CLINICAL TRIAL / NCT06678841

Inclusion Criteria: 1. Age ≥ 40 years 2. Documented EF ≥50% within the preceding 12 months 3. HFpEF defined as: 1. Documented worsening HF episode (either HF hospitalization or documented urgent clinic visit for HF with intravenous diuretics) within 12-months prior to baseline visit OR 2. Dyspnea on exertion and New York Heart Association (NYHA) ≥ class II symptoms AND AT LEAST ONE OF THE FOLLOWING CRITERIA: * Interstitial / pulmonary edema on prior chest imaging in the last year AND current loop diuretic use for heart failure * Elevated NT-proBNP in the last year defined as >400 pg/m for patients with no AF or paroxysmal AF, or >900 pg/ml for patients with ≥persistent AF * Mean pulmonary capillary wedge pressure (PCWP) ≥15 mm Hg or LVEDP ≥16 mm Hg at rest on cardiac catheterization OR pulmonary artery diastolic and wedge pressure (PADP) ≥15 mm Hg at rest on implantable monitor (e.g., CardioMEMs) * Echo criteria defined by ≥2 of: * LV wall thickness ≥ 12 mm * LV mass index (BSA indexed LVH): sex at birth male >115 g/m2, sex at birth female >95 g/m2 * Relative wall thickness ≥0.42 * E/e' ≥15 in sinus rhythm (or > 11 in the setting of atrial fibrillation) OR septal <7 cm/s or lateral e' <10cm/s * Tricuspid regurgitation (TR) velocity >2.8 m/s * Left atrial (LA) enlargement, defined by LA volume index >34 ml/m2 4. Patient is on stable guideline indicated HF medical therapy (Class I recommendations) for at least 30 days 5. Patient's average heart rate on baseline ambulatory electrocardiographic monitor is at least 5 bpm lower than their calculated personalized cardiac pacing rate (e.g. if a patient's personalized cardiac pacing rate is 70 bpm and their average heart rate on the ambulatory electrocardiographic monitor is less than or equal to 65 bpm the patient is eligible) 6. Patient is willing and able to adhere to the protocol (e.g., patient is able to ambulate independently at baseline). Exclusion Criteria: 1. Improved or recovered EF (i.e., prior LVEF<50%) 2. Patient has a previously implanted, currently implanted, or is intended to have implanted a cardiac implantable electronic device capable of delivering pacing (e.g., pacemaker, implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy (CRT)) 3. Current pregnancy (requirement for negative pregnancy test may vary by jurisdiction) 4. Average heart rate <50 bpm or symptomatic bradycardia 5. Acute coronary syndrome (including MI), cardiovascular surgery, or urgent percutaneous coronary intervention (PCI) within the 3 months prior to baseline visit or an elective PCI within 30 days prior to baseline visit. 6. Current acute decompensated HF requiring intravenous diuretics, vasodilators and/or inotropic drugs. 7. Severe obesity defined as BMI >45. 8. Persistent, long-standing persistent, or permanent atrial fibrillation (AF) with an average heart rate <50 bpm or evidence of ventricular pauses exceeding 6 seconds 9. Planned AF ablation 10. Infiltrative cardiomyopathies (e.g., amyloidosis, sarcoidosis) 11. Hypertrophic cardiomyopathies 12. Uncontrolled hypertension as defined by BP >160/100 mmHg on two measurements ≥15 minutes apart 13. End Stage Renal Disease (CKD 4 or greater) 14. More than moderate valvular disease (e.g. exclude patients with moderate severe or severe valvular disease) 15. Significant primary pulmonary disease on home oxygen 16. Known contraindication for a pacemaker implant 17. Advanced co-morbidity with life expectancy < 1 year 18. Patients who are currently enrolled in a potentially confounding drug or device trial during the course of the study. Co-enrollment in concurrent trials is only allowed when documented pre-approval is obtained from the Medtronic Study Manager. 19. Patient is a vulnerable adult (e.g. patient mentally incapable of giving consent).