Abstract 19032: Anatomic Isolation of Core Elements of Circuit Substrate with Ablation Eliminates Multiple Scar Based Ventricular Tachycardias
Introduction: Radiofrequency ablation (RFA) of multiple or unmappable ventricular tachycardias (VT) remains a challenge with unclear endpoints. We present our experience with a new strategy isolating core elements of VT circuits.
Methods: Patients with structural heart disease presenting for VT RFA at 2 centers were included. Strategy involved entrainment/activation mapping if VT was hemodynamically tolerated, and/or voltage mapping with electrogram analysis and pace mapping. Core isolation (CI) was performed incorporating putative isthmus and early exit site(s) based on standard criteria (panel A). If VT was noninducible, the dense scar (<0.5 mV) region was isolated. Successful CI was defined by exit block (20mA at 2 ms) within the “isolated” region. VT inducibility was also assessed.
Results: 44 patients undergoing CI were included (mean age 63, 95% male, 73% ischemic cardiomyopathy, mean LVEF 31%, 68% with multiple unstable VTs (mean 3+2)). CI area was 11+12 cm2, vs. 55+40 cm2 total scar area. Additional substrate modification was performed in 27 (61%), and epicardial RFA was performed in 4 (9%). CI was achieved in 37 (84%) and led to better VT free survival (log rank p=0.013), as well as added incremental benefit to acute VT noninducibility in improving long-term ablation success (panels B and C).
Conclusion: “Core isolation” is a novel strategy with a discrete and measurable endpoint beyond VT inducibility to treat patients with multiple and/or unmappable VTs. The CI region can be selected based on standard characterization of suspected VT isthmus surrogates thus limiting ablation target size. Exit block within the isolated area is achievable in most and may further improve long-term success.
Author Disclosures: W.S. Tzou: None. T. Hegeman: None. D.S. Frankel: None. W.H. Sauer: None. F.E. Marchlinski: None.
- © 2014 by American Heart Association, Inc.