This clinical trial is focused on studying a condition known as symptomatic non-obstructive hypertrophic cardiomyopathy. This is a heart condition where the heart muscle becomes thickened without blocking blood flow, which can lead to symptoms like shortness of breath and chest pain. The study will evaluate a medication called Aficamten, which is being compared to a placebo. Aficamten is a film-coated tablet developed by Cytokinetics Inc. and is also known by its code name CK-3773274.

The purpose of the study is to assess how Aficamten affects the health status and exercise capacity of participants with this heart condition. Participants will be randomly assigned to receive either Aficamten or a placebo. The study will be conducted in a double-blind manner, meaning neither the participants nor the researchers will know who is receiving the actual medication or the placebo. This helps ensure the results are unbiased. The trial will last for a period of 72 weeks, during which participants will undergo regular assessments to monitor their health and response to the treatment.

Throughout the study, participants will have their exercise capacity measured, which involves evaluating how well they can perform physical activities. The study will also monitor changes in their heart condition and overall health. The goal is to determine if Aficamten can improve symptoms and quality of life for those living with symptomatic non-obstructive hypertrophic cardiomyopathy. This research could potentially lead to new treatment options for individuals affected by this heart condition.