Atrioventricular reentrant tachycardia (AVRT), or atrioventricular reciprocating tachycardia, is a type of abnormal fast heart rhythm and is classified as a type of supraventricular tachycardia (SVT). AVRT is most commonly associated with Wolff–Parkinson–White syndrome, but is also seen in permanent junctional reentrant tachycardia (PJRT). In AVRT, an

accessory pathway An accessory pathway is an additional electrical connection between two parts of the heart. These pathways can lead to abnormal heart rhythms or arrhythmias associated with symptoms of palpitations. Some pathways may activate a region of ventricula ...

allows electrical signals from the heart's ventricles to enter the atria and cause earlier than normal contraction, which leads to repeated stimulation of the

atrioventricular node The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of t ...

.Josephson ME. Preexcitation syndromes. In: Clinical Cardiac Electrophysiology, 4th, Lippincott Williams & Wilkins, Philadelphia 2008. p.339

Signs and symptoms

An episode of SVT may present with

palpitations Palpitations are perceived abnormalities of the heartbeat characterized by awareness of cardiac muscle contractions in the chest, which is further characterized by the hard, fast and/or irregular beatings of the heart. Symptoms include a rap ...

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

, or losing consciousness (fainting). The electrocardiogram (ECG) would appear as a narrow-complex SVT. Between episodes of tachycardia the affected person is likely to be asymptomatic; however, the ECG would demonstrate the classic delta wave in Wolff–Parkinson–White syndrome.Hampton J. The ECG Made Easy. Elsevier 2008

Pathophysiology

Two distinct pathways are involved: the normal atrioventricular conduction system, and an accessory pathway. During AVRT, the electrical signal passes in the normal manner from the

AV node The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of t ...

into the ventricles. Then, the electrical impulse pathologically passes back into the atria via the accessory pathway, causing atrial contraction, and returns to the

to complete the reentrant circuit (see figure). Once initiated, the cycle may continue causing the heart to beat faster than usual. Initiation of AVRT may be through a premature impulse of atrial, junctional, or ventricular origin.UpToDate: Atrioventricular reentrant tachycardia (AVRT) associated with an accessory pathway
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Treatment

Acute management is as for SVT in general. The aim is to interrupt the circuit. In the shocked patient, DC cardioversion may be necessary. In the absence of shock, inhibition at the AV node is attempted. This is achieved first by a trial of specific physical maneuvers such as holding a breath in or bearing down. If these maneuvers fail, using intravenous

adenosine Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9- glycosidic bond. Adenosine is one of the four nucleoside building ...

UK Resuscitation Council. Adult tachycardia algorithm. 2010.
/ref> causes complete electrical blockade at the AV node and interrupts the reentrant electrical circuit. Long-term management includes

beta blocker Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack ( secondary prevention). They are ...

therapy and

radiofrequency ablation Radiofrequency ablation (RFA), also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternati ...

of the accessory pathway.

References

External links

{{Circulatory system pathology Cardiac arrhythmia

Signs and symptoms

Pathophysiology

Treatment

See also

References

External links