REmodeling the Left Ventricle With Atrial Modulated Pacing

Inclusion Criteria:

Subject has had a market released dual chamber Medtronic Pacemaker with a Sleep function for at least 3 months
Subject is stable on current medications
Subject has dyspnea with exertion or diagnosed as NYHA Class II or III Heart Failure
Subject has had a prior Echo in past 6 months with: EF ≥ 50% and Diastolic volume <80 ml/m²
Subject has evidence of hypertrophy (indexed to body surface area: men 115 g/m², women 95 g/m² or indexed to height: men 49.2 g/m2.7, women 46.7 g/m2.7) or Relative Wall thickness >0.42, or Wall Thickness>1.2cm (posterior wall)
Subject is willing to sign and date the study Informed Consent Form (IC Form) - Subject is 18 years of age or older, or of legal age to give informed consent per local law
Subject is expected to remain available for follow-up visits

Exclusion Criteria:

Subject has permanent AF or AF noted on baseline interrogation rhythm strip
Subject has uncontrolled BP; (systolic pressure needs to be >100mmHg and <160mmHg on medications)
Subject has severe stenosis of the aortic or mitral valve, defined as valve area ≤1.0 cm² or severe regurgitation of the aortic or mitral valve
Subject has symptomatic Chronic Obstructive Pulmonary Disease (COPD) requiring oxygen
Subject's Pacemaker has less than 6 months of Pacemaker battery life
Subject had an aortic valve replacement (surgical or TAVR) procedure less than 9 months prior to enrollment
Subject's programmed upper rate limit is less than 100 bpm because of concerns of elevated pacing
Subject is unable or unwilling to perform the 6 Minute Walk Test at all scheduled study visits
Subject is currently enrolled or planning to enroll in a potentially confounding trial during the course of the study (co-enrollment in concurrent studies is only allowed when documented pre-approval is obtained from the Medtronic study manager)
Subject is pregnant
Subject meets any exclusion criteria required by local law
Subject's life expectancy is less than 12 weeks
Subject with medical condition that precludes the patient from participation in the opinion of the investigator
Subject has known coronary disease with Class II angina