Abstract
PurposeLeft atrial (LA) rapid AF activity has been shown to co-localise with areas of successful atrial fibrillation termination by catheter ablation. We describe a technique that identifies rapid and regular activity.MethodsEight-second AF electrograms were recorded from LA regions during ablation for psAF. Local activation was annotated manually on bipolar signals and where these were of poor quality, we inspected unipolar signals. Dominant cycle length (DCL) was calculated from annotation pairs representing a single activation interval, using a probability density function (PDF) with kernel density estimation. Cumulative annotation duration compared to total segment length defined electrogram quality. DCL results were compared to dominant frequency (DF) and averaging.ResultsIn total 507 8 s AF segments were analysed from 7 patients. Spearman’s correlation coefficient was 0.758 between independent annotators (P < 0.001), 0.837–0.94 between 8 s and ≥ 4 s segments (P < 0.001), 0.541 between DCL and DF (P < 0.001), and 0.79 between DCL and averaging (P < 0.001). Poorer segment organization gave greater errors between DCL and DF.ConclusionDCL identifies rapid atrial activity that may represent psAF drivers. This study uses DCL as a tool to evaluate the dynamic, patient specific properties of psAF by identifying rapid and regular activity. If automated, this technique could rapidly identify areas for ablation in psAF.
Highlights
Rapid cycle length activity (110–270 ms) from the pulmonary veins plays a role in the initiation of atrial fibrillation (AF).[12]
Atrial fibrillation cycle length (AFCL), measured as local activations determined from intracardiac electrograms in the atria, has been used to assess response to pulmonary veins (PVI), vagal stimulation, complex fractionated electrogram ablation, and interrogation of regional differences in AF with averaging over consecutive cycles.[13,16,20,25]
We have shown that our method is capable of returning a cycle length as simple averaging, with the significant difference of the potential for automation, and the potential for determining dominant cycle length (DCL) without pre-selection of electrograms based on quality
Summary
Rapid cycle length activity (110–270 ms) from the pulmonary veins plays a role in the initiation of atrial fibrillation (AF).[12]. Atrial fibrillation cycle length (AFCL), measured as local activations determined from intracardiac electrograms in the atria, has been used to assess response to PVI, vagal stimulation, complex fractionated electrogram ablation, and interrogation of regional differences in AF with averaging over consecutive cycles.[13,16,20,25]. Non-pulmonary vein drivers of psAF may manifest as rapid AFCL, high frequency areas, that exhibit rotational activity, with gradients within the atrial tissue.[21]. Our AFCL evaluation method, dominant cycle length (DCL), surmounts the issue of transient loss of electrograms that may skew averages and distort results. We use DCL to locate areas of rapid activation, that might serve as targets for extra-pulmonary vein driver ablation in psAF. We introduce metrics that describe the quality of electrograms, and consistency of AF within a time period
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