Paroxysmal supraventricular tachycardia
Paroxysmal supraventricular tachycardia is a sudden-onset, regular narrow-complex tachycardia from a reentrant circuit involving the AV node (AVNRT) or an accessory pathway (AVRT), presenting with abrupt palpitations. Acute treatment is vagal maneuvers then adenosine, unstable patients receive synchronized cardioversion, and catheter ablation is a curative long-term option.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: paroxysmal supraventricular tachycardia (PSVT) is an abrupt-onset, regular, narrow-complex tachycardia arising from a reentrant circuit at or above the AV node.
- Epidemiology
Common, often first appearing in young, otherwise healthy adults.
- Risk factors
AV nodal dual physiology (for AVNRT) and congenital accessory pathways (for AVRT).
- Pathophysiology
Reentry: a self-sustaining circuit depolarizes the ventricles repeatedly at a fixed rate.
- Clinical features
Abrupt palpitations: sudden onset and offset, with a rapid regular pulse.
- Differential diagnosis
Atrial fibrillation: irregularly irregular (atrial fibrillation).
- Diagnosis
Establish with an ECG showing a regular narrow-complex tachycardia of abrupt onset: the diagnostic basis is a 12-lead ECG (or rhythm strip) demonstrating a regular narrow-QRS tachycardia at 150 to…
- Management
First, vagal maneuvers: Valsalva (ideally the modified leg-lift technique) or carotid sinus massage to terminate the arrhythmia.
- Complications
Symptom burden and recurrent episodes. Hemodynamic compromise or syncope at very rapid rates or with structural disease.
- Prognosis
Excellent: usually benign, and catheter ablation is curative in the large majority.
- Prevention
Avoid triggers: caffeine, alcohol, and stimulants.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Supraventricular tachycardia
Supraventricular tachycardia is any tachyarrhythmia arising at or above the AV node, usually a regular narrow-complex tachycardia. Acute management of a stable regular narrow-complex SVT is vagal maneuvers then adenosine; unstable patients receive synchronized cardioversion, and definitive therapy is catheter ablation.
- Atrial fibrillation
Atrial fibrillation is a supraventricular tachyarrhythmia with disorganized atrial activation and an irregularly irregular ventricular response, the most common sustained arrhythmia and a major cause of stroke. Diagnosis is by ECG showing no discrete P waves with irregular RR intervals, and management addresses rate or rhythm control, stroke prevention by CHA2DS2-VASc-guided anticoagulation, and the underlying cause.
- Wolff-Parkinson-White (WPW) syndrome
Wolff-Parkinson-White syndrome is ventricular pre-excitation via an accessory pathway plus symptomatic tachyarrhythmia, marked on the resting ECG by a short PR interval and a delta wave. Its danger is pre-excited atrial fibrillation, which can conduct rapidly to the ventricles and degenerate into ventricular fibrillation; AV nodal blockers are contraindicated in that setting, and catheter ablation of the pathway is curative.