Details of adverse effects of AF ablation on CIEDs
In this study, no permanent pulse generator malfunctions and no dislodgement of leads were observed. However, lead failure was observed in 3 of 34 patients, with a sensing noise in 1 patient and a significant impedance increase in 2 patients after SVCI. A 67-year-old man showed sensing noises 2 months after the second SVCI. He had undergone implantation of a dual chamber pacemaker 16 years before the first AF ablation. No sensing noises were observed after the first SVCI. The second session of the AF ablation was performed 14 months after the first session. Electrical isolation of the SVC was successfully achieved through RF application (maximum power, 25 W) to the lateral wall of the SVC contiguous to the leads using a 3.5-mm open-irrigated tipped catheter without contact force-sensing technology (Navistar ThermoCool SF, Biosense Webster, Inc., Diamond Bar, CA). Thereafter, sensing noise on an atrial pacing lead was observed. The diameter of the lead body (Stelid BJ45D, ELA Medical, Montrouge, France) was 2.5 mm, and its outer insulation material was silicone. Two patients showed an increase in lead impedance. One was an impedance increase of the ventricular lead (389–795 ohms) implanted 10 years before the ablation. The diameter of the ventricular lead (Thinline Ⅱ Sterox EZ, Intermedics, TX, USA) was 1.7 mm, and its outer insulation material was polyurethane. The other was an impedance increase of the atrial pacing lead (456–779 ohms) implanted 4 years before the ablation. The diameter of the atrial lead (CapSure Fix Novus, Medtronic, MN, USA) was 2 mm, and its outer insulation was silicone. Both leads functioned normally; therefore, an additional procedure such as lead exchange was not required.

Discussion

This study investigated whether leads in the SVC might become obstacles in achieving electrical isolation of the SVC and whether RF application during SVCI might damage the leads. The main findings of this study were as follows: (i) SVCI was successfully achieved in 91.2% of the study patients after the final ablation procedure, (ii) lead parameters did not significantly differ after SVCI; however, (iii) 3 lead failures (8.8% of the study patients) were observed after SVCI.