PSVT

Paroxysmal supraventricular tachycardia (PSVT) is a type of rapid heart rhythm that starts and ends suddenly and originates above the ventricles. Episodes typically produce a sudden onset of a fast, regular pulse, often between 150 and 250 beats per minute, with accompanying symptoms such as palpitations, lightheadedness, shortness of breath, chest discomfort, or fainting. PSVT can affect people of all ages but is most commonly seen in children, young adults, and those with no structural heart disease.

Most PSVTs arise from reentry circuits within or near the atrioventricular (AV) node or from a fast accessory pathway between the atria and ventricles. The two main types are AV nodal reentrant tachycardia (AVNRT) and AV reciprocating tachycardia (AVRT), the latter often associated with an accessory pathway as seen in Wolff-Parkinson-White syndrome. A smaller subset originates from focal atrial tachycardia.

Diagnosis is typically made during an episode with a 12-lead electrocardiogram showing a narrow-complex tachycardia. Confirmatory monitoring may involve ambulatory ECG recording. Vagal maneuvers (such as the Valsalva maneuver) can terminate many episodes; adenosine is commonly used in the acute setting. If the patient is unstable, synchronized electrical cardioversion is indicated. Chronic management may involve medications such as beta-blockers or non-dihydropyridine calcium channel blockers to reduce episodes. For ongoing or recurrent PSVT, radiofrequency catheter ablation of the reentry circuit or accessory pathway offers a curative option with high long-term success rates.

Prognosis is generally favorable, especially after ablation, though recurrence can occur in some individuals. PSVT is typically not life-threatening in the absence of underlying heart disease.