon and set the desired cycle length, such as 240 milliseconds.
Then press Hold to apply burst for up to 20 seconds. If ventricular tachycardia or ventricular fibrillation is induced, deliver therapy according to the program settings in the Tachy folder. Select the Parameters icon to review settings and ensure restoration of sinus rhythm.
Monitor the arterial pressure via the iliac arterial catheter. Supplement this with continuous Doppler monitoring of blood flow by positioning the hands-free probe perpendicular to the left carotid artery. Verify that the Doppler display shows a clear carotid flow trace.
Next, secure the probe thoroughly with adhesive tape. Monitor the cardiac rhythm using the intracardiac electrocardiogram obtained from the pacemaker and the surface electrocardiogram displayed on the monitor. After inducing ventricular fibrillation or ventricular tachycardia, observe cessation of carotid flow on the Doppler trace and maintain the no flow period as per the study protocol.
Then begin manual cardiopulmonary resuscitation, mechanical compressions, or other interventions. Confirm the return of spontaneous circulation using the invasive arterial pressure and the non-invasive ultrasound guided flow velocity. When required, convert the pig to sinus rhythm by delivering a manual DC shock.
Terminate the ventricular fibrillation within 120 seconds to maximize the likelihood of successful conversion. If the animal is in ventricular tachycardia, use anti-tachycardia pacing or synchronized cardioversion. Finally, allow the animal to rest and ensure normalization of physiological parameters, including blood pressure, end-tidal carbon dioxide and pH.
The Ventricular Fibber mode induced ventricular fibrillation or ventricular tachycardia in all 11 animals. ICD delivered therapy subsequently restored sinus rhythm and spontaneous circulation in every animal. The average success rate for achieving return of spontaneous circulation after induced ventricular fibrillation was around 92%The ICD induced an average of 18 ventricular arrhythmias per animal, comprising ventricular fibrillation and ventricular tachycardia.
Compared to other methods, our approach achieved a 92%circulation restoration success with artifactory rhythm monitoring during cardiopulmonary resuscitation. The main challenge is the need for specialized equipment and skilled operators for ICD implantation and programming. Our model increases resuscitation success from approximately 50 to 90%enabling repeated ventricular fibrillation, CPR, cardioversion cycles per animal, and significantly reduces animal use.
Overview
This article describes a reproducible porcine cardiac arrest model that employs an implantable cardioverter-defibrillator (ICD) for the reliable induction and cardioversion of ventricular fibrillation (VF). The protocol enables repeated VF induction and cardioversion cycles within the same animal, allowing for precise control, improved monitoring, and reduced animal use in cardiac arrest research.
Key Study Components
Area of Science
- Cardiac arrest research
- Translational medicine
- Large animal models
Background
- Large animal models are essential for translational cardiac arrest studies.
- Traditional VF induction and cardioversion methods use external electrodes, which can introduce motion artifacts and inconsistent results.
- Conventional approaches often require high animal resource use.
- There is a need for more reliable, artifact-resistant, and resource-efficient models.
Purpose of Study
- To develop a reproducible porcine cardiac arrest model using an ICD for VF induction and cardioversion.
- To enable repeated VF cycles in the same animal, minimizing physiological stress and animal numbers.
- To improve rhythm monitoring accuracy during resuscitation.
Methods Used
- Implantation of an ICD in pigs.
- Induction and cardioversion of VF using the ICD.
- Intracardiac ECG monitoring throughout resuscitation.
- Repeated VF induction and cardioversion cycles within the same animal.
Main Results
- Eleven pigs underwent repeated VF induction and cardioversion with high success rates.
- Recovery of spontaneous circulation was consistently achieved.
- Intracardiac ECG provided accurate rhythm monitoring with improved artifact resistance compared to surface ECG.
- The model enabled standardized and reliable data acquisition for cardiac arrest studies.
Conclusions
- The ICD-based porcine model offers precise control over VF induction and cardioversion.
- It minimizes animal use and physiological stress, aligning with the 3R principles.
- This approach facilitates reproducible investigation of cardiac arrest pathophysiology and resuscitation strategies.
Frequently Asked Questions
Executive Industry Relevance
Reliable large animal models are critical for translational cardiac arrest research, enabling robust evaluation of resuscitation strategies and device interventions. The use of an implantable defibrillator in a porcine model provides precise control over ventricular fibrillation induction and cardioversion, supporting reproducibility and data integrity. This approach minimizes animal use and physiological stress, aligning with enterprise goals for ethical, scalable, and predictive preclinical research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables rigorous interrogation of cardiac arrest mechanisms in a physiologically relevant system.
- Supports functional validation of device-based interventions and resuscitation protocols.
- Facilitates predictive confidence in translational cardiac research pipelines.
Screening & Assay Development
- Provides a standardized platform for evaluating cardiac rhythm management devices and therapies.
- Delivers reproducible, quantitative intracardiac ECG outputs for assay development.
- Reduces variability and artifact interference compared to external electrode methods.
Translational & Preclinical Research
- Aligns with disease-relevant physiology for preclinical validation of cardiac arrest interventions.
- Enables continuity from discovery through preclinical assessment of device efficacy and safety.
- Supports risk-adjusted advancement of cardiac therapeutics and technologies.
Pipeline & Workflow Integration
This ICD-based porcine model bridges early discovery and preclinical validation, providing a robust workflow for cardiac arrest research and device evaluation.
- Discovery Biology: Supports hypothesis testing and mechanistic de-risking in cardiac arrest pathophysiology.
- Screening: Offers reproducible, artifact-resistant ECG data for reliable compound or device screening.
- Analytics: Enables quantitative assessment of resuscitation outcomes and rhythm conversion rates.
- Translational Research: Facilitates alignment with clinical endpoints and biomarker strategies in cardiac arrest studies.
- Enterprise Reuse: Establishes a scalable, standardized model for ongoing cardiac device and therapy evaluation.
Operational & Enterprise Impact
- Scientific Value: Enhances predictive confidence and target validation in cardiac arrest research.
- Operational Value: Improves standardization, reproducibility, and resource efficiency in large animal studies.
- Strategic Value: Supports informed go/no-go decisions and reduces late-stage biological risk.
- Portfolio Impact: Enables risk-adjusted prioritization of cardiac device and therapy candidates.
Implementation Considerations
- Requires expertise in large animal surgery and cardiac electrophysiology.
- Demands access to implantable defibrillator systems and intracardiac ECG monitoring infrastructure.
- Necessitates cross-team standardization for protocol reproducibility and data comparability.
- Adaptation may be needed for different animal models or device platforms.
- Practical limitations include surgical complexity and specialized equipment requirements.
Biopharma FAQs
Chapters in this video
0:00
Introduction
0:40
Arterial Catheter Placement
1:43
Placement of Vascular Introducer and Central Venous Catheter (CVC)
2:38
Implantable Cardioverter-Defibrillator Electrode Placement
3:45
Pacemaker/Defibrillator Programming
5:12
Establishing Non-Invasive Continuous Carotid Doppler Monitoring
5:40
Conducting Cardiac Arrest Studies
7:07
Results
7:51
Conclusion
