title: High prevalence of myocarditis mimicking arrhythmogenic right ventricular cardiomyopathy differential diagnosis by electroanatomic mapping-guided endomyocardial biopsy.
abstract: OBJECTIVE
  We evaluated the diagnostic contribution and the therapeutic and prognostic implications of 3-dimensional electroanatomic mapping (EAM)-guided endomyocardial biopsy (EMB) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).
  
  
  BACKGROUND
  ARVC is a frequent cause of life-threatening ventricular arrhythmias and sudden death in young people. The value of current diagnostic criteria and the role of imaging techniques and EMB are still debated.
  
  
  METHODS
  We studied 30 consecutive patients (17 male, mean age 43 +/- 17 years) with a noninvasive diagnosis of ARVC according to current criteria. All patients underwent 3-dimensional EAM-guided EMB.
  
  
  RESULTS
  Twenty-nine (97%) of 30 patients presented an abnormal voltage map. Histology and immunohistochemistry confirmed the diagnosis of ARVC in 15 patients, and showed active myocarditis according to Dallas criteria in the remaining 15 patients. Patients with ARVC were not distinguishable on the basis of clinical features, presence, and severity of structural and functional right ventricular abnormalities and 3-dimensional EAM findings. On the basis of clinical and histological features, a cardioverter-defibrillator was implanted in 13 patients with biopsy-proven ARVC and in 1 patient only with myocarditis. At a mean follow-up of 21 +/- 8 months, 7 (47%) patients with ARVC experienced a recurrence of symptomatic sustained ventricular arrhythmias with appropriate defibrillator intervention in all cases. All patients with myocarditis remained asymptomatic and free from arrhythmic events.
  
  
  CONCLUSIONS
  Right ventricular myocarditis frequently mimics ARVC. Three-dimensional EAM-guided EMB is a safe and effective tool in differential diagnosis and in the selection of the most appropriate therapeutic strategy.
authors.affiliation: Cardiology Department, Catholic University, Largo A. Gemelli 8, Rome, Italy. mauriziopieroni@yahoo.com
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pieroni
authors.forename: Antonio
authors.initials: A
authors.lastname: Dello Russo
authors.forename: Francesca
authors.initials: F
authors.lastname: Marzo
authors.forename: Gemma
authors.initials: G
authors.lastname: Pelargonio
authors.forename: Michela
authors.initials: M
authors.lastname: Casella
authors.forename: Fulvio
authors.initials: F
authors.lastname: Bellocci
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
mesh_terms: D000328:Adult; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000175:diagnosis* / Q000473:pathology; D001707:Biopsy, Needle / Q000379:methods; D018780:Body Surface Potential Mapping; D003937:Diagnosis, Differential; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D009205:Myocarditis / Q000175:diagnosis* / Q000473:pathology; D009206:Myocardium / Q000473:pathology*