Orthodromic AVRT due to a hidden accessory pathway

Patient

45-year-old man with no prior history, admittted for palpitations (several episodes over the past month lasting about 30 minutes);

Trace

This electrocardiogram performed between tachycardia episodes is within normal limits;

Trace

Recording of the onset of a tachycardia; an atrial extrasystole is conducted through the normal pathways with a prolonged PR interval; beginning of a tachycardia with narrow QRS and identical to the sinus complexes; atrial activity difficult to identify but seemingly present with 1:1 conduction in the ascending portion of the T wave; the positioning of atrial activity points to an orthodromic tachycardia due to accessory pathway;

Exergue

An accessory pathway is said to be hidden when there is no anterograde conduction; the occurrence of orthodromic tachycardia is possible if the conduction through the retrograde accessory pathway is preserved; there is however no risk of sudden death due to rapidly conducted atrial fibrillation. An accessory pathway is said to be hidden when there is no anterograde conduction; the occurrence of orthodromic tachycardia is possible if the conduction through the retrograde accessory pathway is preserved; there is however no risk of sudden death due to rapidly conducted atrial fibrillation.