69-06: Combined analysis of unipolar and bipolar voltage mapping identifies recurrences after unmappable scar-related ventricular tachycardia ablation

Abstract

The Rhtyhmia mapping system (Boston Scientific) allows multielectrode mapping through an minibasket catheter, containing 64 electrodes, by automatical acquisition of electrograms. Methods and results: 45 patients (43 male, 62.7 + 13.8 years) underwent ventricular tachycardia (VT) ablation in 2 centers. 30 patients had Ischemic Cardiomyopathy (ICM), 12 were affected dy Idiopathic Dilated Cardiomyopathy (IDCM), 1 by Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC), 1 by Congenital Heart disease, 1 by Myocarditis.34 patients had an already implanted ICD and 9 patients had a CRT-D. Left ventricular ejection fraction was 39.7 + 13.1%.In 15 patients CT scanning was used before the procedure and 1 patients underwent both MRI and CT. In 30 (66.6%) patients the index ablation was the first VT ablation; the remaining patients had 1.7 + 1.0 previous VT ablations.Hemodynamic support with ECMO was used during the procedure in 3 patients. Purpose of the Study: Recent studies noted and supposed the possible coexistence of arrhythmogenic right ventricular cardiomyopathy and myocarditis (ARVC) and myocarditis, considering the frequent finding of fibro-fatty infiltration and inflammatory component at histology. Cardiac magnetic resonance (CMR) is the only imaging modality able to depict fibro-fatty infiltration and fibrosis as late gadolinium enhancement (LGE) deposition. The endomiocardial biopsy (EBM) plays an important role in the definitive diagnosis of ARVC. The aim was to investigate by CMR and EBM the possible coexistence of two pathologies. Method Used: From 2010 to October 2015, 62 patients were enrolled and underwent a CMR. For each patient a right ventricular (RV) mapping was performed identifying the scar areas in the bipolar-unipolar maps. We obtained the right ventricular samples trough the right femoral vein via a disposable biotome . All the samples obtained were guided by the electroanatomical voltage mapping. Summary of Results: EBM was performed in 62 patients. In 7, 4 % (¼ 12) cases the biopsy was non diagnostic due to a sampling error. 3% (¼6) aspecific. In the remaining 44 patients the biopsy showed the presence of adipose infiltration with fibrosis with a diagnosis of ARVC in 18 (7,9%) patient, in 10 (4,4%) an histological inflammatory infiltrate as a myocarditis. In 16 patients (7%) the biopsy shows both a fatty infiltration and an inflammatory component. In all cases of ARVC in the intraventricular septum and RV anterolateral wall LGE was noted. In none of patients, with a no istopatological diagnosis of ARVC was noted fibrofatty-infiltration at CMR. In all patients with a istopatological myocarditis the LGE pattern was midwall patchy. In remaining patients with a coexistence of ARVC and an inflammatory component the CMR presented only diagnostic criteria for ARVC, and no suspicion of myocarditis LGE pattern. Conclusions: In our experience in the most cases there is a concordance between the CMR and EBM in terms of scar areas-LGE and fibrosis in the istopathological finding. Despite the CMR was not ...