American College of Cardiology Mar 29 2026 Adolescent patients with obstructive hypertrophic cardiomyopathy (HCM) who received the drug mavacamten saw a significant improvement in left ventricular outflow tract (LVOT) gradient, a measure of blood flow obstruction in the heart, compared with those who received a placebo, according to a small study presented at the American College of Cardiology's Annual Scientific Session (ACC.26). The trial is the first to test mavacamten in patients younger