Speed, Expertise and Advanced Technology Combine to Save an Infant's Heart

Meet Fletcher St. Jean, the youngest child to receive an EV-ICD device to manage idiopathic ventricular fibrillation

CINCINNATI, April 23, 2026 /PRNewswire/ -- Perhaps the most rewarding aspect of watching 1-year-old Fletcher St. Jean toddling after his brothers and sisters is that he doesn't realize or even care that there's a page in the medical history books bearing his name.

"He's doing really well. You would almost never know that he had anything done," says Zach St. Jean, Fletcher's father.

The situation was different in June 2025 when Zach and Jordan St. Jean brought their month-old son to the emergency department at Cincinnati Children's Liberty Campus. Their son had been running a fever and was getting sicker.

But even then, no one expected Fletcher would become the youngest and smallest child to ever receive an extravascular implantable cardioverter-defibrillator (EV-ICD)—a device needed to protect his heart from suddenly stopping.

His case started as a significant but straightforward urinary tract infection caused by exposure to E.coli bacteria. An infusion of antibiotics would clear things up. But while he was being treated at the hospital, Fletcher suddenly went into ventricular fibrillatory arrest.

Jumping into high gear, the emergency medicine team at the Liberty Campus rapidly and successfully revived the infant boy with an external defibrillating shock.

"We were really fortunate that we were already in the hospital when it happened," Zach recalls.

Big medicine for a little boy

The numbers are not precise, but experts estimate that about 350 to 500 infants across the United States die each year from sudden cardiac death linked to structural heart conditions. Overall, an estimated 1 in every 22,000 children have a heart condition that requires defibrillation.

It turns out that the highest risk for these emergencies occurs in boys, with 90% of cases occurring before 6 months.

Once stabilized, Fletcher was transported to Cincinnati Children's Burnet Campus, where a large team of clinicians conducted an extensive work-up to determine why his heart stopped. There was no known family history of inherited heart defects, nor was there a clear sign that the infection was bad enough to cause such a severe reaction. He did not have any allergies to the antibiotics used.

Nevertheless, Fletcher continued to experience rapid, chaotic heartbeats. Essentially, the lower chambers of his heart would begin quivering without explanation--resulting in the diagnosis of idiopathic ventricular fibrillation (IVF).

To prevent another sudden heart stoppage, Fletcher would need a special device—an ICD. These internally implanted devices use electrical leads to provide either pacing or a shock to the heart to "break" the arrhythmia and restore normal rhythm.

The problem: nearly all these devices are designed for adult-sized bodies. Even in the rare cases when children need them, the patient generally needs to weigh at least 70 pounds. Some externally wearable defibrillators exist for smaller children, but these are not available for infants.

Sending Fletcher's parents home with a portable automatic external defibrillator (AED) also was not an option because those devices are suitable only for children weighing 40 pounds or more.

Fletcher weighed about 10 pounds when his heart stopped.

Cincinnati Children's-led research makes clinical impact

Experts at Cincinnati Children's were familiar with a new device made by Medtronic called the Aurora EV-ICD™ System. But none of the system elements—the device, the lead wires, nor the tools used to "tunnel" the lead under the breastbone had been reported for infant use, says Chad Connor, MD, the pediatric electrophysiologist who ultimately implanted the device.

But figuring out ways to make big devices fit in little spaces has been a special interest for years among cardiac researchers at Cincinnati Children's. In fact, experts here have developed a set of 3D-imaging tools that have made it possible to determine whether a child's chest cavity can accommodate cardiac devices, including left-ventricular heart pumps, that normally come with arbitrary age and weight limitations.

While Fletcher remained under close watch in the hospital's cardiac ICU, Sassan Hashemi, MD, another member of Division of Pediatric Cardiothoracic Surgery at Cincinnati Children's performed a critical task. Using imaging data from Fletcher's chest CT scan, Hashemi constructed a 3D model of Fletcher's heart and chest cavity. The process took less than a day.

The 3D results mattered because if the surgical planning had considered only a flat 2D plane, there would not have been enough room to fit a critical 9-cm portion of the device's lead. But by curving the wire in both vertical and horizontal ways there was just enough room, Connor says.

"This procedure would not have been possible without the 3D model," Connor says. "It demonstrated that the lead could fit in the desired space and allowed for virtual trialing of multiple positions within the chest."

A successful outcome

Fletcher's procedure was performed June 6, 2025. He was a month and a half old.

We made the decision within a few days of him arriving," Zach recalls. "But they were waiting for two things, one, to clear the infection out of his system before surgery, and two, they wanted him to grow a little bit more because he was a little small still to be receiving that device." 

The device and battery were placed in Fletcher's abdomen below the rib cage, with the single, critical lead wire snaking vertically just below his breastbone to sit just in front of the heart but not directly attached to the heart tissue.

Fletcher went home six days later.

Fletcher does not have the large chest scar that occurs from open heart surgery. He has no wires emerging from his torso to connect to external batteries. The family and the clinical team have remote access for monitoring the device as well.

Otherwise, Fletcher is free to be a boy.

"He should probably avoid regular heavy contact sports like football or boxing, but he can run, swim, bike, or play soccer without restriction," Connor says.

Connor also says the minimally invasive procedure was clearly preferable to "plan B." If the Aurora device could not be implanted, Fletcher would have needed a procedure called an epicardial implant via sternotomy.

That involves cutting the breastbone and implanting a device with two wires that attach directly to the heart. This open surgery comes with more complication risks and a longer recovery time compared to implanting the Aurora EV-ICD, Connor says. Complications occur within five years in about 35% of cases involving epicardial implants. And that would not count future open surgeries Fletcher would need anyway to replace leads as he grows.

With the newer device, the curves the surgical team left in the lead may provide some slack as Fletcher grows, potentially delaying the need for lead replacement. Even so, Fletcher will still need more procedures to replace the lead wires before he reaches his full height. Importantly, those procedures will likely be far less invasive than a repeat sternotomy.

For the family, making the choice to attempt the youngest-ever EV-ICD device implantation was fairly simple.

"They did a good job of educating us," Zach says. "They explained the concept of the device and that it had been done for older kids, but not on anybody his age yet. And they gave the option of multiple different devices. So it ultimately came down to what we felt most comfortable with."

Zach says he was thankful for all the care the Cincinnati Children's team provided.

"All the nurses and doctors and all the staff were phenomenal throughout the whole process," he says. "Everybody helped however they could and went above and beyond. I mean, it was everything you could hope for."

Learn more about 3D virtual surgical planning at Cincinnati Children's

Learn more about Cincinnati Children's work to support developing more child-sized medical devices

SOURCE Cincinnati Children's Hospital Medical Center