Otsubo Shunya, Takemoto Masao, Nyuta Eiji, Tsuchihashi Takuya
Cardiovascular Centre, Social Medical Corporation Steel Memorial Yawata Hospital, 1-1-1 Haruno-machi, Yahatahigashi-ku, Kitakyushu 805-8508, Japan.
Eur Heart J Case Rep. 2025 Jan 16;9(1):ytaf016. doi: 10.1093/ehjcr/ytaf016. eCollection 2025 Jan.
The superior vena cava (SVC) acts as a non-pulmonary vein (PV) trigger for atrial fibrillation (AF) in 2%-6% of patients and harbours 25%-40% of non-PV foci. Approximately 10% of patients with AF have epicardial connections (ECs) between the atrium and PV inside the PV isolation lines, which are associated with AF recurrence. However, the contribution of EC(s) between the SVC and right atrium (RA) to subsequent AF remains unknown.
A 76-year-old woman underwent ablation for recurrent AF. She had undergone cryo-balloon ablation for paroxysmal AF 3 years previously. After confirming the complete entrance and exit blocks of the four PVs, SVC firing-induced AF was observed. After SVC isolation, the EC between the SVC and RA was observed. No AF was induced after EC ablation.
Although the mechanisms of ECs in the SVC and RA have not been entirely elucidated, several potential mechanisms have been proposed. (i) Anatomically inherited myofibres/bundles may run through the epicardial side between the SVC and RA. (ii) Epicardial connections between the right PV and the SVC or RA have been recently reported. Thus, we might speculate on the possibility of the existence of EC(s) between the right PV and both the SVC and RA. After cryoablation in the first session, the connection between the SVC and RA remained, which might have acted as EC(s). Thus, physicians should consider the possibility of EC(s) when remaining potentials in the SVC are observed, even though the SVC isolation line seems to be completed.
上腔静脉（SVC）在2% - 6%的患者中作为非肺静脉（PV）触发心房颤动（AF）的因素，且包含25% - 40%的非PV起源灶。约10%的AF患者在PV隔离线内的心房与PV之间存在心外膜连接（ECs），这与AF复发相关。然而，SVC与右心房（RA）之间的ECs对后续AF的影响尚不清楚。
一名76岁女性因复发性AF接受消融治疗。她3年前曾因阵发性AF接受过冷冻球囊消融。在确认四条PV完全实现入路和出路阻滞之后，观察到SVC触发导致的AF。在SVC隔离后，观察到SVC与RA之间的EC。EC消融后未诱发AF。
尽管SVC与RA中ECs的机制尚未完全阐明，但已提出了几种潜在机制。（i）解剖学上遗传的肌纤维/束可能穿过SVC与RA之间的心外膜侧。（ii）最近报道了右PV与SVC或RA之间的心外膜连接。因此，我们可能推测右PV与SVC和RA之间存在ECs的可能性。在首次冷冻消融后，SVC与RA之间的连接仍然存在，这可能起到了ECs的作用。因此，即使SVC隔离线似乎已完成，当观察到SVC中存在残留电位时，医生也应考虑ECs的可能性。
