CORRESPONDENCE: LETTER TO THE EDITOR
Diagnosis of Myocarditis Mimicking Arrhythmogenic Right Ventricular CardiomyopathyThe Role of Endomyocardial Biopsy Guided by Electroanatomic Voltage Map
Andrea Avella, MD* and
Giulia d'Amati, MD, PhD
* Cardiology Division, Cardiac Arrhythmia and Heart Failure Research Institute, St. Camillo-Forlanini Hospital, Via Portuense 332, 00149, Rome, Italy (Email: andrea.avella{at}tin.it).
Pieroni et al. (1) recently reported a 50% prevalence of right ventricular (RV) myocarditis in a cohort of 30 patients fulfilling standardized diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy (ARVC). The differential diagnosis between myocarditis and ARVC was obtained by performing electroanatomic mapping of the RV and then focusing, "for the first time," an endomyocardial biopsy (EMB) on selected pathological areas characterized by low-voltage potentials (electroanatomic mapping-guided EMB). Adopting this "novel diagnostic technique," Pieroni et al. (1) significantly modified the initial ARVC diagnosis.
We would like to make some comments regarding this study and its results. First, to the best of our knowledge, this is not the first report describing the electroanatomic mapping-guided EMB since this "novel diagnostic technique" has already been exhaustively described by our group (2,3). In particular, in 2008, we published the first report (3) documenting the feasibility of RV voltage mapping-guided EMB in a series of 16 consecutive patients with clinical evidence or suspicion for ARVC.
Second, contrary to the findings reported by Pieroni et al. (1), in our study (3), we did not observe histological evidence of myocarditis in any of the 16 patients with clinical evidence or suspicion for ARVC, in whom a pathological RV voltage map was documented. Up to now, we have been performing EMB targeting RV low-voltage areas in more than 40 patients with clinical evidence or suspicion for ARVC, and we have never observed evidence of active or borderline myocarditis according to the Dallas criteria. Our findings, in agreement with the observations of Corrado et al. (4), seem logical: since myocarditis usually has a patchy distribution in the heart chambers, it is unlikely to produce solid transmural scars detectable as low-voltage areas with endocardial electroanatomic mapping.
Third, in the study of Pieroni et al. (1), the most frequently involved RV regions (Table 2 of their study), in descending order, were the outflow tract (77%), the anterior free wall (50%), and the posteroinferior wall (43%), whereas the RV apex and the septal wall were less frequently involved (13% and 3%, respectively). Coherently, the authors included in the article 2 RV voltage maps, obtained from representative patients with ARVC (Fig. 2D of their study) and myocarditis (Fig. 3D of their study), both showing pathological areas in RV free wall and outflow tract, but normal potentials in the apex. Nevertheless, the authors provided in the article only a fluoroscopic demonstration of biopsy sampling in the RV apex (Fig. 1 of their study) but not a demonstration of biopsy sampling in the RV free wall or outflow tract, as we did in our study (3).
Finally, in the Discussion section, Pieroni et al. (1) stated: "With regard to the safety of the invasive procedure, we must acknowledge that the high experience level of the cardiologist performing the biopsies could have minimized the risks related to this new approach...." In our opinion, this statement is methodologically misleading since, in order to reduce the risk profile of the voltage-guided biopsy procedure, the crucial point is to perform the sampling on the border zone and not on the thinner core of low-voltage areas, as we suggested in our study (3).
 |
References
|
|---|
1. Pieroni M, Dello Russo A, Marzo F, et al. High prevalence of myocarditis mimicking arrhythmogenic right ventricular cardiomyopathy: differential diagnosis by electroanatomic mapping-guided biopsy J Am Coll Cardiol 2009;53:681-689.[Abstract/Free Full Text]2. Avella A, Pappalardo A, d'Amati G, et al. Endomyocardial biopsy guided by electroanatomic voltage mapping in arrhythmogenic right ventricular cardiomyopathy: a case report J Cardiovasc Electrophysiol 2007;18:991-993.[CrossRef][Web of Science][Medline] 3. Avella A, d'Amati G, Pappalardo A, et al. Diagnostic value of endomyocardial biopsy guided by electroanatomic voltage mapping in arrhythmogenic right ventricular cardiomyopathy/dysplasia J Cardiovasc Electrophysiol 2008;19:1127-1134.[CrossRef][Web of Science][Medline] 4. Corrado D, Basso C, Leoni L, et al. Three-dimensional electroanatomic voltage mapping increases accuracy of diagnosing arrhythmogenic right ventricular cardiomyopathy/dysplasia Circulation 2005;111:3042-3050.[Abstract/Free Full Text]
Related Article
-
Reply
- Maurizio Pieroni, Francesca Marzo, Fulvio Bellocci, and Filippo Crea
J. Am. Coll. Cardiol. 2009 54: 665-666.
[Full Text]
[PDF]
|
Top
References