Paroxysmal supraventricular tachycardia (PSVT) is episodes of rapid heart rate that start in a part of the heart above the ventricles. "Paroxysmal" means from time to time.
PSVT; Supraventricular tachycardia
Normally, the chambers of the heart (atria and ventricles) contract in a coordinated manner.
The contractions are caused by an electrical signal that begins in an area of the heart called the sinoatrial node (also called the sinus node or SA node).
The signal moves through the upper heart chambers (the atria) and tells the atria to contract.
After this, the signal moves down in the heart and tells the lower chambers (the ventricles) to contract.
The rapid heart rate from PSVT may start with events that occur in areas of the heart above the lower chambers (ventricles).
PSVT can develop when doses of the heart medicine, digitalis, are too high. It can also occur with a condition known as Wolff-Parkinson-White syndrome, which is most often seen in young people and infants.
A physical exam during a PSVT episode will show a rapid heart rate. It may also show forceful pulses in the neck.
The heart rate may be over 100, and even more than 250 beats per minute (bpm). In children, the heart rate tends to be very high. There may be signs of poor blood circulation such as light-headedness. Between episodes of PSVT, the heart rate is normal (60 to 100 bpm).
An ECG during symptoms shows PSVT. An electrophysiology study (EPS) may be needed for an accurate diagnosis and to find the best treatment.
Because PSVT comes and goes, to diagnose it patients may need to wear a 24-hour Holter monitor. For longer periods of time, another tape of the rhythm recording device may be used.
PSVT that occurs only once in a while may not need treatment if you don't have symptoms or other heart problems.
You can try the following techniques to interrupt a fast heartbeat during an episode of PSVT:
Valsalva maneuver. To do this, you hold your breath and strain, as if you were trying to have a bowel movement.
Coughing while sitting with your upper body bent forward.
Splashing ice water on your face
You should avoid smoking, caffeine, alcohol, and illicit drugs.
Emergency treatment to slow the heartbeat back to normal may include:
Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.