Atrioventricular reentrant tachycardia (AVRT), or atrioventricular reciprocating tachycardia, is a type of

heart arrhythmia Arrhythmias, also known as cardiac arrhythmias, are irregularities in the cardiac cycle, heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – ab ...

with an abnormally fast rhythm (

tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...

); it is classified as a type of

supraventricular tachycardia Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms – ventricular tachycardia, which start within the lower cham ...

(SVT). AVRT is most commonly associated with

Wolff–Parkinson–White syndrome Wolff–Parkinson–White syndrome (WPWS) is a disorder due to a specific type of problem with the electrical system of the heart involving an accessory pathway able to conduct electrical current between the atria and the ventricles, thus byp ...

, but is also seen in permanent junctional reciprocating tachycardia (PJRT). In AVRT, an

accessory pathway In cardiology, an accessory pathway is an additional electrical connection between two parts of the heart. These pathways can lead to abnormal heart rhythms ( arrhythmias) associated with symptoms of palpitations. Some pathways may activate a regi ...

allows electrical signals from the heart's ventricles to enter the

atria Atria may refer to: Science *Atrium (heart) (plural: atria), an anatomical structure of the heart *Atria (genus), a flatworm genus in the family Dendrocoelidae * Atria (star) or Alpha Trianguli Australis, a star in the constellation Triangulum Aus ...

and cause earlier than normal contraction, which leads to repeated stimulation of the

atrioventricular node The atrioventricular node (AV node, or Aschoff-Tawara 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 ...

.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 occur when a person becomes aware of their heartbeat. The heartbeat may feel hard, fast, or uneven in their chest. Symptoms include a very fast or irregular heartbeat. Palpitations are a sensory symptom. They are often described as ...

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

shortness of breath Shortness of breath (SOB), 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 discomfort that con ...

, 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

.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 (AV node, or Aschoff-Tawara 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 ...

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 build ...

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 ( arrhythmia), and to protect the heart from a second heart attack after a first heart attack ( secondary prevention ...

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, sensory nerves or a dysfunctional tissue is ablated using the heat generated from medium fre ...

of the accessory pathway.

References

External links

{{Circulatory system pathology Cardiac arrhythmia

Signs and symptoms

Pathophysiology

Treatment

See also

References

External links