Insertable Cardiac Monitor for Primary Atrial Fibrillation Detection in High-Risk Heart Failure Patients

Inclusion Criteria: * Male and female patients more than 18 years of age (no upper age limit) * HF exacerbation requiring initiation or augmentation of decongestive therapy in a hospital setting (hospitalization or emergency department visit) during the past 24 calendar months prior to consent date OR current treatment with loop-diuretics (furosemide, bumetanide, or torsemide). * LVEF \> 35% on a cardiac imaging study (echocardiogram, nuclear imaging, cardiac magnetic resonance imaging) performed during the past 24 calendar months prior to consent date * One or more FDA-approved indications for an Abbott ICM (unexplained symptoms such as: dizziness, palpitations, chest pain, syncope, and shortness of breath, as well as patients who are at risk for cardiac arrhythmias). * Willing to undergo an Abbott ICM implant and agree to remote ICM monitoring. Exclusion Criteria: * Existing implantable cardioverter defibrillator (ICD), biventricular ICD, implantable cardiac monitor or pacemaker. * Known or documented history AF or atrial flutter any time in past. * Has had a heart transplant * Participation in other clinical trials (observational registries are allowed with approval from the Coordination Center) * Unable or unwilling to cooperate with the protocol * Unable or unwilling to sign the consent for participation