Author + information
- David J. Callans, MD, FACC⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. David J. Callans, Section of Cardiac Electrophysiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104.
The future offers very little hope for those who expect that our new mechanical slaves will offer us a world in which we may rest from thinking.
Norbert Wiener (1)
After the initial frenetic excitement over seminal observations leading to our ability to treat atrial fibrillation (AF) with catheter ablation, we have reached a plateau, marked by little momentum in the fight against this adversary. Although the procedure is getting progressively safer (2), there are little but exaggerated claims to suggest significant improvement in efficacy, particularly in patients with more established AF. There is a general sense that the next breakthrough is eminent, but it is unclear whether it will be supplied by a better understanding of the underlying pathophysiology leading to new ablation strategies or by improvements in technology leading to more effective ways of performing the present procedure.
The study by Saliba et al. (3) in this issue of the Journal may provide some insight into the feasibility of a technology that may prove helpful. They present a multicenter experience with ablation of atrial fibrillation and atrial flutter using a robotic steerable guiding sheath (Artisan Control Catheter, Sensei Robotic System, Hansen Medical, Mountain View, California). This system uses a master-slave electromechanical system to direct a 14-F steerable sheath to guide and potentially stabilize the ablation catheter. Pulmonary vein antral isolation was performed in 40 patients with drug-refractory AF (30 paroxysmal, 10 “recently persistent”); in addition, isthmus-dependent atrial flutter was also ablated in 23 patients. After the first transseptal puncture, all other elements of the procedure (the second transseptal puncture, pulmonary vein and superior vena cava isolation, isthmus ablation) were performed with use of the robotic system. Procedures were also guided by intracardiac echocardiography and electroanatomic mapping; the data from these modalities are also imported for online assessment on the physician workstation. Ablation was performed with an externally irrigated catheter. The study was designed to assess the following end points: acute success (pulmonary vein and superior vena cava isolation, bidirectional isthmus block), procedural safety, and recurrence of atrial arrhythmias without use of antiarrhythmic drugs at 12 months.
The mean procedural and fluoroscopy times were reported to be 163 ± 88 min and 64 ± 33 min, respectively. This result is a little misleading, because AF and flutter ablations were counted as separate procedures. The procedural and fluoroscopic times for AF procedures specifically were 189 ± 88 min and 83 ± 15 min, respectively. All acute procedural end points were achieved with the use of robotic navigation. There were few procedural complications: cardiac perforation leading to tamponade was observed in 2 patients (1 perforation related to the initial, non-robotic transseptal procedure, 1 apparently caused by ablation [50 W] using the system). At 12 months after a single procedure, 34 patients were free from the symptomatic recurrence of atrial arrhythmias from the use of antiarrhythmic drugs, and an additional 5 patients were free from symptomatic arrhythmias who were using previously ineffective antiarrhythmic drugs. The authors concluded that the robotic system is feasible and safe and that despite the high incidence of tamponade, “there does not appear to be any increased risk of perforation or intracardiac damage associated with this...system.” Furthermore, because of the physical separation of the Sensei control system and the fluoroscopy unit, the operator's radiation exposure was dramatically reduced.
The authors should be congratulated for this initial effort. I agree that the feasibility and safety of the system has been demonstrated, although there are some lingering concerns. Despite the outstanding caliber and experience of the investigators, there was a high incidence of perforation in the experience, although only 1 perforation in 39 procedures using the system was noted. This complication is potentially instructive, regardless of whether the cause was actually an overpowered ablation lesion or excessive force delivered to the atrial wall. Robotic control has the potential to completely change the way that radiofrequency energy is delivered (see herein). The contact force issue may eventually be solved by a contact sensor, which is available in current models but not during the period of the study. The efficacy reported in this experience is phenomenal, and although not really the focus of this investigation, it underscores the vital need for more uniform post-procedural monitoring and reporting of results as called for by recent consensus documents (4,5).
More interesting is the potential promise of this technology, which this study was not designed to investigate. As the authors state, one of the major limitations of manual catheter manipulation is tissue contact. It is well documented that irrigated radiofrequency delivery in normal tissue in vitro results in very large lesions (6). It would follow that robotic technology that would enhance catheter contact would ensure extensive lesion creation, maybe even to a dangerous degree until we readjust dosing strategies. Whether the actual parameter that is important is catheter force (potentially adjustable with the Hansen system) or contact (which may be optimized with the Stereotaxis system) is not completely clear and may be of more than passing consequence in the battle between competing technologies.
The introduction of robotic technologies is, of course, not unique to electrophysiology. In the surgery arena, robotic procedures allow intuitive multidimensional complex movements of instruments in places in which incisions are too small to admit the human hand. Most electrophysiologists value intellectual and integrative skills more than the technical. In any case, it is not clear that more dexterity is needed during AF ablation; the potential benefit really depends on whether improved catheter stability provides more efficient and consistent energy delivery. The implementation of robotic systems in surgery has provided some excitement and a fair amount of skepticism. In a general review, it was concluded that despite significant promise, “Up to this point, the race to acquire and incorporate this emerging technology has primarily been driven by the market” (7). Even in the relatively well-established application for prostatectomy, although observational series suggest a reduction in both blood loss and surgical complications such as erectile dysfunction and incontinence, “no randomized trials have been published that have compared traditional treatment with minimally invasive treatments” (8).
I really hope that the question posed in the title of this editorial is “yes.” However, at the risk of being called a Luddite, advanced technologies in general will only be implemented if they add value to balance their considerable cost. This value needs to be measurable in terms of improving efficacy of routine procedures, allowing us to do complex procedures that would be otherwise impossible, or improving laboratory efficiency and safety. Eventually, the authors of carefully designed studies will evaluate whether real value is added by incremental technology; these studies should be performed after the centers involved have mastered use of the technology, to prevent bias. This observational study by Saliba et al. (2) provides a starting point for hypothesis driven trials to establish the real value of this technology.
↵⁎ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
- American College of Cardiology Foundation
- ↵Wiener R. God and Golem Inc.; a Comment on Certain Points Where Cybernetics Impinges on Religion. Cambridge, MA: M.I.T. Press, 1964.
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