Page 22 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

Chapter 1
to be associated with conversion of AF, further demonstrating that such lesions may at least in some patients deeply modify the substrate of AF118-119. Based on previous experience by Pappone et al112 four major left atrial ganglionated plexi have recently been identified in patients with AF. Plexi may be localized at the time of ablation using high-frequency stimulation delivered by a mapping catheter in the LA. For ablation, RF current (20-35W) can be applied at each site of positive vagal response to high-frequency stimulation. Pachon et al120 have developed a system for real-time spectral mapping that identifies sites in which the unfiltered, bipolar electrograms contain unusually high frequencies, namely fibrillar myocardium or the so-called AF nest.The investigators have successfully targeted biatrial AF nests, without intentional PV isolation, as a novel approach for AF.The adjunct of AF nest ablation has shown a favourable impact on long-term outcome following a single antral PV isolation115. Finally, a stepwise approach has recently been developed in patients with long-lasting persistent AF with different sequences that target multiple atrial areas121.
New ablation technologies are currently under intense investigation. Balloon- based ablation systems have been developed to create circular lesions around PVs at the atrial level. Furthermore, new software algorithms have been developed to support the various methods of image integration (from MR or CT) and to further improve the image registration process. Finally, real-time catheter-based imaging systems for on-line 3-D cardiac chamber reconstruction based on ICE technology are under investigation.
The absence of new antiarrhythmics with an improved benefit/risk profile as well as the results of several recently published clinical trials demonstrating superior outcomes with catheter ablation for AF relative to antiarrhythmic drug therapy122-124 suggest that AF ablation may warrant consideration as first-line therapy in selected patients125.
Indeed some authors126 believe that first-line should at least be considered for those patients with symptomatic AF, mild to moderate structural heart disease and paroxysmal or persistent AF. Ablation might particularly benefit younger patients with LAF who are frequently symptomatic and for whom very long term antiarrhythmics and anticoagulation pose higher risks and lifestyle costs. Asymptomatic or minimally symptomatic AF patients may also benefit from ablation and SR in the long term, but until further clinical data are available, it is difficult to justify an invasive procedure to patients who may not be aware that they have a problem.
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