Paroxysmal supraventricular tachycardia (PSVT) is a type of rapid heart rhythm that starts and stops suddenly (paroxysmal), originates above the ventricles (supraventricular), and produces a fast regular heart rate, typically between 150 and 250 beats per minute. It is one of the most common arrhythmias seen in clinical practice and can affect people of all ages, including those with structurally normal hearts.
PSVT is caused by an abnormal electrical circuit or pathway above the level of the ventricles. The most common mechanism is re-entry within or around the atrioventricular (AV) node, where an electrical impulse circles repeatedly, driving the ventricles at a rapid rate. Episodes typically start abruptly, often triggered by exertion, caffeine, or stress, and end just as suddenly, either spontaneously or with intervention.
Symptoms include sudden-onset palpitations, a racing or pounding heartbeat, dizziness, breathlessness, and occasionally near-fainting. PSVT is rarely life-threatening in people with a structurally normal heart, but it can be frightening and significantly affect quality of life. It is important to distinguish PSVT from more dangerous arrhythmias, particularly ventricular tachycardia.
Initial management of an acute episode includes vagal manoeuvres (such as the Valsalva manoeuvre or carotid sinus massage), which slow conduction through the AV node and can terminate the arrhythmia. If these fail, intravenous adenosine is given in hospital. Long-term options for recurrent PSVT include medication (such as beta-blockers or verapamil) or catheter ablation, which can be curative in over 95% of suitable cases. See also: Supraventricular Tachycardia (SVT).
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