The research ran today in Circulation: Arrhythmia and Electrophysiology, a peer-reviewed journal of the American Heart Association. It presented leadless pacemakers like the Medtronic Micra as a safe and effective short-term option for children with slow heartbeats.
Children with slow heartbeats (bradycardia) already require pacemakers. However, active, growing children who receive standard pacemakers with leads (tiny wires) face higher risks for wire fractures and pacemaker complications. In these cases, the wires in typical pacemakers may break or malfunction, the researchers say.
Micra, which comes in at the size of a AAA battery, goes directly inside a patient’s heart without requiring leads. This study provides the first data on leadless pacemakers in a pediatric population in a real-world setting. It’s worth noting the major limitations of this study are the small study size and short-term follow-up.
“The leadless pacemaker works very well in children, just like it does in adults. We found it may be safely implanted in select pediatric patients that need pacing,” said lead study author Maully J. Shah, director of cardiac electrophysiology in the Cardiac Center at Children’s Hospital of Philadelphia and a professor of pediatrics at the Perelman School of Medicine at the University of Pennsylvania.
The researchers say the study demonstrates benefits of leadless pacing in children, potentially making them candidates for the technology.
“However, because of the current technology, which uses a very large catheter designed for adults to place the leadless pacemaker and lack of reliable future extractability of the pacemaker, the wider pediatric population is not able to benefit from this device.”
In a statement shared with MassDevice, Medtronic said it understands that pediatric patients have unique needs. The company is evaluating potential solutions to help serve them, including alternate delivery approaches. “At this stage, all pacemakers are considered off label for pediatric use and, as the smallest pacemaker in the world, the Micra pacemaker is obviously of great interest to physicians who are collaborating to help these patients.”
The data from the study pacemakers in the pediatric population
Researchers evaluated data in the registry for one brand of leadless pacemakers — the Medtronic Micra. They analyzed its performance in 63 children, ages 4 to 21 years (average age 15). For 77% of these children, this marked their first pacemaker.
In the analysis, the researchers saw successful implantation of a leadless pacemaker in 62 of 63 children. The heart’s electrical parameters remained stable in the first 24 hours in these successful patients.
Across an average follow-up period of about 10 months, the pacemaker demonstrated effectiveness in overall performance. This includes battery longevity, low pacing threshold and the ability to detect the heart’s native electrical beats. Shah said pacemaker batteries generally last between five and 10 years.
Potential complications to keep an eye on
In total, the researchers say 10 children (16%) experienced complications after receiving the leadless pacemaker. They reported most as due to minor bleeding, which they treated promptly and easily. The study saw three major complications including one blood clot in the femoral vein and one cardiac perforation. One patient had sub-optimal pacemaker function, requiring the removal of the pacemaker at one month. Two of the three complications occurred in patients weighing less than 60 pounds. Shah said the catheter-guided delivery systems, given their large size, may increase the risk of major complications.
The researchers say the pacemakers continued to show stable performance during follow-up, with no reported complications. They plan to follow patients for an additional five years. Shah calls leadless pacing “the wave of the future.”
“This is an excellent technology that may be offered to a wider pediatric population,” Shah said. “However, techniques and tools to place the device must be designed for smaller patients, specifically children, and there needs to be a mechanism to remove and replace this pacemaker without surgery when the battery runs out since pediatric patients will likely require pacing for the rest of their lives, which is several decades after implantation.”