Atrioventricular Tachycardia

Atrioventricular node reentrant tachycardia

Other than atrial fibrillation and atrial flutter, this is the most common supraventricular tachycardia seen in practice.11 A large minority of adults (up to 40% in some cohorts) are born with 2 pathways that can conduct electricity in the AV node, rather than 1. Under the right conditions, AV node reentrant tachycardia (AVNRT) can be initiated by a premature atrial or ventricular beat. If the 2 pathways are able to sustain a stable circuit, the atrium and the ventricle are depolarized almost simultaneously. As a result, on the ECG, the P wave is not seen, is buried in the QRS complex, or is seen at the terminal portion of the QRS, typically as a pseudo-s (negative) wave in the inferior leads or a pseudo-r0 in lead V1. Because this tachyarrhythmia depends on the AV node, both vagal maneuvers and adenosine are potential acute treatment options. In the outpatient setting, if the patient is in a sustained supraventricular tachycardia, attempting vagal maneuvers is reasonable. These maneuvers should include bearing down,

The ECG in this setting should have a typical right or left bundle branch block appearance. A typical example of this tachyarrhythmia is atrial flutter with 1:1 AV conduction.

Supraventricular tachycardia with atrioventricular conduction via an accessory pathway This entity is only (and rarely) seen in patients with Wolff-Parkinson-White syndrome. It involves conduction of the atrial signal antegrade down the accessory pathway and retrograde up the AV node. Because ventricular depolarization occurs cell to cell, rather than via the normal conduction system, the QRS is wide and mimics monomorphic ventricular tachycardia. This tachycardia is also known as antidromic AVRT.1 A prior ECG with a delta wave typical of Wolff-Parkinson-White syndrome is helpful for this