Catheter Ablation of Accessory Pathway in the Treatment of Pacemaker‐Mediated Tachycardia

Abstract

Pacemaker-mediated tachycardia (PMT) remains a clinical problem in patients with dual-chamber pacemaker despite technological advances. The onset mechanism of this tachycardia is sensing of retrograde atrial activation after ventricular stimulation. Repeated retrograde conduction perpetuates tachycardia. Postventricular atrial refractory period prolongation has been used for prevention of PMT, but this is not the solution in all cases. We present a case with PMT where the retrograde limb is a left accessory pathway, which is treated with radiofrequency ablation successfully.

Treatment of atypical pacemaker‐mediated tachycardia with ablation of the retrograde atrioventricular nodal pathway

“…Ablation of retrograde conduction for refractory PMT was first reported by Pitney using DC shock 7 . In patients with complete heart block, Larsen and Ellenbogen 4 reported ablation of the retrograde slow pathway; Ducceschi et al 5 reported ablation of the retrograde fast pathway; and Robledo‐Nolasco et al 8 reported ablation of a concealed accessory pathway. Timmermans reported a patient who had 2:1 AV block after fast‐pathway ablation for AVNRT 3 ; ablation at the site of earliest VA conduction near the coronary sinus orifice caused complete AV and VA block.…”

Pacemaker‐mediated arrhythmias

“…3 In this arrhythmia, VA conduction works as the retrograde limb and consequent atrial tracking by the pacemaker as the antegrade ----------------------------------------------------------------------------------------------------------------------------------------------------------------------limb of the macro-reentrant circuit. 1,4 Therefore, during this arrhythmia, an atrial sensing-ventricular pacing sequence will be observed.…”

“…In this arrhythmia, VA conduction works as the retrograde limb and consequent atrial tracking by the pacemaker as the antegrade limb of the macro‐reentrant circuit . Therefore, during this arrhythmia, an atrial sensing‐ventricular pacing sequence will be observed.…”