Transient conduction disturbance during pulsed-field ablation for atrial fibrillation in a patient with pre-existing conduction disease.

Pulsed-field ablation (PFA) is a novel, non-thermal technique for atrial fibrillation (AF) ablation, known for its tissue specificity and reduced risk of collateral damage. However, its impact on cardiac conduction pathways in patients with pre-existing conduction abnormalities is not well understood. We present the first documented case of transient conduction block observed during PFA for AF. A late 60s male with paroxysmal AF and a dual chamber pacemaker for sinus node disease underwent successful PFA using a 31 mm pentaspline FARAPULSE catheter. During pulmonary vein isolations, transient prolongation of atrioventricular conduction time and a temporary shift from right bundle branch block to left bundle branch block lasting up to four beats were observed. This novel observation underscores the need for careful monitoring of conduction during PFA, particularly in patients with underlying conduction disorders, and highlights the importance of further research into PFA's mechanism of action and its long-term impact.