In AVRT, an accessory pathway 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.

[1] An episode of SVT may present with palpitations, dizziness, shortness of breath, or losing consciousness (fainting).

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.

Then, the electrical impulse pathologically passes back into the atria via the accessory pathway, causing atrial contraction, and returns to the AV node to complete the reentrant circuit (see figure).

Long-term management includes beta blocker therapy and radiofrequency ablation of the accessory pathway.