Determination by termination: Use of termination of atrial fibrillation to determine comparability of methods to detect focal fibrillation sources
Termination of an arrhythmia by ablation based on intentional targeting of selection tissue is a powerful tool for validation of the targeting strategy.5 In the study by Alhusseini et al.,6 the authors used their own data from procedures in which FIRM‐guided ablation resulted in AF termination, and analyzed those recordings using a different method (that of Kuklik et al.7). With this, they found very good concordance of detection of focal AF sources (mainly rotors). Their criteria for a “match” were rather strict, and readers blinded to outcome agreed on mapped locations. Thus, termination of AF was used as a validating endpoint by which a determination could be made as to reproducibility of techniques of at least finding focal sources (albeit with a slightly different analytical algorithm).
Determining reproducibility of FIRM results will of course take more than the present study by Alhusseini and colleagues, or others using the same technology at multiple centers; necessary randomized trials are already in progress. Electrophysiology has seen new techniques to generate considerable enthusiasm based on initial reports, only to falter when others are unable to replicate the initial results. Examples include ablation of complex fractionated atrial electrograms (“CAFEs”) and ganglionated plexi. Each of these has good conceptual underpinnings as well as reasonable bodies of data supporting their clinical application. However, since many other investigators failed to replicate the initial encouraging results, these earlier techniques have been rarely used. The question always arises, however: are those who are trying to replicate the initial results really using the same techniques as the original investigators? CAFEs, and to an extent, identification of sites of ganglionated plexi and their ablation, are at least somewhat subjective and if electrophysiologists who wished to replicate initial results did not use the same techniques the original investigators did, why should the same results be expected? As a trivial example, I remember the first few cases of pulmonary vein (PV) isolation I attempted, with dismal intraprocedural results; I concluded the technique was neither valid nor reproducible.