In Vivo Intravascular Pacing Using a Wireless Microscale Stimulator.

Millions of patients worldwide are implanted with permanent pacemakers for the treatment of cardiac arrhythmias and conduction disorders. The increased use of these devices has established a growing clinical need to mitigate associated complications. Pacemaker leads, in particular, present the primary risks in most implants. While wireless power transfer holds great promise in eliminating implantable device leads, anatomical constraints limit efficient wireless transmission over the necessary operational range. We thereby developed a transmitter-centered control system for wireless power transfer with sufficient power for continuous cardiac pacing. Device safety was validated using a computational model of the system within an MRI-based anatomical model. The pacer was then fabricated to meet the acute constraints of the anterior cardiac vein (ACV) to enable intravascular deployment while maintaining power efficiency. Our computational model revealed the wireless system to operate at > 50 times below the tissue energy absorption safety criteria. We further demonstrated the capacity for ex vivo pacing of pig hearts at 60 beats per minute (BPM) and in vivo pacing at 120 BPM following pacer deployment in the ACV. This work thus established the capacity for wireless intravascular pacing with the potential to eliminate complications associated with current lead-based deep tissue implants.