Study: Miniature pacemakers for neonates, infants perform reliably for two years

Editor's Note

Miniaturized pacemakers implanted in neonates and infants have demonstrated reliable performance for up to two years, with no unexpected device failures, according to a March 11 article in Healio. The research, published in Circulation: Arrhythmia and Electrophysiology, suggests that these modified pacemakers could offer a viable alternative for the smallest patients, addressing a critical gap in pediatric cardiac care.

As detailed in the article, traditional pacemakers are too large for neonates, leading to complications such as infection, erosion, and migration in up to 25% of cases. To mitigate these risks, researchers collaborated with Medtronic to develop a smaller device based on the Micra VR pacemaker. The modified version incorporates a polyetheretherketone (PEEK) polymer header and connects to a standard bipolar epicardial lead, making it roughly one-fifth the size of conventional models.  

The study evaluated outcomes in 29 infants, ranging from newborns to three-year-olds, who received the device between March 2022 and February 2024 at 12 US centers. Most of the patients were premature, with a median weight of 2.3 kg. The primary reason for implantation was congenital atrioventricular block, though other indications included postoperative heart block and sinus node dysfunction. On average, the pacemakers remained implanted for 325 days, and performance metrics—including battery longevity and pacing thresholds—remained consistent with projections.

Seven of the pacemakers were removed during the study, mostly for planned upgrades to standard devices as the children grew. Other explants occurred due to high capture thresholds, lead placement issues, or infection. Notably, none of the devices failed unexpectedly, and there were no replacements with the pediatric model. Two patients died during the study period, but their deaths were determined to be unrelated to the pacemaker or implantation procedure.

The article details a few procedural complications, including one case of skin erosion requiring revision, a late pericardial effusion, and a recurrent wound infection potentially linked to prior surgery. Despite these challenges, researchers view the study as a success.