Abstract 14605: Epicardial/Endocardial Ablation for Inappropriate Sinus Tachycardia After Failed Endocardial Ablation
Introduction: Refractory inappropriate sinus tachycardia (IST) can be treated by sinus node ablation. The long term success of endocardial (EN) ablation is limited by the epicardial (EP) location of the sinus node (SN) and potential damage to the phrenic nerve (PN). An EP approach may offer enhanced access to SN and allow protection of the PN.
Methods: Patients with IST who failed prior EN SN ablation either due to recurrence or limitation by PN capture at intended ablation sites were offered EP ablation, with balloon protection of the PN if needed. Under general anesthesia, percutaneous subxyphoid pericardial access was obtained with double wire technique for PN protection. Earliest activation during sinus rhythm was mapped and ablated with radiofrequency (RF). Further ablation was guided by remapping P wave morphology or sinus rate changes. For patients with atrial pacing (AP) in place or planned, endpoint was sinus arrest; otherwise target was a decrease in sinus rate of at least 25% and inversion of P wave inferiorly.
Results: 5 patients (all female, age 36±4 years) underwent ablation.Two had prior AP, and one elected to have SN ablation and pacemaker during the same procedure. Three had prior EN ablation limited by PN, 4 had 1 prior attempt, 1 had 4 prior attempts. Baseline sinus rate was 119± 20 bpm. After 35.2±21.3 total RF lesions (22.4±21.7 EP, 12.8±21.3 EN), 4 were in junctional rhythm (two showed evidence of dissociated SN activity), one in annular rhythm at 90 bpm.This patient had symptom recurrence and underwent combined minimally invasive surgical/catheter cryoablation of the SN. Atrial tachycardia recurred and was successfully ablated at 12 o’clock on the tricuspid valve. 3 developed pericarditis requiring treatment. At last follow up (15.7±11.5 months), all had resolution of IST and pericarditis symptoms. Two were AP >99%, 1 was AP 61%, but max rate was 130 bpm (vs 200 bpm pre-ablation) on treadmill. One remains in a low atrial rhythm (inverted P wave inferiorly in one) in the 60s and 1 in the 80s (upright P wave), both without symptoms.
Conclusions: Combined EP/EN sinus node ablation is a viable approach for patients with severely symptomatic IST after a failed EN ablation. Pericarditis may occur in a significant proportion of patients, but eventually resolves.
- © 2012 by American Heart Association, Inc.