Extravascular implantable cardioverter and leadless pacemaker interactions.

Area of Science:

• Cardiovascular medicine
• Biomedical engineering
• Medical device technology

Background:

• Traditional cardiac pacing and defibrillation devices use leads, risking complications like vascular damage and infection.
• Leadless pacemakers and extravascular implantable cardioverter-defibrillators (ICDs) offer leadless alternatives, combining components into single units or positioning electrodes outside the vasculature.
• Combined use of leadless pacemakers and extravascular ICDs is promising but lacks regulatory approval and exploration of device interactions.

Purpose of the Study:

• To evaluate the interactions between leadless pacemakers and extravascular ICDs during simultaneous operation.
• To assess the safety and potential risks associated with combining these advanced cardiac devices.

Main Methods:

• In-silico simulations, saline-tank experiments, and Monte Carlo simulations were employed.
• Focus was placed on evaluating ventricular fibrillation (VF) detection accuracy under various pacing conditions.
• Key parameters investigated included pacing pulse width, amplitude, device proximity, and orientation.

Main Results:

• Ventricular fibrillation detection remained unaffected by pacing pulse widths up to 0.24 ms and a pacing pulse-to-VF amplitude ratio of 2.
• Pacing pulses up to 3 V and 0.24 ms minimally impacted VF detection.
• Monte Carlo simulations predicted a 0-4% probability of undesired interactions in clinically relevant scenarios, with proximity affecting sensed amplitude but not orientation.

Conclusions:

• Extravascular ICDs and leadless pacemakers demonstrate potential for safe coexistence.
• A low risk of ventricular fibrillation undersensing was observed in simulated and experimental conditions.
• Further clinical investigations are warranted to validate these findings in patient populations.