Slow Pathway Radiofrequency Ablation Using Magnetic Navigation: A Description of Technique and Retrospective Case Analysis.
BACKGROUND
The Magnetic Navigation System (MNS) catheter was shown to be stable in the presence of significant cardiac wall motion and delivered more effective lesions compared to manual control. This stability could potentially make AV junctional re-entrant tachycardia (AVNRT) ablation safer. The aim of this study is to describe the method of mapping and ablation of AVNRT with MNS and 3-D electro-anatomical mapping system (CARTO, Biosense Webster, Diamond bar, CA, USA) anatomical mapping, with a view to improve the safety of ablation.


METHODS
The method of precise mapping and ablation with MNS is described. Consecutive AVNRT cases (n=30) from 2012 January to 2015 November, in which magnetic navigation was used, are analysed.


RESULTS
Ablation was successful in 27 (90%) out of 30 patients. In three cases, ablation was abandoned due to the proximity of the three-dimensional His image to the potential ablation site. No complications, including AV nodal injury, occurred. The distance from the nearest His position to successful ablation site in both LAO and RAO projections of CARTO images was 26.4±8.8 and 27±7.7mm respectively. Only in two (9%) patients, ablation needed to be extended superior to the plane of coronary sinus ostium, towards the His bundle region, to achieve slow pathway modification.


CONCLUSIONS
AVNRT ablation with MNS allows for accurate mapping of the AV node and stable ablation at a safe distance, which could help avoid AV nodal injury. We recommend this modality for younger patients with AVNRT.
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Abhishek
A
Bhaskaran
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Maha
M
Albarri
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia.
Neil
N
Ross
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Sara
S
Al Raisi
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Rahul
R
Samanta
Johnson & Johnson Inc., Sydney, NSW, Australia.
Leonette
L
Roode
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Fazlur
F
Nadri
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Jeanette
J
Ng
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Stuart
S
Thomas
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
Aravinda
A
Thiagalingam
Cardiology Department, Westmead Hospital, Sydney, NSW, Australia; Sydney Medical School, University of Sydney, Sydney, NSW, Australia. Electronic address: pramesh.kovoor@sydney.edu.au.
Pramesh
P
Kovoor
D000328:Adult; D017115:Catheter Ablation / Q000379:methods*; D054326:Coronary Sinus; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008280:Magnetics / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome
AV junctional re-entrant tachycardia; AV node injury; Efficacy; Magnetic navigation; Radiofrequency ablation; Safety