What is needed for a good 'Decaf'?

Abstract

Catheter-based pulmonary vein (PV) isolation is associated with good clinical outcomes in patients with recurrent atrial fibrillation (AF) and moderate heart disease. 1,2 Limited efficacy of PV isolation in patients with structural heart disease and persistent AF might be explained by non-PV-mediated AF or a predominance of a critical substrate maintaining AF. This substrate for AF—thought to consist of focal drivers/rotors, multiple wavelet re-entry, or a three-dimensional labyrinth of narrow waves showing discontinuous lateral conduction—is expected to show considerable interindividual variation. 3 In order to optimize ablation outcomes in these patients, one could advocate either a uniform, anatomybased ablation strategy with predefined linear lesions or an electrogram-based ablation approach guided by individual diagnosis of the critical arrhythmogenic substrate. This latter patient-specific strategy has been shown to be highly effective in many atrial and ventricular tachyarrhythmias with reported success rates up to 95%. Interestingly, in most of these cases, fractionated electrograms identify the critical substrate and as such the ablation target of the corresponding arrhythmia. 4 Likewise, complex fractionated atrial electrograms (CFAEs) during AF have been proposed as the electrocardiographic representation of the ‘critical fibrillatory substrate’. Konings et al. 5 demonstrated that fractionation of extracellular unipolar electrograms during AF is caused by various types of conduction disturbances such as collision, block, pivot points, or slow conduction, all essential for the maintenance of AF. Other studies demonstrated that fractionated fibrillatory electrograms might be recorded in the vicinity of focal AF sources or ganglionated plexi. 6,7 Ablation targeting exclusively complex fractionated electrograms (defractionation or ‘de-CFAE’) was reported to be associated with a high success rate in persistent and permanent AF. 8