A case of recurring myocarditis: Magnetic resonance, key to diagnosis

Arrhythmogenic cardiomyopathy is a hereditary disease characterized by the replacement of the myocardium by fibrofatty tissue. In recent years, three patterns have been described: the classic right variant, the biventricular variant, and the variant with predominant involvement of the left ventricle. Nowadays, cardiac magnetic resonance is a fundamental tool for diagnosis of arrhythmogenic left ventricular cardiomyopathy. Late gadolinium enhancement is a very sensitive indicator of early left-sided involvement, and is included as a marker in the current arrhythmogenic cardiomyopathy criteria. We report a case of arrhythmogenic left ventricular cardiomyopathy with atypical form of presentation as recurrent myocarditis. Clinical suspicion was important for the diagnosis, as the patient did not present data that would point to an infectious origin of the disease. However, the key to diagnosis was detecting a characteristic imaging pattern on cardiac magnetic resonance. Initially, a meso-subepicardial fibrosis located in lateral wall was observed, which progressively spread to other regions until it became practically global. In addition, irregularities were observed in the epicardial contour that were suggestive of fatty infiltration, all consistent with the diagnosis of arrhythmogenic left ventricular cardiomyopathy.

Arrhythmogenic left ventricular cardiomyopathy has recently been recognized as part of the arrhythmogenic cardiomyopathy spectrum. Given the difficulties in its diagnosis, it is essential to have a high index of suspicion. We must pay attention to the clinical context and the cardiac magnetic resonance imaging findings, which has become an essential imaging tool for diagnosis.