SVT: The underdiagnosed heart condition that affects thousands of Americans.

I was a healthy teenager. I played soccer almost every day, I ran long distance for my high school track team, I thought I was at the peak of my physical health. Then one day in my history class, I thought I was having a heart attack. Out of nowhere, my heart began racing like I was in a full sprint, I started to get lightheaded, and I began to panic. Not knowing what to do, I asked to be excused, and rushed to the nurse’s office, but by the time I got there, my heart was totally back to normal. The nurses checked my vitals and sent me home for the day. 

 

Worried something was seriously wrong, I made an appointment with a cardiologist. He had me wear a heart monitor for a month, during which time I had more of these frightening episodes. I would be in the middle of a soccer game, or at my job at a local ski hill, when my heart would race so fast I couldn’t count the beats. After looking at the results, I was diagnosed with a common but seldom known condition, SVT.

 

 

THE CONDITION:

 

Supra ventricular tachycardia, more commonly known as SVT, describes several arrythmias originating in the upper chambers of the heart. According to a National Institute of Health study, a little over 2 in 1000 Americans will have SVT in their lives.

 

SVT is characterized by a sudden spike in heart rate, caused by the electrical signals in someone’s heart getting stuck in a loop. The heart races at up to 250 beats per minute, for as little as a few minutes to hours, then will suddenly return to normal rhythm.

 

An episode can be brought on by several factors, caffeine or alcohol consumption, exercise, or like my first episode, for seemingly no reason at all.

 

SVT is a blanket term that applies to several conditions, such as Wolf Parkinson White Syndrome (which I had), Atrial tachycardia and AVNRT.

 

Wolf Parkinson White Syndrome, or AVRT is one of the more common forms of SVT, stemming from a congenital extra piece of electrical circuitry in the heart. Though between one and three out of every thousand people are born with the condition, only about half of them will present symptoms. 

 

Dr. Cyrus Hadadi is an electrophysiologist at MedStar Washington Hospital in Washington DC, and performs radiofrequency ablations to correct SVT, including my own procedure.

 

“I think that’s some combination of physicians not always diagnosing patients correctly, but also you can have the anatomy to support SVT, but you don’t necessarily go into SVT, for reasons that are not totally clear to us,” said Hadadi.

 

Though SVT by and large is not overly dangerous, it does carry some risks, and can interfere with someone’s life day to day. The increased heartrate brought on by SVT can cause someone to lose consciousness, and in severe cases SVT can wear down muscles in the heart over time. Beyond the physical risks many patients experience immense anxiety during episodes and can keep them from engaging in exercise or activities for fear of an episode. I stopped running after my diagnosis, afraid what could happen if I had an episode on remote trail or roadside.

 

 

Some patients with SVT can have episodes on a weekly or even daily basis, while others could go years between episodes.

 

 

AN UNDERDIAGNOSED CONDITION:

 

Despite being relatively common, SVT is not a widely known condition.

 

Dr. Jim Cheung, Chair of the American College of Cardiology Electrophysiology Council, believes SVT is underdiagnosed, as it can be hard to catch with many tests, and is often mistaken for a panic attack. “The thing with a lot of these arrythmias is they happen very sporadically,” says Cheung, “some people with SVT only have an episode lasting 30 minutes once every several years and so they go see a doctor they will get an echocardiogram which is usually normal. They may where a monitor for a month but if that happens to be a month where they are nor having the arrythmia it will be totally missed.”

 

 However, Dr. Cheung has seen a rise in diagnoses in recent years. New technology and products for people to monitor their health has made this at times elusive condition more recognizable.

 

“In the era of digital health, the use of smart watches, is helping patients take control of their diagnosis and allow them to record some of these episodes and be able to seek medical attention,” said Cheung. With the proliferation of smart health devices such as the Apple Watch, more people are able to recognize their arrythmias and get more focused care for the issue. 

 

Heart disease is generally conceptualized as an issue in middle-aged to senior individuals, but SVT affects people regardless of age.

 

Ava Cumberbatch was 16 the first time she experienced SVT in the summer of 2020. During a soccer practice, she felt light-headed, and her coach recommended getting her heart checked. She was then diagnosed with SVT as well as left ventricular noncompaction cardiomyopathy (LVNC). 

 

“I never broke a bone, not even so much as fractured something got the bad bruise that's about it and so it was surprising,” said Cumberbatch, “to think although it was something easy that could be managed it wasn't bad, I never thought I was invincible but it kind of made me feel like oh wow like I guess I can I be injured or something can be wrong with me physically.”

 

 

A SIMPLE FIX:

 

SVT is a frightening condition, but one that can be well managed. For some, no medication or surgical intervention is even required. Cumberbatch takes medication to prevent going into SVT and has had fewer and shorter episodes. Others who have very infrequent episodes may choose not to treat it at all and use various physical maneuvers to break episodes when they occur.

 

Finally, there is a procedure to potentially cure it, cardiac ablation. Cardiac ablation is a procedure wherein catheters (essentially long wires) are inserted into the body, normally through the groin or thigh, and traverse through the femoral vein to the heart where a team of technicians create a three-dimensional map of the heart and locate the electrical issue. The physician will then heat the tip of the catheter and destroy the faulty circuitry, hopefully breaking the short circuit and taking away the hearts ability to enter SVT. I had this procedure done in July of 2023.

 

Catheter ablation has a high success rate, ranging from 90-95% according to the Cleveland Clinic. Some patients do require multiple ablations, but for many this simple procedure can either greatly reduce or completely remove the condition.

 

“This is a curative procedure, the success rates are extremely high, “said Dr. Cheung, “it’s one of those rare procedures where we can tell the patient once everything is taken care of that they can basically pretend that they never had it.”

 

Ablation is used to treat a variety of rhythm disorders, including SVT and Afib.

 

I had my own procedure done at Medstar Washington Hospital. I was admitted into the electrophysiology ward, prepped for surgery then brought in for the procedure. I was put into a “twilight state” where I remained conscious but sedated while Dr. Hadadi and his team inserted the catheters and began mapping my heart. They then would inject me with adrenaline to trigger SVT and use the catheters to find the circuitry in my heart, and then ablate it to remove the pathway.

 

The procedure lasted roughly 3 hours, after which they observed me for a period, and then released. I could walk that same day, and aside from soreness in the sight of insertion, I felt totally fine.

 

THE OUTLOOK:

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I completed my own cardiac ablation in July 2023, and so far, I have had no episodes. I can play soccer again or drink coffee without worrying about my heart rate skyrocketing. The technology to treat and recognize SVT is only improving with time and as more patients are able to recognize their symptoms, they will bae able to seek out the care they need to handle their condition.

 

“You know, one in in 500 doesn't seem like a lot, but there's 300 million Americans,” Dr. Hadadi said, “so think about how much SVT there really is in our country and in our community. SVT can be very, very symptomatic, but it can be cured, so you don't have to live with it.”

 

SVT can be scary, but the hardest thing is to be able to recognize it to seek out appropriate care.