Atrial Substrate Modification for Atrial Fibrillation
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See Article by Yang et al
Catheter ablation is increasingly recommended for the management of all forms of atrial fibrillation. Rates of freedom from atrial fibrillation have remained suboptimal, however, and the search for the best procedural strategy remains an active area of research. Elimination of pulmonary vein triggers by circumferential pulmonary vein isolation (CPVI) is an integral part of any catheter-based ablation procedure for atrial fibrillation. Ablation beyond CPVI is more problematic. Multiple lesion patterns have been proposed, usually with some evidence of benefit, but at this point, operators need to be cognizant of the risks and benefits associated with them, as well as the relative paucity of comparative data between approaches. Disadvantages of extensive left atrial ablation include
Linear ablation aimed at compartmentalizing the left atrium is fraught with inability to achieve a durable and complete line connecting 2 electrically inactive anatomic or electrophysiological landmarks. Incomplete lines provide iatrogenic milieu for macro-reentrant tachycardia.1,2
Collateral damage of the surrounding organs, most significantly the esophagus, always provides a rationale for limiting the amount of tissue ablated.
More extensive ablation increases the chance of complications, including thromboembolism and bleeding. Moreover, extensive ablation of atrial tissue may lead to compromised atrial function.
The clinical decision to proceed with additional ablation beyond CPVI is driven by multiple factors. The chronicity of persistent atrial fibrillation, a high left atrial volume, and the presence of scar assessed either by magnetic resonance imaging or intraprocedural voltage mapping certainly increases the likelihood of extrapulmonary vein ablation. A common clinical practice has been to perform a stepwise ablation procedure in which initial wide area pulmonary vein isolation is followed by additional linear ablation lesions or focal ablation guided by complex fractionated atrial electrograms, ganglionated plexuses or rotors to achieve either termination of atrial fibrillation, organization …