Immune Checkpoint Inhibitor (ICI)-Associated Myocarditis

The observation of an association between the use of immune checkpoint inhibitors (ICIs) and the development of myocarditis is relatively recent. Despite the presumed low incidence of myocarditis, increasing use and the expansion of ICIs for treating different malignancies have led to an increase in the number of cases being seen in academic centers and the community. Any cardio-oncology practice must be equipped to recognize and treat this potentially fatal disease. The diagnosis of ICI-associated myocarditis is complicated and relies on a combination of clinical, laboratory, imaging, and biopsy findings. All patients with suspected ICI myocarditis should be admitted for assessment. Various treatment regimens have been reported with the mainstay of treatment involving cessation of the ICI and the administration of corticosteroids. The three cases presented below will highlight differences in clinical presentations, diagnostic tests, and treatments followed by an in-depth discussion of these differences.