Electrical Isolation of the Superior Vena Cava: An Adjunctive Strategy to Pulmonary Vein Antrum Isolation Improving the Outcome of AF Ablation

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Abstract
PV isolation at the antrum (PVAI) has improved safety and efficacy of ablation procedures for atrial fibrillation (AF). AF triggers from the superior vena cava (SVC) may compromise the outcome of PVAI. We evaluated the (1) incidence of SVC triggers, (2) feasibility of empiric SVC electrical isolation (SVCI) as an adjunct to PVAI, and (3) SVCI safety. Of 190 patients (group I), 24 (12%) showed SVC triggers. Following PVAI, seven patients had AT originating from the SVC and three had AF. After SVCI, all 24 patients were arrhythmia-free 450 +/- 180 days post procedure. In the subsequent 217 patients (group II), empirical SVCI was performed following PVAI. Sixty-six of all 407 patients (16%) experienced recurrence of AF. A repeat procedure in 25 of the 66 patients showed that five (20%) had AF recurrence initiated by SVC triggers, of whom four were among group I patients (4/190; 2%) and one was from group II (1/217; 0.4%), (P < 0.05). Transient diaphragmatic paralysis can be avoided by pacing at the lateral aspect of the SVC using high output (30 mA). There was no SVC stenosis on CT scans before or 3 months after the procedure. There was no sinus node injury. The SVC harbors the majority of non-PV triggers of AF. SVCI is feasible, safe, and may be considered as an adjunctive strategy to PVAI for ablation of AF. The long-term favorable outcome of this hybrid approach remains to be evaluated in a larger series of patients.