Relationship Between LINQ™ Subcutaneous Impedance and Right-sided Hemodynamic Measurements

Inclusion Criteria: * Patients meeting at least 1 of 3 criteria will be included in the study: * Patients with symptomatic systolic or diastolic heart failure who in the clinician's judgment have a high likelihood of undergoing serial right heart catheterizations to aid in clinical management of their heart failure * Patients with dyspnea on exertion in whom exercise hemodynamics is indicated to diagnose diastolic dysfunction * Patients who have or will be implanted with a pulmonary artery pressure monitor * Patient is 18 years of age or older * Patient (or patient's legally authorized representative) is willing and able to provide written informed consent * Patient is willing and able to comply with the protocol, including follow-up visits and Carelink transmissions. Exclusion Criteria: * Patient has an existing Medtronic implantable cardiac device * Patient has a left ventricular assist device (LVAD) * Patient is pregnant (all females of child-bearing potential must have a negative pregnancy test within 1 week of enrollment) * Patient is enrolled in another study that could confound the results of this study, without documented pre-approval from a Medtronic study manager