High prevalence of myocarditis mimicking arrhythmogenic right ventricular cardiomyopathy differential diagnosis by electroanatomic mapping-guided endomyocardial biopsy.
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.
Pieroni
Maurizio
M
Cardiology Department, Catholic University, Largo A. Gemelli 8, Rome, Italy. mauriziopieroni@yahoo.com
Dello Russo
Antonio
A
Marzo
Francesca
F
Pelargonio
Gemma
G
Casella
Michela
M
Bellocci
Fulvio
F
Crea
Filippo
F
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*