As cancer treatment improves and survival rates increase, the long- and short-term side-effects of these treatments become more of a concern. One such side-effect is autoimmune myocarditis, or cardiac muscle inflammation, which can occur in patients undergoing treatment with immune checkpoint inhibitors (ICIs), a class of drugs used in cancer therapy. Although autoimmune myocarditis is a rare side-effect affecting only 0.1-1% of patients being treated with ICIs, it has a high fatality rate at 25-50% of cases.