Author(s): Berte B, Sacher F, Cochet H, Mahida S, Yamashita S,
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Abstract BACKGROUND: Nonischemic cardiomyopathy is a heterogeneous condition providing a favorable substrate for ventricular tachycardia (VT). OBJECTIVE: The purpose of this study is to further characterize the substrate in a subset of postmyocarditis patients with epicardial-only scar. METHODS: Twelve postmyocarditis patients (11 male, 49 ± 14 years, left ventricular ejection fraction 49 ± 12\%) with VT and epicardial-only scar were included for analysis comparing automatic high-amplitude normal activity (HANA) maps to manually adjusted maps of based on local abnormal ventricular activity (LAVA) electrograms when present. A combined endocardial (endo) and epicardial (epi) approach was used in 11/12 with usual bipolar/unipolar voltage thresholds and analyzed using image integration. RESULTS: A delayed enhancement MRI scar area of 52 cm(2) (38, 59) and multidetector CT wall thinning area of 18 cm(2) (14, 35) was found. Bipolar voltage substrate mapping (160 points [101, 239] endo, 553 points [232, 713] epi and LAVA were found only epicardially [443 LAVA points] in all) illustrated a low-voltage area of HANA: 1 cm(2) (0, 10) endo, 25 cm(2) (22, 39) epi and LAVA: 1 cm(2) (0, 10) endo, 39 cm(2) (28, 51) epi. Manual maps performed better than automatic maps for delineating low-voltage area with a higher overlap with scar area on delayed enhancement magnetic resonance imaging (DE-MRI; 76\% [66, 94] vs. 45\% [35, 62]; P = 0.04). In addition, manual voltage maps also showed a higher overlap with location of LAVA (LAVA in normal voltage area: 3\% [0, 9] vs. 35\% [32, 41]; P < 0.05). CONCLUSION: In postmyocarditis patients with epicardial-only scar, automatic voltage mapping may miss or minimize the electrical VT substrate. DE-MRI and manual LAVA-based voltage mapping are necessary to optimize scar delineation. Epicardial access is critical for mapping and ablation in this condition. © 2014 Wiley Periodicals, Inc.
This article was published in J Cardiovasc Electrophysiol
and referenced in Rheumatology: Current Research