Misdiagnosis of ARVC leading to inappropriate ICD implant and subsequent ICD removal - lessons learned.

INTRODUCTION: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited progressive cardiomyopathy characterized by frequent life-threatening arrhythmias. The diagnosis of ARVC is challenging and is on the basis of a set of major and minor criteria as described by the modified Task Force Criteria (TFC). We report our clinical experience in a series of patients who were misdiagnosed with ARVC and subsequently underwent removal of their implantable cardioverter defibrillator (ICD) after a re-evaluation at our center. METHODS AND
RESULTS: We studied 12 patients who were misdiagnosed with ARVC and had ICD implantation before our assessment. All patients had a repeat evaluation and were scored according to TFC before ICD removal. Cardiac magnetic resonance imaging (CMR) studies performed at outside institutions during the initial evaluation were reported abnormal and classified as meeting major TFC in ninety percent of patients. The most common abnormality reported was fatty infiltration of the right ventricular (RV) free wall and/or presence of focal intra-myocardial fat in six patients (50%). On re-evaluation, none of these findings fulfilled the TFC for the diagnosis.
CONCLUSION: This study demonstrated that high dependence on misinterpretation of CMR along with a misunderstanding of the TFC evaluation are the main reasons for the misdiagnosis of ARVC. Despite the updated criteria for almost a decade, this study reminds that the diagnosis of ARVC is complex and hence careful TFC evaluation and consideration of multiple cardiac test results should be the focused approach for clinicians when confronted with suspected ARVC patients.