Pembrolizumab: Myocarditis.

A 42-year-old woman developed myocarditis after receiving pembrolizumab treatment for breast cancer. She experienced symptoms of heart failure, elevated troponin levels, and complete heart block. The woman was hospitalized and received temporary venous pacing. She was treated with steroids and her condition improved, with native conduction recovering and the pacing wire being removed. Cardiac MRI confirmed the diagnosis of pembrolizumab-induced myocarditis. The woman was discharged with a prolonged taper of oral steroids and close follow-up. [Extracted from the article]