Twitching of the Pacemaker Pocket Induced by Radiofrequency Energy Delivery to the Cavotricuspid Isthmus.

An 82-year-old man with a permanent pacemaker (PM) implanted for sick sinus syndrome complained of palpitation due to paroxysmal atrial fibrillation and flutter. During extensive pulmonary vein isolation, the atrial lead was dislodged to the level of the tricuspid annulus. Radiofrequency energy delivery to the cavotricuspid isthmus reproducibly caused twitching of the PM pocket. The atrial lead was repositioned to the right atrial appendage, PM check revealed no functional change in the PM or lead performance. This is the first reported case of twitching of the PM pocket due to electromagnetic interference.