Abstract 14689: Typical Ventricular Tachycardias and Underlying Arrhythmogenic Substrates in Nonischemic Dilated Cardiomyopathy: Implications for the Ablation Strategy
INTRODUCTION Typical ventricular tachycardia (VT) morphologies and underlying arrhythmogenic substrates have not been described in patients with nonischemic dilated cardiomyopathy (NICM), but may be used to guide the procedural strategy.
METHODS Nineteen consecutive patients with NICM who underwent contrast-enhanced MRI (CE-MRI) and VT-ablation were included. For each patient, the substrate morphology was studied using a 3D CE-MRI-derived scar reconstruction. Ablation target sites were defined as sites with a ≥11/12 pacemap, concealed entrainment or VT termination during ablation.
RESULTS In 19 patients (58±14 years, 79% male, LVEF 46±9%) 60 VTs were induced (cycle length 295±67ms). Nine patients (47%) had a subaortic scar, 8 (42%) an inferolateral scar and 2 (11%) other scar types. Eight out of 9 patients with a subaortic scar (89%) had a RBBB VT with inferior axis and positive concordance (n=6) and/or a LBBB VT with an inferior axis and precordial transition ≤V3 (n=5). Six of 8 patients with inferolateral scars (75%) had a RBBB VT with a right axis and precordial transition ≥V5. In the 9 patients with subaortic scars ablation target sites were located in the aortic root and/or subaortic LV endocardium in 8 (89%) and in the anterior cardiac vein in 1 (11%). Additional target sites were identified at the RV septum in 2 (22%) and at the epicardium in 1 (11%). In contrast, in 8 patients with inferolateral scars, target sites were located at the epicardium in 5 patients (63%) and in the LV endocardium in 3 patients (37%).
CONCLUSION Subaortic scars and inferolateral scars account for 89% of arrhythmogenic substrates in patients with NICM. Typical VT morphologies may help to identify the underlying substrate. Subaortic scars were in general most effectively approached from the aortic root or subaortic LV endocardium, while inferolateral scars frequently required an epicardial approach.
- Ventricular tachycardia
- Ablation, radiofrequency
- Catheter ablation
- Magnetic resonance imaging
- © 2012 by American Heart Association, Inc.