Patient stories for
Freezor™ and Freezor™ Xtra for pediatric AVNRT

Triple the impact: Identical triplets receive Medtronic cryoablation for a life-threatening heart condition. Inspired by their own experience, the sisters give back by working in healthcare.

Alyssa Jensen, Hannah Nelson, and Nicole Kriewall are identical triplet sisters from Rochester, Minnesota. All three were well on their way to becoming collegiate softball players as three-sport athletes at Lourdes High School. As seemingly healthy, athletic 17-year-olds, the last thing they thought they had to be concerned with was their heart health. 

Identical triplet teenage sisters standing together wearing purple softball shirts

“I was the first of us to notice it,” Alyssa said. “I would have these incidents where it felt like my heart was literally beating out of my chest. I remember asking my sisters, ‘Does this happen to you? Is this normal?’ and they both said, ‘Oh yeah, that happens to me too.’”

In fact, this was not normal, and all three sisters were diagnosed with atrioventricular nodal reentrant tachycardia (AVNRT). AVNRT is one of the most common forms of supraventricular tachycardia (SVT) and causes a very rapid and life-threatening abnormal heart rhythm. Not only that, but nearly 35% of AVNRT cases occur in pediatric patients and incidence increases with age. This places a tremendous burden on a patient’s life and can impact cognitive and emotional development.

All three of their nearly identical hearts were experiencing episodes of AVNRT, despite being otherwise healthy, active teenagers. These symptoms went on for almost four years, starting their first year of high school. Each sister can think back on moments when they experienced AVNRT episodes. 

"I remember feeling like I was going to pass out during one of my soccer games,” Nicole said. “I had to sub off and put my feet up. I think because all three of us experienced this, it went without notice, we thought it was normal."

Luckily for these sisters, their mom was a nurse at Mayo Clinic.

“I remember our mom coming home from a work conference where they talked about abnormal heart rates,” Alyssa said. “'Does your heart still do that thing where it beats out of your chest?'” 

This led Dawn Nelson to take all three of her daughters to see Dr. Bryan Cannon, a pediatric cardiologist and electrophysiologist (EP) at Mayo Clinic.

“We were in the middle of our senior season of sports, and we were all captains,” Hannah said. “I remember being the most concerned about being able to finish my hockey season and start my senior season of softball. I wanted to be a collegiate athlete; I don’t think I even understood the potential severity of the issue.” 

When Dr. Cannon diagnosed the sisters with AVNRT, they were looking for a treatment option that would allow them to continue their active lifestyles with as little disruption as possible. 

Identical triplet sisters standing together wearing costumes

The Nelson triplets as toddlers.

“My mom did a really great job of advocating for us,” Hannah said. “I remember the conversation was basically: here’s the issue, and here’s the solution.” 

Dr. Cannon felt that the appropriate therapy for the triplets was a cardiac cryoablation with the Medtronic Freezor Xtra cardiac cryoablation catheter and would allow all three girls to get the therapy needed in time to start their spring softball season. 

“I recommended cryoablation for the Nelson sisters because we needed a long-term solution for what could be a short-term problem, with the right treatment,” Dr. Cannon said. “I knew how important it was for them to be able to get back to doing what they loved as kids, which was sports. Medtronic cryoablation was the best choice to get them back in the game of life, and softball, as soon as possible.”

“I remember after the surgery feeling like, ‘I’m fine now,’” Alyssa said. “And I can’t think of a single episode I’ve had since we underwent the ablation.”

Not only do the sisters live full, active lives, but both Nicole and Alyssa now work in healthcare. Nicole is a nurse; she now works on the Mayo Clinic Covid Care Team but started her career in the pediatric intensive care unit (PICU) at Mayo where she worked with Dr. Cannon and his patients. 

“I don’t think you can grow up in Rochester and not consider healthcare as a career, Mayo was our playground,” Nicole joked. “But I do remember the night of the procedure I stayed up and talked with my nurse. He just sat there and talked to me about what I wanted to do after my procedure and what I was interested in. He made me feel really at ease. That nurse will never know it, but he impacted who I wanted to be.”

Identical triplet teenage sisters standing together in gray sweatshirts at a ballpark

The Nelson triplets pictured during their most recent season of slow pitch softball (2021), where they still play competitively together.

Alyssa, who is a certified surgical assistant at Mayo Clinic, said this procedure, as well as an ACL repair, inspired her to consider the healthcare field.

“There’s this instant gratification feeling when you complete a surgery. You feel like you’re making a difference,” said Alyssa.

Freezor and Freezor Xtra catheters are the only ablation catheter devices approved by the U.S. Food and Drug Administration (FDA) for pediatric* AVNRT. The FDA worked alongside Pediatric & Congenital Electrophysiology Society (PACES) to approach Medtronic requesting a pediatric approval, as part of the FDA pediatric device access initiative. The Freezor and Freezor Xtra catheters were identified as a key FDA priority for pediatrics, expanding the indication to specify the pediatric population, due to their safety profile. The unique cryomapping feature enables physicians to confirm and test the treatment site prior to ablation, supporting a safe and effective procedure for these delicate anatomies. The FDA’s commitment to removing obstacles for the development of pediatric-specific technology was the catalyst in this approval. 

As for the Nelson triplets’ own story involving the treatment with the Freezor Xtra catheter technology, Alyssa, a mom with her second child on the way, stressed the importance of sharing their experience and growing awareness of their therapy, particularly to parents and caregivers. 

“Our story is a great example of parents listening to their kids and taking them seriously when they say something feels off,” she said. “Not every kid is willing to say something isn’t right, so the more information and more options that are out there, the easier it will be to provide all kids with a better, healthier life.” 

Patients are at the core of the Medtronic Mission. This indication expansion will help fill an unmet need: safe, effective cardiovascular devices approved for pediatric use. Over 15 years of experience and evidence using the Freezor and Freezor Xtra catheters to effectively treat arrhythmias enabled Medtronic to prove the safety and efficacy needed to expand the indication to include some of the most important patients, children. This solidifies the Medtronic commitment to the EP space and to restoring life’s rhythm in patients big and small.

*Indicated for patients over two years of age.

This patient testimonial is based on these individuals' experience. The experience other individuals have with the therapy could be different. Experiences vary. Please talk to your doctor about your condition and the risks and benefits of this therapy.