Approximately 30% of patients with chronic heart failure also have electrical conduction problems in their heart that require a type of therapy to resynchronize the heart’s conduction system in its two largest chambers. In these cases, doctors prescribe cardiac resynchronization therapy (CRT), which is delivered by long wires, called leads, attached to pacemakers to pace both of the bottom chambers of the heart.
When a patient needs both chambers of the heart synchronized, called biventricular pacing, a traditional pacemaker with leads is currently the only commercially available option. Unfortunately, these leads are prone to fracturing, dislodging, and migrating away from the original location.
Researchers have developed a wirelessly powered, leadless pacemaker and used it to provide synchronized biventricular pacing to a human-sized heart in a preclinical research model. By allowing simultaneous pacing from multiple sites in the heart, the leadless, wirelessly powered pacemaker system aims to reduce the complications associated with the traditional pacemakers in use today and opens the door for safer and more effective biventricular pacing options.
Previous research by the team proved the system’s ability to wirelessly power a single site in the hearts of small, medium, and large open-chest research models. In the new study, the tiny pacemakers — only a fraction of the size of a quarter — were shown to work in a closed-chest porcine model via wireless powered transfer to custom-designed, low-power integrated circuits on the heart.
The biventricular pacing strategy improved important clinical outcome measures when compared to single-chamber pacing. Overall, the results advance the possibility of using wirelessly powered, multisite pacing to address cardiac resynchronization challenges. The team is currently working on further miniaturizing the pacemaker to make it implantable at one or more desired pacing sites on the heart in a minimally invasive manner. This will eliminate the need for intravascular leads and, most importantly, allow for synchronized and leadless pacing across multiple chambers of the heart, which offers the ability to provide patient-specific CRT.
A significant challenge of this technology is maintaining the efficiency of wireless power transfer as the device becomes very small and the antenna becomes less efficient. The team significantly lowered the power consumption of the electronics used in the pacemaker, integrating all the elements on a single chip and designing antennas that resonate strongly with the input circuitry of the pacing chips.
The ultimate goal is to build a pacing system that can diagnose the pacing needs of the heart in real time, provide critical feedback to the care team if needed, and deliver tailored treatments. Thus, the pacemaker will eventually be able to harness the power of artificial intelligence (AI) by learning from the data it generates to identify patterns and make adjustments. This capability could ensure constant, optimal, patient-specific therapy.