Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy
Department of Biomedical Engineering and Center for Integrative Electrocardiology at Lund University (CIEL), Lund University, SE-22100 Lund, Sweden.
Europace. 2014 Nov;16 Suppl 4:iv129-iv134. doi: 10.1093/europace/euu246.
During atrial fibrillation (AF), conventional electrophysiological techniques for assessment of refractory period or conduction velocity of the atrioventricular (AV) node cannot be used. We aimed at evaluating changes in AV nodal properties during administration of metoprolol from electrocardiogram data, and to support our findings with simulated data based on results from an electrophysiological study.
Sixty patients (age 71 ± 9 years, 42 men) with permanent AF were included in the RATe control in Atrial Fibrillation (RATAF) study. Two 15 min segments, during baseline and metoprolol administration, starting at 2 pm were analysed in this study. Atrial fibrillatory rate (AFR), heart rate (HR), and AV nodal parameters were assessed. The AV nodal parameters account for the probability of an impulse not taking the fast pathway, the absolute refractory periods of the slow and fast pathways (aRPs and aRPf), representing the functional refractory period, and their respective prolongation in refractory period. In addition, simulated RR series were generated that mimic metoprolol administration through prolonged AV conduction interval and AV node effective refractory period. During metoprolol administration, AFR and HR were significantly decreased and aRP was significantly prolonged in both pathways (aRPs: 337 ± 60 vs. 398 ± 79 ms, P < 0.01; aRPf: 430 ± 91 vs. 517 ± 100 ms, P < 0.01). Similar results were found for the simulated RR series, both aRPs and aRPf being prolonged with metoprolol (aRPs: 413 ± 33 vs. 437 ± 43 ms, P = 0.01; aRPf: 465 ± 40 vs. 502 ± 69 ms, P = 0.02).
The AV nodal parameters reflect expected changes after metoprolol administration, i.e. a prolongation in functional refractory period. The simulations confirmed that aRPs and aRPf may serve as an estimate of the functional refractory period.
在心房颤动（AF）期间，不能使用评估房室（AV）结不应期或传导速度的传统电生理技术。我们旨在从心电图数据评估美托洛尔给药期间 AV 结特性的变化，并基于电生理研究结果的模拟数据支持我们的发现。
在 RATe 控制心房颤动（RATAF）研究中，纳入了 60 名（年龄 71±9 岁，42 名男性）永久性 AF 患者。本研究分析了在下午 2 点开始的基线和美托洛尔给药期间的两个 15 分钟段。评估了心房颤动率（AFR）、心率（HR）和 AV 结参数。AV 结参数反映冲动不采用快径的概率、慢径和快径的绝对不应期（aRPs 和 aRPf），代表功能不应期，以及各自在不应期中的延长。此外，生成了模拟 RR 系列，通过延长 AV 传导间隔和 AV 结有效不应期来模拟美托洛尔给药。在美托洛尔给药期间，在两条路径中，AFR 和 HR 均显著降低，aRP 均显著延长（aRPs：337±60 对 398±79 ms，P<0.01；aRPf：430±91 对 517±100 ms，P<0.01）。模拟 RR 系列也得到了类似的结果，美托洛尔给药时 aRPs 和 aRPf 均延长（aRPs：413±33 对 437±43 ms，P=0.01；aRPf：465±40 对 502±69 ms，P=0.02）。
AV 结参数反映了美托洛尔给药后的预期变化，即功能不应期延长。模拟证实 aRPs 和 aRPf 可作为功能不应期的估计值。
