Safety of Remote Magnetic Navigation in Patients With Pacemakers and Implanted Cardioverter Defibrillators

BACKGROUND: Remote magnetic catheter navigation (MNS) has been shown to be feasible and safe for radiofrequency catheter ablation of various cardiac arrhythmias. However, its safety in patients with implanted pacemakers or cardioverter-defibrillators has not yet been studied. OBJECTIVES: This retrospective case series study intends to assess the acute and short-term safety of remote MNS in patients with implanted pacemakers or cardioverter-defibrillators. METHODS: Between January 2008 and June 2009, a total of 31 patients with implanted pacemakers (n = 5) or cardioverter-defibrillators (n = 26) underwent 32 catheter ablation procedures using the remote MNS. Baseline pacing thresholds, sensed amplitudes, pacing and, if available, shock impedances as well as battery status were measured in all devices before, immediately after, and 1-3 months after catheter ablation. RESULTS: After ablation, no statistically significant difference in atrial sensing (2.7 ± 1.5 mV vs 3.1 ± 1.9 mV, P = 0.18) and impedance (457 ± 104 Ω vs 449 ± 101 Ω, P = 0.37) were observed. After ablation, no statistically significant difference in right ventricular sensing (10.4 ± 3.8 mV vs 10.9 ± 4.9 mV, P = 0.43) and impedance (535 ± 118 Ω vs 534 ± 120 Ω, P = 0.913) were observed. No changes in pacing threshold could be observed in all but 2 patients with biventricular cardioverter-defibrillators who underwent ventricular tachycardia ablation in lateral wall of left ventricle near the implanted epicardial electrode. CONCLUSIONS: Ablation procedures using remote MNS can be performed safely in patients with implanted devices with no significant effects on device system integrity. Long endocardial ablation close to the insertion site of the implanted epicardial left ventricular leads can affect the pacing and/or sensing characteristics of these electrodes.