“Sequential” Mapping Mimicking “Simultaneous” Mapping Using Magnetic Navigation During Catheter Ablation of Supraventricular Tachycardia: Results of the Single DX Study

Introduction: The magnetic navigation system (MNS) allows remote‐controlled navigation of an ablation catheter from the control room. We tested the hypothesis, whether the MNS and a single additional diagnostic nonsteerable catheter would have the potential to identify the tachycardia substrate and allow subsequent ablation in patients with documented supraventricular tachycardia (SVT). Methods and Results: A total of 41 patients (24 females, age 45 ± 16 years) underwent an invasive electrophysiologic (EP) study using the MNS. Together with a conventional diagnostic catheter in the right ventricle, the magnetic catheter (MC) was used to investigate the underlying EP substrate in a sequential fashion and subsequently to perform radiofrequency (RF) ablation. A custom‐made device allowed the separate assessment of fluoroscopy deployed from the control and examination room. Using conventional EP criteria, identification of the underlying substrate was possible in all but 4 noninducible patients (no accessory pathway [AP], no dual atrioventricular [AV] node): APs were present in 10 patients, AV node re‐entrant tachycardia in 26 patients, and ectopic atrial tachycardia in 1 patient. Despite 3 patients, in which switching to conventional ablation was necessary (8%), all others were successfully treated using the MNS. Overall fluoroscopy amounted to a median of 3.4 minutes (interquartile range, 2.4–5.3) with only a median of 1.0 minute exposure for the investigator. Conclusions: Remote catheter ablation of SVT using the new MNS Niobe and a single conventional diagnostic catheter is feasible. Compared to conventional EP studies, a reduction of radiation exposure for both patients and investigators was demonstrated.