Brainna McCormick was warming up for a high school basketball game last December when she noticed something wasn't right. An accomplished athlete, McCormick knows her body so when her heart started racing she knew something was wrong.
"I felt like I was going to black out. I thought if I just get in the game and moving everything will settle down, but that didn't happen. I told my coaches and took myself out of the game," McCormick said.
Her dad, Tony McCormick, knew something was very wrong when his daughter pulled herself out the game. They called an ambulance and she was admitted to the Ronald McDonald Children's Hospital at Loyola University Medical Center.
She was diagnosed with supraventricular tachycardia (SVT), an issue with the heart's electrical system that causes a rapid heart rhythm. It can cause the heart to beat at least 100 beats per minute and may reach 300 beats per minute.
"SVT is typically not life-threatening. Still, we did a complete work-up on her since this was her first episode to just make sure everything was OK and all the tests came back normal. Since Brianna is a very athletic person and really understands her body we felt comfortable just keeping an eye on it and seeing if it happened again," said T. Marsha Ma, MD, pediatric cardiologist at Loyola University Health System.
Brianna's episode ended quickly. She was released from the hospital and returned to her active teenage life, but in April during a softball game the symptoms appeared again.
"It was during warm-ups that I started to feel it again. I noticed that I was extremely tired, but thought it was just from a long day at school," McCormick said. "I went to field a groundball and my heart started beating extremely fast again. It just kept getting worse and I couldn't make it stop so I went back to the hospital."
"This time she needed medication to stop the SVT. Since this was her second episode, I had a conversation with the family to discuss what options they had to treat the SVT," Ma said.
Initially, the family decided to try oral medication to help control McCormick's heart rate, but they were difficult for an athlete.
"They didn't just slow down my heart rate, they slowed everything down. I couldn't concentrate; I couldn't do my homework or sports. All I wanted to do was sleep," McCormick said.
Ma referred the McCormicks to Frank Zimmerman, MD, Loyola pediatric cardiologist and expert in pediatric clinical electrophysiology.
"Brianna is quite the athlete and you expect her to have an increased heart rate when participating in sports, but her episodes would happen without activity and this was a sign that it would continue without medication or treatment," Zimmerman said.
According to Zimmerman three out of 1,000 children get SVTs and the symptoms and frequency may increase as the child gets older. Though the cause of SVTs varies and it's not preventable, there are treatment options that are low risk and allow people to return to normal activities.
In July, Zimmerman performed an electrophysiology study which reproduces SVT symptoms in a lab setting. The test allowed him to locate the group of cells that were causing McCormick's rapid heart rate. He then performed a catheter ablation, a minimally invasive procedure that destroys areas of heart tissue that are responsible for the erratic electrical signals. A catheter (thin flexible tube) is guided through blood vessels to the heart. The tip of the catheter delivers radiofrequency energy that heats and destroys tissue.
"When I first thought of having it done I was nervous, but Dr. Zimmerman made me feel really comfortable. He was really nice and I felt like I didn't have to worry because he knew what he was talking about," McCormick said. "Now, I feel back to normal. Before, I was always thinking about it and nervous that it would slow me down, but it doesn't affect me anymore. I can keep playing sports and not worry about it."
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