Paroxysmal supraventricular tachycardia (PSVT) is a type of abnormal heart rhythm where your heart suddenly starts beating very fast, typically between 150 and 220 beats per minute. About 1 in 300 people in the United States have it, with roughly 1.26 million affected as of recent estimates. Episodes start and stop abruptly, sometimes lasting just a few seconds and other times stretching on for hours.
The word “paroxysmal” refers to these sudden bursts. “Supraventricular” means the problem originates above the ventricles (the heart’s lower chambers), in or near the upper chambers. PSVT is not the same as a heart attack, and most people with it have structurally normal hearts. But the episodes can be frightening and, when frequent, disruptive to daily life.
What Happens Inside the Heart
In a normal heartbeat, an electrical signal travels from the top of the heart to the bottom in an orderly sequence. In PSVT, that signal gets caught in a short circuit, looping around and around instead of following its usual path. Each loop triggers another heartbeat, which is why the rate shoots up so fast.
There are three main types, distinguished by where the short circuit forms:
- AVNRT (atrioventricular nodal reentry tachycardia): The most common type. Two pathways exist within or near the AV node, the heart’s electrical relay station. One pathway conducts signals slowly and the other quickly. A premature heartbeat can get trapped bouncing between these two pathways. In the typical form, the signal travels down the slow pathway and back up the fast one.
- AVRT (atrioventricular reentry tachycardia): An extra electrical connection, called an accessory pathway, bridges the upper and lower chambers. The signal loops between the normal conduction system and this extra bridge. Some people with AVRT show a telltale pattern on their resting heart tracing called preexcitation. Others have a “concealed” pathway that only conducts in one direction, so the resting tracing looks normal.
- Atrial tachycardia: A single spot in the upper chambers fires electrical signals too rapidly. This is less common than the other two types.
What Episodes Feel Like
The hallmark of PSVT is a sudden flip into a rapid heartbeat that feels like your heart is racing, pounding, or flip-flopping in your chest. Most people can pinpoint the exact second it starts. Beyond palpitations, common symptoms include chest discomfort, shortness of breath, dizziness, and lightheadedness. Some people faint. The faster the rate climbs, the more intense the symptoms tend to be.
Episodes can end just as abruptly as they begin. Some last only a few seconds, while others persist for minutes or even hours. Many people describe a sudden “thud” or brief pause in the chest when the rhythm snaps back to normal. Between episodes, most people feel completely fine.
Common Triggers
Many episodes seem to come out of nowhere. When triggers can be identified, they often include physical exertion, emotional stress, lack of sleep, and alcohol. Interestingly, caffeine at moderate intake levels has not been shown to make PSVT more likely or more severe. A controlled study that gave caffeine or placebo to patients undergoing electrophysiology testing found no significant difference in whether the arrhythmia could be triggered or how fast it ran. That said, individual sensitivity varies, and some people do notice a personal connection between caffeine and their episodes.
Who Gets PSVT
PSVT affects people of all ages, including children. Rates are highest in older adults and in women. The estimated incidence in the US is about 58 new cases per 100,000 people each year. Many people experience their first episode in their teens or twenties, though a first episode can happen at any age.
How It’s Diagnosed
The key diagnostic tool is an electrocardiogram (ECG). During an episode, a PSVT tracing typically shows a fast, regular rhythm with narrow electrical complexes. In AVNRT specifically, the P waves (which represent the upper chambers contracting) are often invisible because the upper and lower chambers activate almost simultaneously. When P waves do appear, they may show up as tiny extra bumps tucked into other parts of the tracing.
The challenge is catching an episode in progress. If your episodes are infrequent, your doctor may have you wear a portable heart monitor for days or weeks to record what happens when your heart races. An electrophysiology study, where thin wires are threaded into the heart to map its electrical activity, can identify the exact type of PSVT and the location of the short circuit.
Stopping an Episode at Home
Because PSVT depends on a looping electrical circuit, anything that briefly interrupts conduction through the AV node can break the loop. Vagal maneuvers do exactly this by stimulating the vagus nerve, which slows electrical conduction through that relay station.
The most well-known technique is the Valsalva maneuver: bearing down as if straining on the toilet for about 15 seconds. A modified version adds a step where you lie flat and have someone raise your legs immediately after straining. In a randomized trial, the modified approach restored normal rhythm in about 43% of patients, compared to roughly 11% with the standard technique. Other vagal maneuvers include splashing ice-cold water on your face or briefly immersing your face in cold water.
Medical Treatment for Acute Episodes
When vagal maneuvers don’t work, the first-line treatment in an emergency setting is an intravenous medication that temporarily blocks electrical conduction through the AV node. It works within seconds and wears off almost as quickly. Most people feel a brief, uncomfortable sensation of chest pressure or flushing that passes in under a minute. If the first dose doesn’t work, a second, larger dose is given.
For people with an accessory pathway that conducts signals in a dangerous pattern (pre-excited atrial fibrillation), certain common heart-rate-lowering medications, including some calcium channel blockers, beta-blockers, and digoxin, are actually harmful and should be avoided. Current guidelines are clear on this point.
Long-Term Management Options
If episodes are rare and well tolerated, some people simply learn to manage them with vagal maneuvers and don’t need ongoing treatment. For those with frequent or bothersome episodes, there are two main paths.
Daily medications such as certain calcium channel blockers or beta-blockers can reduce the frequency and severity of episodes. Current European guidelines rate these as reasonable options for AVNRT, though they’ve been slightly downgraded in recommendation strength compared to earlier guidelines. Some people take a “pill in the pocket” approach, carrying a dose of medication to take only when an episode starts.
Catheter ablation is the most definitive treatment. A thin catheter is guided into the heart, and targeted energy (usually radiofrequency heat) destroys the tiny area of tissue responsible for the short circuit. Success rates are high: around 98% to 99% for the most common PSVT types. Recurrence rates after the procedure are low, in the range of 4% to 6% over a year or more of follow-up. Current guidelines recommend that catheter ablation be offered as a first-choice option for all reentrant types of PSVT, after a thorough discussion of risks and benefits. For most people, it eliminates the arrhythmia permanently in a single procedure.
Living With PSVT
PSVT is rarely life-threatening, but the episodes can significantly affect quality of life. The unpredictability of when the next one will strike leads some people to avoid exercise or social situations. Knowing how to perform vagal maneuvers gives you a reliable first response. If episodes are interfering with your daily routine, ablation offers a cure rate that few other cardiac procedures can match, with a recovery period of just a few days for most people.