• Age 18-years or older

• Ejection Fraction: ≥20% and ≤40% measured by transthoracic echocardiography (TTE) and assessed by an echocardiography (echo) core lab

• LV end-diastolic diameter ≥55 mm measured by TTE and assessed by an echo core lab

• Symptom Status:

‣ NYHA III,

⁃ NYHA ambulatory IV, or

⁃ NYHA II with a heart failure hospitalization within the prior 12 months (of signing the consent)

• Able to complete six-minute walk test with distance between 100 m and 450 m.

• Diagnosis and treatment for heart failure should be established at least 90 days before the date of consent. Subjects should be on stable, optimally titrated medical therapy for at least 30 days, as recommended according to current guidelines as standard-of-care for Heart Failure therapy, with any intolerance documented.

‣ Stable is defined as no more than a 100% increase or a 50% decrease of total daily doses. Medication changes within this range do not require any additional waiting before the screening assessments

⁃ When a total daily dose increase or decrease exceeds that which is considered stable, the screening TTE and CT will be postponed 30 days after the medication change

⁃ When additional titration is required to optimize a subject's medication that exceeds what is considered stable, the screening TTE and CT will be postponed at least 30 days after achieving the optimal dose (provided the optimal dose remains outside of the stable parameters)

⁃ When a dose-for-dose equivalent change in the class of medication change is made, no additional waiting is required before the screening assessments

⁃ When a change in class medication change exceeds what is considered stable, OR a new class of medication is added, the screening TTE and CT will be postponed 30 days after the medication change

⁃ If an SGLT2 inhibitor is added to a subject's medications, the screening TTE and CT will be postponed at least 30 days after the addition

⁃ If an SGLT2 inhibitor dose changes per the stable definition above, no additional waiting is required before the screening assessments

⁃ If an SGLT2 inhibitor dose change exceeds what is considered stable, the screening TTE and CT will be postponed at least 30 days after achieving the optimal dose (provided the dose remains outside of the stable parameters)

⁃ When applicable, for guideline-directed device-based therapies: a CRT device must be placed \> 90 days before the screening TTE and CT, and an ICD must be placed \> 30 days before the screening TTE and CT

• Able and willing to complete all qualifying diagnostic and functional tests, willing to accept blood product transfusion if required and agrees to comply with study follow-up schedule