Hypertrophic cardiomyopathy is a condition in which the heart muscle becomes unusually thick, which can make it harder for blood to flow out of the heart. In some people the condition causes no symptoms, but the thickened muscle can still create a blockage. The trial tests an oral tablet called aficamten taken at a dose of 20 mg each day and compares it with a placebo, which looks the same but does not contain the active drug. An additional substance, 68GA‑FAPI‑46, is used during special imaging scans to help visualize the heart.
The purpose of the study is to see whether aficamten can lower the pressure difference measured as the left ventricular outflow tract gradient after a breathing maneuver called the Valsalva maneuver. Participants will take the study medication for about one year, with regular visits that include a simple breathing test, ultrasound images of the heart (echocardiography), a magnetic resonance imaging scan, and a positron emission tomography/computed tomography scan that uses the 68GA‑FAPI‑46 agent. Blood samples will be taken to check biomarkers such as NT‑proBNP and hsTnT, which are substances that rise when the heart is under stress.
Throughout the study, the size and function of the heart, the thickness of the heart wall, and any signs of heart failure or irregular heart rhythm will be recorded. The results will show whether the study drug can safely reduce the blockage and improve heart measurements compared with the placebo.



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