Researchers at Texas Heart Institute (THI) and UCLA have just achieved a major milestone in the development of wirelessly powered, leadless pacemakers.
Their research, which has been recently published in the Nature Research journal Scientific Reports, the joint team explained how they used their innovative pacing system to provide synchronized biventricular pacing – where a pacemaker keeps the right and left ventricles of the heart pumping together using electrical impulses – to a human-sized heart in a preclinical research model.
The team’s announcement comes just months after THI was awarded a prestigious grant to the tune of $2.39 million in November 2019 to develop its wireless and leadless pacemakers.
The Problems with Current Cardiac Resynchronization Therapy (CRT)
Led by Dr Mehdi Razavi, Director of Electrophysiology Clinical Research & Innovations at THI and Associate Professor at Baylor College of Medicine and Professor Aydin Babakhani, Director of UCLA’s Integrated Sensors Laboratory, the research explores new areas of technology that could lead to new therapeutic treatment options for doctors who are treating patients with cardiovascular conditions such as heart failure and arrhythmias.
Around three in 10 patients with chronic heart failure also have an electrical conduction problem that requires a specific type of therapy to resynchronize the heart’s conduction system in its left and right ventricles, the heart’s two largest chambers. This therapy is delivered using long wires (leads) that are attached to the pacemaker to pace both of these chambers and, at present, this traditional lead-using pacemaker is the only available option.
Unfortunately, these leads are prone to fracturing and dislodging. This can lead to complications, and roughly one-third of patients do not respond well to the therapy.
Several members of the Texas Heart Institute research team intend to continue developing leadless and wirelessly powered pacemakers. Image Credit: Texas Heart Institute.
THI and UCLA’s New Leadless, Wirelessly Powered Pacemaker
By facilitating simultaneous pacing from multiple sites in the heart, THI and UCLA’s new wirelessly powered and leadless pacemaker system is designed to reduce these complications and provide safer options for biventricular pacing.
Its potential clinical benefits were, as the researchers put it, “impressive” and verified through measurements of electrical activity with an EKG and blood flow in the heart during testing. In particular, the team’s biventricular pacing strategy improved clinical outcomes when compared to single-chamber pacing. The research team believe that these preclinical testing results advance the possibility of using wirelessly powered, multisite pacing to address cardiac resynchronization challenges.
The team is presently working on miniaturizing the pacemaker to make it implantable in one or more pacing sites on the heart in a minimally invasive way, thus negating the need for intravascular leads and allow for synchronized pacing across multiple chambers.
The Texas Heart Institute and UCLA research team utilised an innovative pacing system to enable synchronized biventricular pacing to a heart in a preclinical research model. Image Credit: Texas Heart Institute.
Maintaining Wireless Power Transfer Efficiency
One of the team’s biggest challenges was maintaining wireless power transfer efficiency as the device is miniaturized and the antenna becomes less efficient.
To address this, 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 with the input circuitry of the pacing chips. The device has been miniaturized to such an extent that the entire pacemaker can fit inside a vein, with power provided through electromagnetic waves from an external controller, eliminating the need for onboard batteries.
The pacing device was inspired by silicon-based integrated microchips that were built in the UCLA laboratory.
"Miniaturized implantable medical devices are already on the market today. They are used in neural implants, in microchips that can be wirelessly programmed to deliver doses of osteoporosis drugs, and in disposable video capsules that can be swallowed to wirelessly transmit images of the GI tract while traveling through the body. So why not miniaturize the pacemaker?" stated Dr. Razavi.
The team’s ultimate goal? To develop a pacing system that can carry out real-time diagnoses of patients’ pacing needs, provide critical feedback to care teams, and deliver treatments itself.