Abstract
We discuss a case of a 60-year-old man with hypertrophic cardiomyopathy treated with the novel cardiac myosin inhibitor, mavacamten. Dynamic electrocardiogram patterns of left ventricular hypertrophy and left ventricular strain coincided with the patient starting mavacamten, discontinuing the drug, and then restarting mavacamten, highlighting electrocardiograms as accessible and inexpensive potential tools to monitor drug efficacy. This case also shows the ability of myosin inhibition to positively alter the adverse electrical changes associated with hypertrophic cardiomyopathy.