Supraventricular tachycardia (SVT) typically produces a heart rate between 150 and 220 beats per minute, though rates can fall anywhere above 100 bpm. A normal resting heart rate sits between 60 and 100 bpm, so SVT represents a dramatic and often sudden jump that most people notice immediately.
Typical Heart Rate During SVT
The hallmark of SVT is a rapid, regular heartbeat that starts and stops abruptly. Most episodes land in the 150 to 220 bpm range, but the full spectrum depends on which type of SVT you’re experiencing. The three most common types each have slightly different rate profiles:
- AVNRT (the most common type): 118 to 264 bpm, though most people fall between 120 and 200 bpm. Rates above 200 are more likely in younger adults.
- AVRT (associated with an extra electrical pathway): 124 to 256 bpm.
- Atrial tachycardia: 100 to 250 bpm on the atrial side, though the rate the ventricles actually pump at can vary.
These ranges overlap considerably, which is why doctors rely on an EKG rather than heart rate alone to determine the specific type.
SVT Rates in Children and Infants
Children have naturally faster heart rates than adults, so the thresholds shift upward. SVT is suspected in infants when the heart rate exceeds 200 bpm, and in older children and teenagers when it exceeds 160 bpm. An infant’s normal resting rate can be 100 to 160 bpm on its own, which is why the SVT cutoff sits higher than the adult threshold.
How SVT Differs From a Normal Fast Heart Rate
Exercise, stress, fever, and dehydration can all push your heart rate well above 100 bpm. This normal response is called sinus tachycardia, and it behaves very differently from SVT even when the numbers look similar.
The simplest rule of thumb: your maximum predicted sinus rate is roughly 220 minus your age. A 40-year-old could reach about 180 bpm during intense exercise, while a 70-year-old tops out around 150 bpm. A heart rate that exceeds this formula, especially at rest, points strongly toward SVT rather than a normal physiological response.
Beyond the raw number, the pattern matters. Sinus tachycardia builds gradually and slows down gradually. It fluctuates with breathing, posture changes, and hydration. SVT, by contrast, flips on like a switch. One moment you’re at 80 bpm, the next you’re at 180. When it stops, it breaks suddenly rather than tapering off. If you’ve ever felt your heart abruptly start racing and then just as abruptly snap back to normal, that on-off behavior is a classic SVT signature.
Vagal maneuvers like bearing down (the Valsalva technique) also reveal the difference. They may gently slow sinus tachycardia by a few beats. With SVT, they either have no effect at all or they abruptly terminate the episode entirely. There’s no middle ground of gradual slowing.
How Rate Affects Symptoms
The faster your heart beats during SVT, the less time it has to fill with blood between contractions. This is why symptoms intensify at higher rates. At 150 bpm, you might feel palpitations and mild lightheadedness. At 200 bpm or above, dizziness, chest pressure, shortness of breath, and near-fainting become more likely.
Rate alone doesn’t determine severity, though. Your age, whether you have existing heart or lung disease, and how long the episode lasts all play a role. A healthy 25-year-old may tolerate a rate of 200 bpm with only uncomfortable palpitations, while an older adult with heart disease could become unstable at 160 bpm. Duration matters too. A 30-second burst at 180 bpm is very different from an episode that persists for hours at the same rate.
What Happens at Very High Rates
In emergency settings, a heart rate well above 150 bpm with signs of instability (low blood pressure, altered consciousness, severe chest pain) triggers more urgent intervention. Rates in the 200-plus range are more likely to compromise blood flow, particularly if the episode doesn’t resolve on its own or with simple vagal maneuvers.
For most SVT episodes, the heart’s structure is normal and the rhythm corrects itself or responds to treatment without lasting damage. The rate, however fast it gets during an episode, doesn’t typically cause permanent harm to the heart when episodes are short-lived. Prolonged SVT lasting hours to days is a different situation, as sustained high rates can gradually weaken heart muscle over time if left untreated.