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.
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What this article covers
- Overview
Definition: supraventricular tachycardia (SVT) is any tachyarrhythmia originating at or above the AV node, encompassing AV nodal reentrant tachycardia, AV reentrant tachycardia, atrial tachycardia…
- Epidemiology
Common, often first presenting in young, otherwise healthy adults.
- Risk factors
Reentry substrate: dual AV nodal physiology or an accessory pathway.
- Pathophysiology
Reentry: a self-sustaining circuit (within the AV node for AVNRT, or using an accessory pathway for AVRT) drives most regular SVT.
- Clinical features
Abrupt palpitations with a rapid regular pulse.
- Differential diagnosis
AV nodal reentrant tachycardia: the most common regular narrow-complex SVT (paroxysmal supraventricular tachycardia).
- Diagnosis
Establish with an ECG showing a regular narrow-complex tachycardia and define the mechanism by the P-wave relationship and response to AV nodal blockade: the diagnostic basis is a 12-lead ECG (in…
- Management
First-line, treat instability immediately: synchronized cardioversion for any unstable tachyarrhythmia (hypotension, ischemia, altered mentation).
- Complications
Recurrent symptomatic episodes. Hemodynamic compromise or syncope at very rapid rates or with structural disease.
- Prognosis
Excellent for the common reentrant SVTs, curable by ablation.
- Prevention
Avoid triggers: caffeine, alcohol, and stimulants.
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Related articles
- 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.
- 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.
- Atrial flutter
Atrial flutter is a macro-reentrant atrial tachyarrhythmia, typically a right atrial cavotricuspid isthmus circuit, producing sawtooth flutter waves at about 300 per minute with a regular ventricular response (often 2:1, giving a rate near 150). It carries the same stroke risk as atrial fibrillation, and cavotricuspid isthmus ablation is highly effective and curative for typical flutter.
- 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.
- Multifocal atrial tachycardia
Multifocal atrial tachycardia is an irregular atrial tachyarrhythmia defined by at least three distinct P-wave morphologies and varying PR intervals, arising from multiple atrial foci and strongly associated with severe pulmonary disease such as COPD exacerbation. Diagnosis is by ECG, and treatment centers on correcting the underlying illness, with a non-dihydropyridine calcium channel blocker for rate control.
- Sinus tachycardia
Sinus tachycardia is a sinus rhythm above 100 per minute, almost always a physiologic response to an underlying stressor such as fever, hypovolemia, pain, anemia, hypoxia, or hyperthyroidism. Management targets the cause rather than the rate, and rate-slowing drugs are usually harmful when tachycardia is compensatory.