Some people have a thick wall, called the septum, in their heart which can block blood flow and cause serious heart issues like shortness of breath and chest pain. The SESAME study is testing a new way to treat this problem. This involves a procedure where doctors remove extra tissue from the thick septum. During the procedure, patients will be asleep and doctors will use special tubes to take pictures and cut away the tissue safely. Participants will need to stay in the hospital for 2 to 6 days.

To join the study, participants need to be at least 21 years old and have a condition known as "left ventricular outflow tract obstruction" (LVOTO). Participants will have three follow-up visits within a year after the procedure to check how they are doing.

• The study requires a hospital stay of 2 to 6 days.
• Participants must be willing to come back for follow-up visits.
• The procedure carries some risks, including the risk from being partially or fully asleep.