Electroanatomical Voltage and Morphology Characteristics in Post-Infarction Patients Undergoing Ventricular Tachycardia Ablation: A Pragmatic Approach Favoring Late Potentials Abolition

BACKGROUND: -Catheter ablation is an important therapeutic option in post-myocardial infarction (MI) patients with ventricular tachycardia (VT). We analyzed the endo-epicardial electroanatomical mapping (EAM) voltage and morphology characteristics, their association with clinical data and their prognostic value in a large cohort of post-MI patients. METHODS AND RESULTS: -We performed total and segmental analysis of voltage (bipolar dense scar-DS and low voltage areas, unipolar low voltage and penumbra areas) and morphology characteristics (presence of abnormal late-LPs and early potentials-EPs) in 100 post-MI patients undergoing EAM-based VT ablation (26 endo-epicardial procedures) from 2010-12. All patients had unipolar low voltage areas while 18% had no identifiable endocardial bipolar DS areas. Endocardial bipolar DS area >22.5 cm2 best predicted scar transmurality. Endo-epicardial LPs were recorded in 2/3 patients, more frequently in non-septal myocardial segments and were abolished in 51%. Endocardial bipolar DS area >7 cm2 and endocardial bipolar scar density >0.35 predicted epicardial LPs. Isolated LPs are located mainly epicardially and EPs endocardially. As a primary strategy, LPs and VT-mapping ablation occurred in 48%, only VT-mapping ablation in 27%, only LPs ablation in 17% and EPs ablation in 6%. Endocardial LP abolition was associated with reduced VT recurrence and increased unipolar penumbra area predicted cardiac death. CONCLUSIONS: -Endocardial scar extension and density predict scar transmurality and endo-epicardial presence of LPs, although DS is not always identified in post-MI patients. LPs, most frequently located in non-septal myocardial segments were abolished in 51% resulting in improved outcome.