Differential Diagnosis of ARVC/D

In this chapter, we will describe in detail, the mimics of the arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). There are several disorders predominantly involving the right ventricular myocardium and leading to structural abnormalities that could be easily interpreted by inexperienced imager as these are consistent with the ARVC/D. We will focus on some of these pathologic conditions associated with the RV changes reminding those of the RV dysplasia and frequently reaching extent and severity requiring review of task force criteria. Disorders such as cardiac sarcoidosis, myocarditis, pulmonary hypertension, and some congenital abnormalities may be easily mixed up with the ARVC/D. Moreover, these disorders may lead to a significant RV and left ventricular (LV) fibrosis, and subsequent ventricular arrhythmias mimicking electrocardiography-based criteria of the ARVC/D. Serious diagnostic skills and knowledge are needed to carefully review the entire clinical picture and create a differential diagnosis list for all the cases when the ARVC/D is suspected. In this chapter, we will also describe normal variants and a few benign clinical conditions that may have CMR appearance of the ARVC/D. It is especially important in this regard to distinguish the disorder with a normal variant of the "athlete's heart." We provide a simple approach allowing to utilize the entirety of the clinical data in each case in order to come up with an understanding of the "posttest likelihood" of the ARVC/D vs. the ARVC/D mimic. Several clinical examples from the published evidence demonstrate diagnostic dilemmas and difficulty in differential diagnosis of ARVC/D, as well as the most effective approach to diagnosis in these patients.