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Intern Med. 2017 August 15; 56(16): 2239–2240.
Published online 2017 August 1. doi:  10.2169/internalmedicine.8588-16
PMCID: PMC5596292

AF Sustained in Only a Small Area of SVC

A 66-year-old female was admitted to our hospital to undergo catheter ablation for symptomatic paroxysmal atrial fibrillation (AF). After pulmonary vein isolation was achieved by cryoballoon and adenosine triphosphate was injected to confirm the dormant conduction of the pulmonary veins, AF was induced. Sinus rhythm was restored by cardioversion, whereas AF was sustained only in the superior vena cava (SVC) (Picture 1 and and2).2). Mapping under a 3D mapping system revealed that AF was sustained in only a very small area of SVC (13.6 cm2) (Picture 3 and and4).4). All areas in SVC returned to sinus rhythm during the isolation of SVC.

SVC is important for non-pulmonary vein focus and the maintenance of AF. Conduction blocks and the heterogenicity of the histological structure in SVC has also been reported (1,2). This case was rare in the respect that we could detect a very small area of sustained AF in SVC using the 3D mapping system.

The authors state that they have no Conflict of Interest (COI).


1. Tsai CF, Tai CT, Hsieh MH, et al. Initiation of atrial fibrillation by ectopic beats originating from the superior vena cava. Electrophysiological characteristics and results of radiofrequency ablation. Circulation 102: 67-74, 2000. [PubMed]
2. Yeh HI, Lai YJ, Lee SH, et al. Heterogeneity of myocardial sleeve morphology and gap junction in canine superior vena cava. Circulation 104: 3152-3157, 2001. [PubMed]

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