Introduction:
Pembrolizumab is a humanized IgG4 antibody that disrupts the interaction between programmed cell death protein 1 (PD1) and programmed death-ligand 1 (PDL1)1. It belongs to the immune-checkpoint inhibitors (ICI) class, which has been shown to enhance clinical outcomes in a variety of solid organ cancers2. Despite positive therapeutic outcomes, this new medicine is associated with a slew of negative side effects. Pembrolizumab-related immune-related side effects include myocarditis and neuromuscular side effects are uncommon. However, there is growing evidence of an increased risk of ICI-related myocarditis. There is no clarity on diagnosis or therapeutic management that we are aware of. Myocarditis, cardiomyopathy, heart failure, and arrhythmias are all associated cardiotoxicities. The offending agent is usually stopped in the majority of cases of immune checkpoint inhibitor cardiotoxicity3. We discuss a case of a patient who developed cardiomyopathy as a result of pembrolizumab treatment and was successfully managed.