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Mikey Oliveri, now two months old, is thriving at home in East Meadow, New York, after receiving the world’s smallest pacemaker on December 17, 2024. Mikey, who was born prematurely and weighed just 2.5 kg (5.5 pounds), had his life saved by this tiny, specially adapted device to meet the needs of his unique condition, thanks to an expert team at Hassenfeld Children’s Hospital at ��ɫAV Langone.

His mother, Sarah Oliveri—already a mom to two boys—presented well until 20 weeks, when an exam with maternal–fetal medicine specialists at ��ɫAV Langone Hospital—Long Island indicated signs of heart block, a rare and dangerous heart condition called congenital complete heart block. This condition disrupts the heart’s electrical system, preventing the normal signal to pump blood from reaching the lower chambers and causing a slow or irregular heartbeat.

After the diagnosis was confirmed in August 2024 by Emina Hodzic, MD, a pediatric cardiologist at ��ɫAV Langone Ambulatory Care Garden City, Mikey’s heart was closely monitored by experts in the Fetal Heart Disease Program, part of the Pediatric Congenital Heart Program at Hassenfeld Children’s Hospital in Manhattan, in close collaboration with ��ɫAV Langone’s maternal–fetal medicine specialists.

When we first saw signs of congenital heart block, our team on Long Island worked seamlessly with specialists in Manhattan to make sure Sarah and her baby got the care they needed at every stage,” said Justin S. Brandt, MD, director of maternal–fetal medicine services. “It was a truly collaborative effort to ensure a smooth transition from monitoring to delivery.”

In some cases, children born with heart block require a pacemaker due to a dangerously low heart rate. Mikey’s heart rate was in the mid-50s in utero, well below the typical newborn rate of 130 to 150 beats per minute.

“After delivery on December 5, Mikey’s heart rate dropped below 50, and signs of distress emerged,” said Reina Tan, MD, Mikey’s pediatric cardiologist and electrophysiologist at Hassenfeld Children’s Hospital and an assistant professor in the in the . “We determined he would need a pacemaker as soon as possible.”

A Pacemaker the Size of a Large Vitamin

Typically, babies who need pacemakers must weigh at least 3 to 3.5 kilograms before they can receive a standard device. Mikey was far too small and would have needed to wait in the hospital with a temporary device until he grew. But Dr. Tan and her team had another idea. They turned to Medtronic’s Micra, a tiny, leadless pacemaker no bigger than a large vitamin and weighing about as much as a penny. The device had to be specially adapted for Mikey, transforming it into a version where it could be used as a pacemaker generator after pacing leads were attached to his heart.

The Micra has been FDA approved for adult use—the first U.S. adult implantation took place at ��ɫAV Langone Health in 2014 by pioneering cardiologist Larry A. Chinitz, MD, director of the Heart Rhythm Center—its adapted version for babies is not. Dr. Tan and the pediatric heart team at Hassenfeld Children’s Hospital established an emergency use approval when Mikey was born on December 5, 2024. Though pacemakers are used in adults, their use is extremely rare in children—especially in newborns. Only 1 in 20,000 children is born with heart block each year, and not all of them require a pacemaker.

“This is a unique situation,” said Dr. Tan. “Mikey is only 1 of 52 babies in the United States to receive this kind of pacemaker. He’s the first baby at ��ɫAV Langone and the first in the tristate area.”

Complex Care in the Operating Room and CCVCU

On December 17, 2024, T.K. Susheel Kumar, MD, pediatric cardiac surgeon in Hassenfeld Children’s Hospital’s Pediatric Congenital Heart Program and associate professor in the , worked alongside Dr. Tan to surgically implant the pacemaker.

“Not only was this an innovative procedure, but it was also a remarkable display of teamwork,” said Dr. Kumar. “We were able to help Mikey go home safely with his family as early as possible, where we can continue to monitor his heart with this small device.”

Following the successful surgery, Mikey recovered in Hassenfeld Children’s Hospital’s Congenital Cardiovascular Care Unit (CCVCU), where certified child life specialists, including Karissa Fischer, CCLS, and board-certified music therapists helped keep his and his parents spirits bright during the holiday season, thanks to the support of Sala Institute for Child and Family Centered Care. On January 2, 2025, he was able to go home to Long Island to meet his brothers for the first time.

“We are so grateful to the team at Hassenfeld Children’s Hospital for saving Mikey’s life and supporting me and my husband, Michael, every step of the way,” said Sarah.

Now at home with his two brothers, Mikey is thriving — a living testament to the power of innovation and teamwork in pediatric cardiology.

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Katie Ullman
Phone: 646-483-3984
Kathryn.Ullman@��ɫAVLangone.org