Abstract 3097: Epicardial and Endocardial Substrate Mapping and Radio Frequency Ablation of Ventricular Tachycardia in Patients with Chronic Chagasic Cardiomyophathy
Introduction: Scar map and radiofrequency ablation (RFa) have been used to treat sustained ventricular tachycardia (VT) in patients (pt) with ischemic heart disease. Although entrainment map indicates endocardial (END) and epicardial (EP) reentry as the mechanism of chronic chagasic cardiomyophathy (CCC), the anatomical substrate of this arrhythmia has not been well characterized. Further, the value of substrate map for VT ablation in CCC is uncertain.
Objective: We evaluated EP and END substrate map and RFa of VT in CCC.
Methods: 12pt (5 male, 52±12y.o, LVEF% 43±12, ICD in 11) with drug refractory VT and multiple ICD shocks underwent EP and END voltage (V) map with the CARTO XP system. V<0.5mV were considered scar and > 1.5mV normal tissue. The duration of Bip electrogram was measured in 10 different points of normal and scar tissues in EP surface.
Results: EP scar area was 28±17cm2 and END scar area was 16±11cm2 (p=0.001). Bipolar potential duration in normal EP was 42.9±7.4ms and in the EP scar this duration was 83.43±15.7ms. RFa was guided by early systolic and entrainment techniques in 5pt, fragmented potentials in sinus rhythm in 4pt and linear lesions in 4pt. Acute success was obtained in 76,9% pt with no complications.
Conclusions: Large myocardial scars characterize the substrate for VT in CCC. Interestingly, scars are larger in the EP as compared to the END. This observation further supports the major role of EP circuits in the genesis of VT in CCC. Potential duration on the EP scar can facilitate differentiation of real scar from fat tissue. Electro-anatomic map is useful for VT ablation in CCC and may improve procedural success, particularly in hemodinamically unstable arrhythmias.