Assessment of CCM in HF With Higher Ejection Fraction

Inclusion Criteria:

1. Signed and dated informed consent form;
2. Male or non-pregnant female, 18 years or older;
3. Diagnosed with symptomatic heart failure;
4. LVEF ≥40 and ≤70% (as assessed by site echo);
5. A. Heart failure hospitalization within 12 months prior to study consent OR an urgent heart failure visit requiring IV therapy within 6 months prior to study consent OR B. If there is no heart failure hospitalization within 12 months prior to study consent OR an urgent heart failure visit requiring IV therapy within 6 months prior to study consent, an elevated BMI-adjusted natriuretic peptide value must be achieved (Refer to Table 1 in Section 9.2.6)
6. Subjects must meet one of the following conditions:

   * Have stable, scheduled oral loop diuretic treatment (not just PRN) for a minimum of 30 days before providing study consent unless there is a documented allergy or intolerance.
   * Eligibility for enrollment is maintained for patients on an SGLT2 inhibitor without prescribed concurrent standing loop diuretic therapy if investigators provide instructions for a flexible PRN diuretic regimen (deemed appropriate by the clinician in response to symptoms or weight gain) Note: Stable is defined as no more than a 100% increase or 50% decrease in dose within the last 30 days. A one-time hold of diuretic dosing for 24 hours during the 30-day period is allowed and not an exclusionary event.

Exclusion Criteria:

1. Resting ventricular rate \<50 or \>110 bpm;
2. Resting systolic blood pressure \<100 or ≥160 mmHg;
3. BMI greater than 46
4. Any severe valvular stenotic disease or any severe valvular regurgitation;
5. Mechanical tricuspid valve;
6. Complex congenital heart disease;
7. Exercise tolerance limited by a condition other than heart failure that, in the opinion of the investigator, contributes significantly to the primary symptoms of shortness of breath and/or exercise intolerance;
8. Unable to walk at least 100 meters or walks more than 450 meters during a 6MWT;
9. A KCCQ CCS score higher than 85;
10. Hypertrophic, infiltrative/restrictive or inflammatory cardiomyopathy;
11. Unstable angina pectoris within 30 days prior to study consent;
12. Acute, decompensated heart failure requiring IV therapy or ultrafiltration within 30 days prior to consent, in the hospital or an outpatient setting;
13. Receiving cardiac resynchronization therapy (CRT); NOTE: Subjects with active/ongoing cardiac resynchronization therapy (CRT) implanted more than one year ago are eligible for inclusion if they are currently classified as NYHA class III or higher.
14. Scheduled for a cardiac surgery or a percutaneous cardiac intervention (PCI) or have undergone cardiac surgery within 90 days or a PCI procedure within 30 days prior to study consent;
15. Myocardial infarction within 90 days prior to study consent;
16. Prior heart transplant or ventricular assist device;
17. Planning to become pregnant during the study;
18. Dialysis (permanent) or GFR \<15 ml/min/1.73m2;
19. Participating in another investigational drug or device study that may interfere with the interpretation of study data;
20. Currently undergoing active chemotherapeutic and/or radiation treatment for cancer or has a history of chemotherapy during the 2-year period prior to study consent;
21. Expected lifespan of less than 18 months from time of study consent;
22. Unable to follow through study protocol for any reasons in the investigator's judgement.