Remote magnetic navigation for atrial fibrillation ablation: is ‘As Good as Manual’ good enough

This editorial refers to ‘Catheter ablation of atrial fibrillation using remote magnetic catheter navigation: a case–control study’ by A. Arya et al., on page 45

Remote magnetic navigation for arrhythmia procedures has been performed since 2004. It has been shown to be useful in a variety of ablation procedures such as supraventricular tachycardia, ventricular tachycardia, epicardial ablation, and atrial fibrillation.^1–5 The navigation technology is remarkable in that it has the ability to magnetically direct the tip of a floppy catheter, allowing the system to perform procedures that are difficult for some operators with manual navigation catheters. The system has also brought the ability to perform automated navigation and ablation to a specialty dominated by hands-on procedures. One of the most difficult challenges of the new technology is performing the same procedures safely. Remote magnetic navigation has demonstrated a fantastic safety record, including in the paper published by Arya et al.⁶

Unfortunately, all that glitters is not gold. One of the main limitations of the system has been the delay in modern ablation technology being available for use with the system. As the system requires the use of specialized catheters, currently available catheters cannot be used with the system without being modified. Of course, regulatory process adds significant additional time beyond development.

Although some of the previous publications on atrial fibrillation ablation report reasonable success rates,⁵ we reported the inability to achieve pulmonary vein isolation with the solid tipped catheters and dismal success rates. Also reported it was a very high incidence of charring on the catheter tip.⁷ At the time, open-irrigated tip radiofrequency ablation catheters had been available for years for use with manual ablation. The authors reported that the technology was capable, but limited by the available ablation technology. We have confirmed the ability to achieve isolation one hundred percent of the time with the open-irrigated magnetic catheter but long-term success data are not yet available.

Now that the open-irrigated magnetic ablation catheter is available, the reports of atrial fibrillation ablation experience are being presented.⁷ Arya et al. studied the outcome of ablation of atrial fibrillation, using remote magnetic navigation, in a large group of patients compared with a similar group who underwent manual ablation. The authors report similar success rates with markedly reduced fluoroscopy times. Also, complications appeared to be lower in the magnetic navigation group, but this was not statistically significant. The reductions in fluoroscopy time and low complication rates have been repeated by others. Unfortunately, compared with manual navigation, the procedure time and ablation time were significantly longer.⁶ This has also been seen in other publications.^7,8 Arya et al. reported that a significant portion of that time may have been performing other duties, which is one of the luxuries of remote magnetic navigation, but even when this is considered, the time is longer.⁶ The inability to achieve pulmonary vein isolation in all patients is also concerning.

This is the first time that remote magnetic ablation and manual ablation have been compared on a level playing field for atrial fibrillation ablation, although the study is not randomized. It appears that ablation using the magnetic system may be as effective as manual ablation with an excellent safety profile and lower radiation dose; although, this comes at the expense of longer procedure and ablation times. The safety aspect is best confirmed in randomized, controlled trials, but it does make sense that the magnetic system may reduce complications associated with high contact forces. The magnetic system has significantly lower maximal contact forces, but may have improved overall contact. As high contact forces are associated with steam pops, perforation, and possibly other complications, the safety advantage may be expected.⁹ Randomized, controlled trials should be performed to further assess the safety and efficacy of the system.

Certainly, magnetic navigation has proved to be an important technology. It shines in the treatment of ventricular arrhythmias³ and may provide navigation that is superior to manual navigation in this disorder. Unfortunately, atrial fibrillation ablation is more of a challenge for the system. Experienced ablationists seem to be able to perform the procedure faster and with at least comparable results, although it is conceivable that inexperienced operators may be able to perform the procedure faster and possibly more safely.

It is time for the magnetic navigation system to evolve into a magnetic therapy system. It is no longer acceptable to lag behind ablation technology for years. The system needs to be able to adapt to rapidly changing technologies, and perhaps develop its own technology. Considering that its style of navigation is significantly different from manual catheters, the possibilities for unique ablation devices suited to magnetic navigation are intriguing.

In the meantime, the system needs to significantly increase its speed and automation to surpass human abilities. In many other areas of technology, computerized control is far superior to techniques performed by humans. It is time for magnetic navigation and ablation to realize this potential. The system should be able to outperform the best of hands.

In the future, this type of technology could replace human hands for all arrhythmia therapies and extend to many other interventional therapies for cardiac and non-cardiac disease. This will require leadership in the industry and innovative development to achieve these goals.

Conflict of interest: J.D.B. is Consulting Chief Medical Officer, Stereotaxis. A.N. is an adisory board member for Stereotaxis. L.D.B. is a consultant for Biosense Webster and Hansen Medical.

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