Division of Imaging Sciences and Biomedical Imaging, King's College London, London, United Kingdom.
Cardiovascular Division, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom.
JACC Clin Electrophysiol. 2017 Sep;3(9):1006-1017. doi: 10.1016/j.jacep.2017.02.012.
This study sought to characterize direction-dependent and coupling interval-dependent changes in left atrial conduction and electrogram morphology in uniformly classified patients with paroxysmal atrial fibrillation (AF) and normal bipolar voltage mapping.
Although AF classifications are based on arrhythmia duration, the clinical course, and treatment response vary between patients within these groups. Electrophysiological mechanisms responsible for this variability are incompletely described.
Intracardiac contact mapping during incremental atrial pacing was used to characterize atrial conduction, activation dispersion, and electrogram morphology in 15 consecutive paroxysmal AF patients undergoing first-time pulmonary vein isolation. Outcome measures were vulnerability to AF induction at electrophysiology study and 2-year follow-up for arrhythmia recurrence.
Conduction delay showed a bimodal distribution, occurring at either long (high right atrium pacing: 326 ± 13 ms; coronary sinus pacing: 319 ± 16 ms) or short (high right atrium pacing: 275 ± 11 ms; coronary sinus pacing: 271 ± 11 ms) extrastimulus coupling intervals. Arrhythmia recurrence was found only in patients with conduction delay at long extrastimulus coupling intervals, and patients with inducible AF were characterized by increased activation dispersion (activation dispersion time: 168 ± 29 ms vs. 136 ± 11 ms). Electrogram voltage and duration varied throughout the left atrium, between patients, and with pacing site but were not correlated with AF vulnerability or arrhythmia recurrence.
Within the single clinical entity of paroxysmal AF, incremental atrial pacing identified a spectrum of activation patterns correlating with AF vulnerability and arrhythmia recurrence. In contrast, electrogram morphology (characterized by electrogram voltage and duration) was highly variable and not associated with AF vulnerability or recurrence. An improved understanding of the electrical phenotype in AF could lead to improved mechanistic classifications.
本研究旨在描述阵发性心房颤动（AF）患者中，在统一分类的情况下，左房传导和电图形态随激动方向和偶联间期的变化特征，这些患者的双极电压图正常。
尽管 AF 分类基于心律失常持续时间，但在这些组内的患者之间，临床病程和治疗反应存在差异。导致这种可变性的电生理机制尚不完全清楚。
在 15 例首次行肺静脉隔离的阵发性 AF 患者进行递增心房起搏期间，使用心内接触标测来描述心房传导、激动弥散和电图形态。研究终点为电生理研究时 AF 诱发的易感性和 2 年心律失常复发的随访结果。
传导延迟呈双峰分布，发生在长（高位右心房起搏：326±13ms；冠状窦起搏：319±16ms）或短（高位右心房起搏：275±11ms；冠状窦起搏：271±11ms）间期的附加刺激。仅在长偶联间期存在传导延迟的患者中发现心律失常复发，而可诱发 AF 的患者具有更高的激动弥散（激动弥散时间：168±29ms 比 136±11ms）。电图电压和持续时间在整个左心房、患者之间以及起搏部位之间变化，但与 AF 易感性或心律失常复发无关。
在阵发性 AF 的单一临床实体中，递增心房起搏可识别出与 AF 易感性和心律失常复发相关的一系列激活模式。相比之下，电图形态（由电图电压和持续时间来确定）高度可变，与 AF 易感性或复发无关。对 AF 中电生理表型的深入了解可能导致机械分类的改进。
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