Abstract 14409: Clinical Usefulness of Immunohistochemistry for Plakoglobin in the Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy
Background: It is often challenging to diagnose arrhythmogenic right ventricular cardiomyopathy (ARVC) because the disorder has various clinical presentations and no pathognomonic tissue findings. Recently, several studies reported that a test for redistribution of desmosomal proteins can be used as a diagnostic tool for ARVC. Therefore, we evaluated whether immunohistochemistry for desmosomal proteins such as plakoglobin, N-cadherin, and nondesmosomal protein, connexin-43 can be a useful test in the diagnosis of ARVC based on the 2010 revised ARVC task force criteria.
Method: Fifty one endomyocardial biopsies from the patients with clinically definite and borderline ARVC (n=22), myocarditis (n=9) and normal autopsy controls (n=20) were analyzed. We correlated the immunohistochemcial features with the clinical diagnosis through a double-blinded manner, and we calculated sensitivity, specificity and predictive values.
Result: Reduced immunoreactivity for plakoglobin was observed in 12 (75%) of the 16 patients with a definite ARVC(fig.J) and 4 (67%) of the 6 patients with a borderline ARVC(fig.G). However, no control subjects showed reduced immunoreactivity(fig.A). Of the 9 patients with a diagnosis of myocarditis(fig.D), 2 subjects (22%) had a reduction of the immunoreactivity for plakoglobin. All subjects displayed no significant reduction of the immunoreactive level for connexin-43(fig.C,F,I,L) and N-cadherin(fig.B,E,H,K). The accuracy of the immunohistochemial analysis of plakoglobin was 80% for diagnosing ARVC. Sensitivity, specificity were 75% and 83%, and positive and negative predictive values were 67% and 88% respectively.
Conclusion: Our study showed that the analysis for plakoglobin had a relatively high sensitivity and specificity in the diagnosis of ARVC. We also confirmed that N-cadherin and Connexin-43 had no diagnostic values in ARVC.
Key Words: Plakoglobin, arrhythmogenic right ventricular cardiomyopathy
- © 2013 by American Heart Association, Inc.