A multidisciplinary team within Norton Children’s Heart Institute, in Louisville, Kentucky, affiliated with the University of Louisville School of Medicine, worked together to save the life of an infant born with congenital structural heart defects and complete atrioventricular block (CCAVB) that led to a slow heart rate. The patient was too small for the traditional path of care, driving the team to perform the first known human implantation of a newly designed tiny pacemaker in a premature infant.
“It is remarkable how our team of pediatric specialists came together with the device company to offer a resolution for such a small patient weighing less than three pounds at the time of implant,” says Soham Dasgupta, M.D., pediatric electrophysiologist at Norton Children’s Heart Institute and assistant professor of pediatric cardiology. “This case is unlike any other and we are pleased to see this patient thriving.”
Approximately 1 in 22,000 infants are born with CCAVB. Untreated, the condition has a high incidence of prolonged illness or death. The usual treatment involves implantation of a pacemaker once the patient meets a minimum body size, typically 4 1/2 to 5 1/2 pounds, to accommodate the implantable device. Taking time for the baby to grow while being otherwise treated is strongly preferred for this situation. With this patient, however, the traditional plan was not working.
“In this instance, the patient was not of the optimal size and medical and conservative management was unsuccessful, so a specially modified pediatric-sized pacemaker, also known as an implantable pulse generator (IPG) was used,” Dasgupta says.
Dasgupta and his colleague, Christopher L. Johnsrude, M.D., director of pediatric and adult congenital electrophysiology and associate professor of pediatric cardiology, reviewed the relevant preclinical data from a procedure where a similar tiny pediatric IPG had been implanted in an adult Yucatan miniature pig, an animal with a heart that resembles a child’s heart.
Once it was determined the pediatric IPG was potentially compatible with the patient at Norton Children’s, Dasgupta worked with Norton Children’s Research Institute, affiliated with the University of Louisville School of Medicine, and the device manufacturer, to obtain local Institutional Review Board approval and emergency authorization from the U.S. Food and Drug Administration.
Once the device was in hand, the procedure to place the implant was completed over the course of a two-hour open-heart surgery. The device measures 1.16 by 0.65 by 0.38 inches and weighs 0.18 ounces.
“While the operative steps might be comparable to the usual pacemaker implantation surgery, this surgery was especially delicate due to the very small size of the baby,” says Bahaaldin Alsoufi, M.D., chief of pediatric cardiothoracic surgery, co-director of Norton Children’s Heart Institute and professor of cardiothoracic surgery. “This tiny pacemaker generator was positioned in the abdominal wall on the right side and was connected to the usual leads that were attached to the heart. This novel device will provide the necessary support that the baby needs. At time of repair of the patient’s congenital heart defect in the future, we will be able to utilize these same leads and likely connect them then to a traditional larger pacemaker generator.”
The patient responded well to the new device, growing almost four times his size before being safely discharged. “We demonstrated that this is doable,” says Dasgupta. “It a good option to have that we did not have before.”