Image: An exploded view of the epicardial micropacemaker system (Photo courtesy of CHLA).
A new study suggests that implanting a micropacemaker system in the pericardial sac surrounding the heart may expand pacing options for both children and adults.
Under development at the Children's Hospital of Los Angeles (CHLA; CA, USA) and the University of Southern California (USC; Los Angeles, USA), the percutaneous pacemaker includes an iridium corkscrew electrode that is implanted perpendicularly into the heart surface and a flexible, short, lead that acts as a spring-loaded hinge connecting the electrode to the pacemaker body. After deployment, the hinge returns to a 90-degree angle, aiding the micropacemaker to orient itself, thus minimizing system stress.
The micropacemaker includes an epoxy-encapsulated, relaxation-oscillator circuit that generates fixed-rate pulses, a lithium ion cell, and an inductive coil that captures energy from an extracorporeal radiofrequency (RF) electromagnetic field. A sheath with extended wire loops secures initial positioning, with subsequent formation of a biologic support matrix resulting from the natural fibrosis process. For the study, micropacemaker implantations were performed percutaneously in six pigs, using subxyphoid access to enter the pericardial space.
The researchers successfully placed an entire nonfunctional pacing system into the pericardial space in two of the first five animals, and successful implantation and capture was achieved using a functional system in the last animal. All animals studied during follow-up survived without symptoms in the initial postoperative period. According to the researchers, a major benefit of the new micropacemaker is that it enables pacing of the left ventricle (LV), while most systems only pace the right ventricle. The study was published on June 26, 2018, in Circulation: Arrhythmia and Electrophysiology.
“Much about this device and its implantation is novel, starting with implanting an entire pacing system in the pericardial space in a minimally invasive fashion, which has never been done before,” said lead author CHLA cardiologist Professor Yaniv Bar-Cohen, MD, director of the Southern California Consortium For Technology and Innovation in Pediatrics. “The micropacemaker has the potential to benefit a much larger population, including children, people born with congenital heart disease, and adults for whom traditional pacemakers are less than ideal.”
Children's Hospital of Los Angeles
University of Southern California