Paroxysmal supraventricular tachycardia (PSVT) is an episode where your heart suddenly starts beating very fast, typically between 150 and 220 beats per minute, then stops just as abruptly. The word “paroxysmal” means it comes and goes without warning. “Supraventricular” means the problem originates above the ventricles, in the upper chambers of the heart or the electrical tissue connecting the upper and lower chambers. PSVT affects roughly 2.25 out of every 1,000 people, with an estimated 89,000 new cases per year in the United States.
What Happens Inside the Heart
Your heart has a built-in electrical system that sends signals in a specific sequence to keep your chambers pumping in rhythm. In PSVT, an electrical signal gets caught in a loop. Instead of traveling its normal path and stopping, the signal circles back on itself and re-fires, driving the heart rate up to 150, 200, or even 250 beats per minute. This looping pattern is called a reentry circuit.
The most common type of PSVT involves a loop within the electrical junction between the upper and lower chambers of the heart (called the AV node). A less common type uses an extra electrical pathway that some people are born with, a connection between the upper and lower chambers that isn’t supposed to be there. This extra pathway is the mechanism behind Wolff-Parkinson-White syndrome, which is a specific form of PSVT. A third, rarer type originates from a single spot in the upper chambers firing too rapidly.
Who Gets PSVT
PSVT can develop at any age, but the pattern differs depending on whether someone has other heart conditions. People with “lone” PSVT, meaning no other heart disease, tend to be younger, with an average age of 37. Those who have PSVT alongside other cardiovascular problems are older on average, around 69. Women are disproportionately affected: 58% of women with lone PSVT first develop symptoms during their childbearing years, suggesting hormonal shifts play a role. Among men with PSVT, 90% also have other cardiovascular disease, compared to 48% of women.
What an Episode Feels Like
A PSVT episode typically starts without any warning. One moment your heart is beating normally, and the next it’s racing. The hallmark sensation is a sudden, forceful pounding or fluttering in the chest. Many people also feel a pulsing sensation in the neck. Beyond the palpitations, common symptoms include:
- Dizziness or lightheadedness
- Chest discomfort or pressure
- Shortness of breath
- Sweating
- Weakness or extreme tiredness
- Fainting or nearly fainting
The faster the heart rate climbs, the more intense these symptoms tend to be. Episodes can last seconds, minutes, or occasionally hours. They end as suddenly as they begin, often with an abrupt return to a normal heartbeat. Some people experience episodes rarely, perhaps once or twice a year. Others have them weekly.
Signs That Require Emergency Care
Most PSVT episodes are uncomfortable but not dangerous. However, certain signs suggest your heart isn’t pumping enough blood to your body and you need immediate help. These include chest pain, a decreased level of consciousness, severe shortness of breath, heavy sweating, and a systolic blood pressure dropping below 90 mmHg. Fainting during an episode also warrants emergency evaluation. Prolonged episodes that don’t resolve on their own, or situations where the diagnosis is uncertain, are other reasons to seek urgent care.
How PSVT Is Diagnosed
An electrocardiogram (EKG) taken during an episode is the primary diagnostic tool. PSVT produces a distinctive pattern: a fast, very regular rhythm with narrow electrical spikes. The regularity is a key feature, with virtually no variation between beats. The challenge is that episodes are unpredictable, so your heart may be beating normally by the time you reach a doctor’s office. In those cases, a portable heart monitor worn for days or weeks can capture an episode as it happens and confirm the diagnosis.
Stopping an Episode at Home
The first-line approach for stopping a PSVT episode is a set of physical techniques called vagal maneuvers. These stimulate a nerve that slows heart rate. The most well-known is the Valsalva maneuver: you bear down as if straining to have a bowel movement for about 15 seconds. A modified version adds a step where you lie flat and raise your legs immediately after straining, which increases the amount of blood returning to your heart and improves the technique’s effectiveness.
In one study, the standard Valsalva maneuver restored a normal rhythm in about 17% of patients, while the modified version succeeded in roughly 38%. Other vagal maneuvers include splashing ice-cold water on your face or briefly holding your breath. These techniques are safe to try at home when you recognize an episode starting, and many people with recurrent PSVT learn to stop episodes before they need medical help.
Treatment in the Emergency Room
When vagal maneuvers don’t work, an intravenous medication can interrupt the electrical loop almost instantly. This drug works by briefly blocking conduction through the AV node, essentially resetting the circuit. It’s given as a rapid push into a vein. The effect is dramatic: most people feel a brief but intense sensation of chest pressure or flushing, sometimes described as a “thud” in the chest, and then their heart snaps back to a normal rhythm within seconds. In patients whose blood pressure has dropped dangerously low or who are showing signs of shock, electrical cardioversion (a controlled shock delivered through pads on the chest) may be used instead.
Long-Term Management and Ablation
If episodes are infrequent and mild, many people manage PSVT without daily treatment, simply using vagal maneuvers when episodes occur. For people with frequent or disruptive episodes, daily medications that slow electrical conduction through the heart can reduce how often PSVT happens.
The most definitive treatment is catheter ablation, a procedure where a thin, flexible tube is threaded through a blood vessel (usually in the groin) up to the heart. The tip of the catheter delivers targeted energy to destroy the tiny area of tissue responsible for the electrical loop. The success rate is 90% to 95% for most types of PSVT. Recurrence happens in 2% to 11% of cases, and a second procedure can often resolve it.
Risks of ablation are uncommon but include bleeding or infection at the catheter insertion site, blood clots, and blood pooling under the skin. On rare occasions, the procedure can damage the heart’s normal electrical wiring, which would require a pacemaker. Cardiac tamponade, where fluid accumulates around the heart, is another rare but serious complication. Most people go home the same day or the next morning and return to normal activities within a few days.
Common Triggers
Many people notice that certain situations bring on episodes. Caffeine, alcohol, and stimulant medications are frequently reported triggers. Physical or emotional stress, sleep deprivation, and dehydration can also lower the threshold for an episode. Some people find that bending over, sudden position changes, or intense exercise sets one off. Identifying your personal triggers through a simple diary of episodes and what preceded them can help you reduce their frequency, even without medication.