Magnetic navigation in AV nodal re-entrant tachycardia study: early results of ablation with one- and three-magnet catheters

Abstract

Aims Steering soft, flexible catheters using an external magnetic field could have advantages for heart catheterization, especially for therapy of tachyarrhythmias. Our aims were to assess the feasibility of magnetic navigation to Koch's triangle and reliable ablation of atrioventricular nodal re-entry tachycardia (AVNRT) with a magnetic catheter. Methods and results Consecutive patients with AVNRT were mapped and ablated with a magnetically enabled catheter (Helios I or II), with, respectively, one and three magnets at the tip. The catheter was remotely advanced with the Cardiodrive TM system and orientated with the Navigant TM control system. After initial positioning with the external magnets, adjustment was made in 58 steps. Success rates, procedure, and fluoroscopy times were analysed, and compared with a local contemporary series of conventional AVNRT ablations. Magnetic navigation was feasible in all 20 patients. Targets were easily reached. Catheters remained stable in position during accelerated junctional rhythms. Ablation was successful in 18/20 procedures (90%). No significant complications occurred. Median patient fluoroscopy time was 12 min, median physician fluoroscopy time was 4 min. Fluoroscopy times tended to be shorter than that in the conventionally treated group. Procedure duration decreased significantly over time, median procedure time was similar to that in the conventional group. Conclusion AVNRT can be successfully mapped and ablated using magnetic navigation. A learning curve was evident, unrelated to catheter type, but to increasing operator experience. Physician radiation times were one-third of patient times. No complications occurred. Procedure time is comparable with that of conventional ablation.

An in vivo comparison of radiofrequency cardiac lesions formed by standard and magnetically steered 4 mm tip catheters

“…7,[10][11][12][13][14][15][16] Comparison of standard vs. magnetic catheters Ablation lesions formed by magnetically steered catheters have similar characteristics to those from standard catheters. The only significant differences appear to be that the lesions from magnetically steered catheters are more round or oval rather than elongated, suggesting more constant catheter tissue contact.…”

“…7 The Niobe I magnetic navigation system (Stereotaxis Inc.), with a combined field strength of 0.08 Tesla, was combined with a monoplane angiography system (AXIOM Artis, Siemens, Erlangen, Germany). The magnets and generated field were controlled via a workstation (Navigant, Stereotaxis Inc.) to allow for changes in the direction of a stable magnetic field within the heart of the patient.…”

Remote Magnetic Navigation for Catheter Ablation in Patients With Congenital Heart Disease: A Review

“…[26][27][28][29][32][33][34][35][36][37][38][39][40][41] It also has safety advantages with a lower risk of cardiac perforation due to the compliant nature of catheter and lower fluoroscopy exposure. Moreover, in patients with distorted anatomy or extensively dilated cardiac chamber, due to the magnetic ablation catheter being steered via the distal tip, it facilitates reaching all areas, thereby increasing sequential 3D 46 Wu et al 47 Wu et al 48 Akca et al 17 Ernst et al 15 Ueda et al †16 Horduna et al 49 Roy et al 50 Number of patients Wu et al 47 Wu et al 48 Akca et al 17 Ernst et al 15 Ueda et al †16 Horduna et al 49 Roy et al 50 7 ablation with RMT catheter (3 with 4 mm and 4 with 8 mm)…”

Remote Navigation for Complex Arrhythmia

“…16 Moreover, the median physician radiation exposure time was three-times lower than the patient exposure time. 15 No significant complications occurred. One transitory AV block reported in the magnetic group fully recovered.…”

“…24,25,28 Atrioventricular Nodal Re-entrant Tachycardia Previous studies have emphasised the efficacy and safety of the technique in treating more discrete substrates such as slow pathway ablation/modulation for atrioventricular (AV) re-entrant tachycardia. 15,16 When direct comparison was made between RMN ablation and conventional approach, magnetic guidance seemed similar, if not superior, in terms of efficacy compared with conventional catheter ablation of AVNRT. Previous studies reported comparable results when conventional techniques were used.…”