Focal Atrial Fibrillation from the Superior Vena Cava.

We report the case of a 66 year-old male who underwent catheter ablation for drug-refractory paroxysmal atrial fibrillation (AF) at our institution. Radiofrequency catheter ablation was performed using a three-dimensional electroanatomical mapping system. During ablation of the pulmonary veins (PV), right atrial ectopics were noted to repeatedly trigger AF and atrial tachycardia (AT). After PV isolation, mapping of the right atrium revealed that the superior vena cava (SVC) was in AF, while both atria were in an organized AT. Segmental ablation was performed around the SVC ostium, resulting in vein isolation and immediate restoration of sinus rhythm, while the SVC remained in AF. This case highlights the importance of the SVC in some AF patients as a potential source for non-PV triggers. SVC isolation can be safely achieved in most cases to improve outcomes.