The Role of Superior Vena Cava Isolation in the Management of Atrial Fibrillation

Abstract

The superior vena cava (SVC) has been identified as one of the most common sources of non-pulmonary vein triggers for atrial fibrillation (AF). SVC isolation has been shown to improve long-term maintenance of normal sinus rhythm in patients with paroxysmal AF. However, ablation at the SVC is associated with risks of phrenic nerve injury, sinus node dysfunction, and SVC stenosis. The use of electroanatomical mapping, intracardiac echocardiography, compound motor action potentials, and segmental (rather than circumferential) ablation are all strategies to reduce complications. Given these risks, SVC isolation is most effective as an adjunct to pulmonary vein isolation for patients with paroxysmal AF who have been found to have an arrhythmogenic SVC.

Keywords: Atrial fibrillation; catheter ablation; superior vena cava; vena cava.

Figure 1:

(a) Multi-electrode electrograms inside the superior vena cava (SVC) junction with far-field right atrium potentials (*) and sharp SVC sleeve potentials . Following SVC isolation, exit block can be seen in (b), with SVC pacing resulting in transient myocardial sleeve capture (arrows), and dissociation from the atrium.

Figure 2:

Sinus rhythm activation map. The white dots represent phrenic nerve capture. Note the proximity of the right superior pulmonary vein to the superior vena cava (SVC), and the location of the sinoatrial node (SAN) at the anterolateral SVC-RA (right atrium) junction. Circumferential ablation of the SVC requires more cranially placed lesions at the lateral SVC to avoid SAN injury (arrows).

Figure 3:

The superior vena cava-right atrium (SVC-RA) junction (marked by an asterisk) at the inferior border of the right pulmonary artery (RPA) on intracardiac echocardiography. The right superior pulmonary vein can be seen inferiorly to the RPA. A multi-electrode mapping catheter is present in the SVC, just above the AVC-RA junction.