Evaluating Cardiac Contractility Modulation in Heart Failure Patients

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). A historical echo within 60 days of consent may be used for baseline. Ultrafiltration should not be performed within 30 days of echo;
5. Subjects must meet at least one of the four following criteria:

   I. Heart failure admission (primary or secondary) within 12 months prior to study consent OR heart failure visit requiring IV therapy OR treated with outpatient Furoscix OR intensification of oral diuresis within 6 months prior to study consent II. PCWP \> 15 mmHg up to 6 months prior to consent or within 30 days following consent III. IPAP reading of mean pressure ≥ 22 mmHg in 2 or more readings within 30 days of consent, or 3 or more readings within 60 days across different days, with a sensor implanted ≥ 3 months before first reading

   IV. Natriuretic peptide value (NTproBNP or BNP) should meet or exceed the value below, depending on the presenting rhythm:
   * Normal Sinus Rhythm (NSR): NTproBNP (pg/ml) ≥ 150 or BNP (pg/ml) ≥ 50
   * Atrial Tachyarrhythmia (AT): NTproBNP (pg/ml) ≥ 450 or BNP (pg/ml) ≥ 150
   * Historical natriuretic peptide values within 6 months of consent may be used if subject is in NSR. Subjects in AT on baseline ECG must have natriuretic peptide values collected post-consent.
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. Spironolactone used as a diuretic for patients who cannot tolerate oral loop diuretic is an acceptable alternative.
   * 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. Diagnosis of any of the following conditions that, in the opinion of the investigator, contributes significantly to the primary symptoms of exercise intolerance: angina, significant pulmonary disease, or currently requires 24-hour home oxygen use or scheduled oral steroids, peripheral vascular disease, orthopedic or rheumatologic conditions;
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. Infiltrative/restrictive (e.g., amyloidosis, sarcoidosis, hemochromatosis, Fabry, or radiation-induced heart disease), eccentric LV hypertrophy or inflammatory cardiomyopathy as documented in the medical record;
11. Unstable angina pectoris within 30 days prior to study consent;
12. 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.
13. 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;
14. Myocardial infarction within 90 days prior to study consent;
15. Prior heart transplant or ventricular assist device;
16. Planning to become pregnant during the study;
17. Dialysis (permanent) or GFR \<15 ml/min/1.73m2;
18. Participating in another investigational drug or device study that may interfere with the interpretation of study data;
19. 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;
20. Expected lifespan of less than 18 months from time of study consent;
21. Unable to follow through study protocol for any reasons (social support, incarceration, mental illness etc.) in the investigator's judgement.
22. Insurance denial (after all attempts and appeals have been exhausted, and prior-authorization services utilized, if applicable)