• Between 18-85 years of age

• Body mass index \< 40 kg/m2

• Diagnosed with nHCM and has a screening echocardiogram with the following:

‣ End-diastolic left ventricular (LV) wall thickness:

• ≥ 15 mm in one or more myocardial segments OR

∙ ≥ 13 mm in one or more wall segments and a known disease-causing gene mutation or positive family history of HCM AND

∙ Resting LVOT-G \< 30 mmHg AND Valsalva LVOT-G \< 50 mmHg AND

∙ LVEF ≥ 60%

⁃ Participants with a history of intracavitary obstruction are eligible.

• NYHA class II or III

• Respiratory exchange ratio of ≥ 1.00 at screening by cardiopulmonary exercise testing (CPET) and predicted peak oxygen uptake (pVO2) ≤ 90% for age and sex

• KCCQ-CSS score of ≤ 85

• NT-proBNP of:

‣ NT-pro BNP ≥ 300 pg/mL or NT-proBNP ≥ 900 pg/mL if in atrial fibrillation or atrial flutter OR

⁃ For Black participants, an NT-pro BNP ≥ 225 pg/mL or NT-proBNP ≥ 675 pg/mL if in atrial fibrillation or atrial flutter