An atrial tachyarrhythmias is predominantly triggered by a proarrhythmic activity originate from the pulmonary veins (PV) myocardial sleeves; sympathetic or adrenergic stimulation facilitates PV proarrhythmia. In the present study the electrophysiological inhomogeneity, spatiotemporal characteristics of the adrenergically induced ectopic firing and sympathetic nerves distribution have been investigated in a murine PV myocardium to clarify mechanisms of adrenergic PV ectopy. Electrically paced murine PV demonstrate atrial-like pattern of conduction and atrial-like action potentials (AP) with longest duration in the mouth of PV. The application of norepinephrine (NE), agonists of α- and β-adrenergic receptors (ARs) or intracardiac nerves stimulation induced spontaneous AP in a form of periodical bursts or continuous firing. NE- or ARs agonists-induced SAP originated from unifocal ectopic foci with predominant localization in the region surrounding PV mouth, but not in the distal portions of a murine PV myocardium. A higher level of catecholamine content and catecholamine fiber network density was revealed in the PV myocardial sleeves relative to LA appendage. However, no significant local variation of catecholamine content and fiber density was observed in the murine PV. In conclusion, PV mouth region appear to be a most susceptible to adrenergic proarrhythmia in mice. Intrinsic spatial heterogeneity of AP duration can be considered as a factor influencing localization of the ectopic foci in PV.

中文翻译：

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小鼠肺静脉心肌中的局部复极异质性有助于肾上腺素诱导的异位病灶的空间分布。


房性快速心律失常主要由源自肺静脉 (PV) 心肌袖的致心律失常活动引发；交感神经或肾上腺素能刺激促进PV致心律失常。在本研究中，我们在小鼠 PV 心肌中研究了电生理不均匀性、肾上腺素诱导的异位放电的时空特征和交感神经分布，以阐明肾上腺素能 PV 异位的机制。电起搏小鼠 PV 表现出心房样传导模式和心房样动作电位 (AP)，在 PV 口中持续时间最长。去甲肾上腺素（NE）、α-和β-肾上腺素能受体（AR）激动剂或心内神经刺激的应用以周期性爆发或连续放电的形式诱导自发性AP。 NE 或 AR 激动剂诱导的 SAP 起源于单灶异位病灶，主要定位于 PV 口周围区域，但不在小鼠 PV 心肌的远端部分。相对于 LA 附肢，PV 心肌袖中的儿茶酚胺含量和儿茶酚胺纤维网络密度较高。然而，在小鼠PV中没有观察到儿茶酚胺含量和纤维密度的显着局部变化。总之，PV 口腔区域似乎是小鼠最容易发生肾上腺素能致心律失常的区域。 AP 持续时间的内在空间异质性可被视为影响 PV 异位病灶定位的因素。