Abstract 17531: Importance of Programmed Stimulation Under Conscious Sedation for Patients Referred for Epicardial Ventricular Tachycardia Ablation
Background: Many non-ischemic cardiomyopathy (NICMP) patients referred for catheter ablation undergo an up-front epicardial approach under general anesthesia (GA). However, GA may suppress inducibility and decrease tolerance of induced ventricular tachycardia (VT), precluding detailed mapping, and leaving substrate modification as the sole ablation method.
Methods and Results: We tested a strategy of initial programmed electrical stimulation (PES) under light sedation, with conversion to GA and epicardial access if VT morphology and/or endocardial mapping suggested an epicardial substrate. Between January 2013 and May 2014, 12 NICMP patients (mean age 50 years, range 28-77; 75% male; EF 39 ± 17%) were referred for epicardial VT ablation. Patients had dilated CMP (n=7), ARVC (n=4), and Chagas disease (n=1). All underwent PES under conscious sedation, with 11 inducible for unstable (n=2) or stable (n=9) VT (median 2 VTs per patient, range 1-5; mean cycle length 341 ms, range 300-472). The noninducible/unstable VT patients underwent substrate modification based on voltage and pace-mapping of induced VT morphologies. Of the 9 patients with stable VT, 2 had VTs mapped and ablated in the epicardium, while 7 had VTs mapped with entrainment to the RV endocardium (n=5; 2 tricuspid annulus, 2 septum, 1 moderator band (Fig 1)), or LV (n=2; left coronary cusp, basal inferoseptal endocardium). All 7 VTs were successfully ablated, and 5 of these were ablated in areas of normal endocardial voltage. After ablation, the clinical VT was non-inducible with PES in all patients.
Conclusion: An initial approach of PES and entrainment mapping under conscious sedation is critically important for patients with NICMP referred for epicardial ablation. Empiric ablation of endocardial and epicardial scar would have missed the VT in 5/12 patients. RV endocardial circuits are not uncommon in this population (42%) and are difficult to identify without detailed entrainment mapping.
Author Disclosures: B. Nazer: None. N. Badhwar: None. C. Woods: None. T. Dewland: None. B. Moyers: None. E.P. Gerstenfeld: None.
- © 2014 by American Heart Association, Inc.