Objectives: This study sought to assess long-term arrhythmic risk in patients with myocarditis who received an implantable cardioverter-defibrillator (ICD). Background: The arrhythmic risk of patients with myocarditis overtime remains poorly known. Methods: The study enrolled 56 patients with biopsy-proven myocarditis who received an ICD for either primary (57%) or secondary prevention (43%) according to current guidelines. Clinical characteristics, biopsy findings, electrophysiological data from endocardial 3-dimensional electroanatomic voltage mapping, and device interrogation data were analyzed to detect arrhythmic events overtime. Coronary angiography excluded significant coronary artery disease in all patients. Results: At a mean follow-up of 74 ± 60 months (median 65 months), 25 (45%) patients had major ventricular arrhythmias treated by ICD intervention (76% being terminated by ICD shock and 24% by antitachyarrhythmia burst pacing). At multivariable analysis, the presence of sustained ventricular tachycardia on admission (hazard ratio: 13.0; 95% confidence interval: 2.0 to 35.0; p = 0.032) and the extension of the areas of low potentials at the bipolar endocardial mapping (hazard ratio: 1.19; 95% confidence interval: 1.04 to 1.37; p = 0.013) were the only independent predictors of appropriate ICD interventions. A cutoff value of 10% of abnormal bipolar area at electroanatomical ventricular mapping discriminated patients with appropriate ICD interventions with a sensitivity of 89% and a specificity of 85%. Conclusions: The study demonstrates that the prevalence of life-threatening ventricular arrhythmias in patients with myocarditis receiving an ICD according to current guidelines is high and the arrhythmic risk persists late overtime. Electroanatomical ventricular mapping may be a useful tool to identify patients at greater arrhythmic risk.
Long-Term Arrhythmic Risk Assessment in Biopsy-Proven Myocarditis / Pelargonio, G.; Pinnacchio, G.; Narducci, M. L.; Pieroni, M.; Perna, F.; Bencardino, G.; Comerci, G.; Dello Russo, A.; Casella, M.; Bartoletti, S.; Russo, E.; Crea, F.. - In: JACC. CLINICAL ELECTROPHYSIOLOGY. - ISSN 2405-500X. - 6:5(2020), pp. 574-582. [10.1016/j.jacep.2019.12.010]