Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows:. Primary objective To assess the effects of myosin inhibitors compared to usual care or placebo on exercise capacity, need for septal reduction therapy, and all-cause mortality in people with hypertrophic cardiomyopathy (HCM). Secondary objectives To assess the effects of myosin inhibitors compared to usual care or placebo in people with HCM in the following population subgroups. By demographics, such as age and sex Obstructive HCM versus non-obstructive HCM Genotype-negative and genotype-positive disease People with and without pre-existing atrial fibrillation or other types of arrhythmias.