Behind the curtain lies the truth: a case of arrhythmogenic cardiomyopathy mistaken for COVID-19 vaccine-associated myocarditis.

A 15-year-old male presented with vasovagal syncope and troponin leak 4 days after his second COVID-19 vaccine. Based on initial diagnostic work-up, he was thought to have COVID-19 vaccine-associated myocarditis. His cardiac dysfunction persisted and further work-up including genetic evaluation and serial MRI studies later confirmed a diagnosis of arrhythmogenic cardiomyopathy. This is a unique case of an incorrect diagnosis based on timing and context of vaccine-related myocarditis. Reports of mild and self-limited myocarditis post-COVID-19 vaccination may cause vaccine hesitancy among the public, and so case reports such as this one show the importance of discerning underlying conditions amongst rare COVID-19 vaccination complications.