For the first time, medication has impacted heart muscle thickness and function for patients with the most common inherited heart condition, rather than simply addressing their symptoms. "This is the first study to show a favourable impact of a medication on cardiac structure and function in any form of hypertrophic cardiomyopathy," said Sara Saberi, M.D., an assistant professor of internal medicine and a cardiologist at the Michigan Medicine Frankel Cardiovascular Center. Current options, Saberi explains, might help patients feel better today, but they don't help them live longer, nor do they prevent people from experiencing heart failure down the road. They also don't affect any of the heart structural abnormalities that define the disease: the thickness of the heart muscle, resultant stiffness, and abnormalities in other cardiac structures. "There's a huge void. HCM is a chronic progressive disease that still does not have a cure," Saberi said. She presented the results of her team's EXPLORER-HCM CMR sub-study at the 2020 American Heart Association Scientific Sessions, which published simultaneously in Circulation. Addressing the underlying cause of HCM, In HCM, the motor proteins interact with each other too much, causing over-vigorous squeeze of the muscle and causing stiffness of the muscle. A medication designed specifically for HCM, mavacamten, is currently being studied in a variety of clinical trials. It's a part of a new class of drugs called cardiac myosin inhibitors. The medication works by blocking a protein called myosin from interacting too much with other motor proteins, which then allows the heart muscle to squeeze and relax more normally, Saberi explains. It is effective at reducing obstruction to blood flow within the heart that can occur with the disease.