AV reentrant tachycardia
Editor-In-Chief: C. Michael Gibson, M.S., M.D. ; Associate Editor(s)-In-Chief: Varun Kumar, M.B.B.S. 
Synonyms and keywords: AVRT; AV-reciprocating tachycardia; atrioventricular reentrant tachycardia; circus movement tachycardia
AVRT results from an anatomically distinct atrioventricular connection. The causes, which usually are congenital or genetic, include: Ebstein anomaly, Lown-Ganong-Levine syndrome, Mahaim fiber tachycardia, Wolff-Parkinson-White syndrome.
Two types of tachycardia fall under this category:
Orthodromic Atrioventricular Reentrant Tachycardia
In orthodromic AVRT, the antegrade conduction (from the atria to the ventricles) occurs through the AV node, whereas the retrograde conduction (from the ventricle to the atrium) occurs through the accessory pathway. In this case, the ECG will reveal narrow QRS and retrograde P wave following the QRS complex.
Antidromic Atrioventricular Reentrant Tachycardia
In antidromic AVRT, the antegrade conduction (from the atrium to the ventricle) occurs through the accessory pathway, whereas the retrograde conduction (from the ventricles to the atria) occurs through the AV node. In this case, the ECG will reveal wide QRS similar to those found in ventricular tachycardia.
Life Threatening Causes
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.
AV nodal reentrant tachycardia is usually not life-threatening.
Causes by Organ Systems
|Cardiovascular||Ebstein anomaly, Lown-Ganong-Levine syndrome, Mahaim fiber tachycardia, Wolff-Parkinson-White syndrome|
|Chemical/Poisoning||No underlying causes|
|Dental||No underlying causes|
|Dermatologic||No underlying causes|
|Drug Side Effect||No underlying causes|
|Ear Nose Throat||No underlying causes|
|Endocrine||No underlying causes|
|Environmental||No underlying causes|
|Gastroenterologic||No underlying causes|
|Hematologic||No underlying causes|
|Iatrogenic||No underlying causes|
|Infectious Disease||No underlying causes|
|Musculoskeletal/Orthopedic||No underlying causes|
|Neurologic||No underlying causes|
|Nutritional/Metabolic||No underlying causes|
|Obstetric/Gynecologic||No underlying causes|
|Oncologic||No underlying causes|
|Ophthalmologic||No underlying causes|
|Overdose/Toxicity||No underlying causes|
|Psychiatric||No underlying causes|
|Pulmonary||No underlying causes|
|Renal/Electrolyte||No underlying causes|
|Rheumatology/Immunology/Allergy||No underlying causes|
|Sexual||No underlying causes|
|Trauma||No underlying causes|
|Urologic||No underlying causes|
|Miscellaneous||No underlying causes|
Causes in Alphabetical Order
Electrical activity of the heart is rerouted through an accessory pathway that connects the atria with the ventricles.
The appearance of QRS alternans as part of a narrow complex tachycardia suggests the diagnosis of orthodromic atrioventricular (AV) reentrant tachycardia which conducts retrograde over an accessory pathway.
Below is a video explaining the mechanism of AV re-entrant tachycardia
Wolff-Parkinson-White syndrome Lown-Ganong-Levine syndrome