Panel A and B . Intracardiac electrograms of young patient with a repeated procedure for a Mahaim fibre. The successful ablation was performed conventionally under fluoroscopy with 4 mm non-irrigated tip catheter, with applications between 8 and 9 o’clock on the tricuspid annulus. Panel A shows the tracings during antidromic atrioventricular re-entrant tachycardia (AVRT) with an atrial premature beat (APB) on His refractoriness (black star) from the HRA catheter (positioned at the lateral wall of the right atrium) which pre-excites the next ventricular activation with continuation of tachycardia. Panel B shows an antidromic AVRT initiation by a paced single atrial premature beat from high right atrium (black star) with the ablation catheter positioned in the His region. Notice the reversal of His activation sequence from proximal to distal activation in sinus rhythm (black big arrow) to distal to proximal His activation (small black arrows) at initiation and during antidromic AVRT.
Funding: this research has not received any funding or support in the means of grants, equipment or drugs.