A Study of 68Ga-Fibroblast Activation Protein Inhibitor (FAPI) Positron Emission Tomography in Heart Failure

HFpEF Group Inclusion:

* Patients aged ≥ 30 years old with exertional dyspnea (NYHA II and III) and LVEF ≥50%
* BMI ≥ 30
* New diagnosis of HFpEF based on RHC at baseline (elevated PCWP at rest and/or during exercise)

HFpEF Group Exclusion:

* Primary cardiomyopathy or pericardial disease or ≥ moderate valvular disease
* Dyspnea due to lung disease or CAD
* Severe anemia, liver, or renal disease
* Active cancer
* Systemic active inflammatory or autoimmune disease (e.g. rheumatoid arthritis, SLE, etc.)
* Recent hospitalization (\< 30 days) or coronary revascularization (\< 90 days)
* Patients already taking SGLT2i and/or GLP-1A
* Pregnant or breastfeeding
* Inability to tolerate supine position for the PET/CT or CMR scans.
* Contraindications for safe CMR scanning (e.g., uncontrolled claustrophobia, cochlear implant, implanted neural stimulator)
* Known gadolinium allergy
* Presence of implantable cardiac pacemaker or defibrillator or mechanical valve.

Cardiac Sarcoid Group Inclusion:

* Ambulatory patients aged ≥ 18 years old
* New referrals to the Sarcoid Clinic with a confirmed but untreated diagnosis of definite or probable CS based on 2014 HRS consensus (see Table 2)
* With a positive cardiac 18F-FDG PET scan within 30 days.

Cardiac Sarcoid Group Exclusion:

* Already on immunosuppressive therapy
* Pregnant or breastfeeding
* Severe liver or renal disease (estimated GFR \< 30 or dialysis-dependent)
* Recent coronary revascularization (\< 90 days)
* Active cancer
* Known gadolinium allergy
* Inability to tolerate supine position for the PET/CT or CMR scans.
* Contraindications for safe CMR scanning (e.g., uncontrolled claustrophobia, cochlear implant, implanted neural stimulator)
* Presence of implantable cardiac pacemaker or defibrillator or mechanical valve.

Healthy Controls Group Inclusion:

* Adults ≥ 30 years old
* No major chronic disease (cardiopulmonary, inflammatory, autoimmune, cancer, renal or liver impairment, etc.)
* No intake of relevant medication, defined as regular intake of at least one of the following: anticoagulants, antiplatelets, antihypertensive / diuretics, antidiabetics, antiarrhythmic, immunosuppressants, chemotherapy, antibiotics/antivirals/antifungals

Healthy Controls Group Exclusion:

* BMI ≥ 30
* Pregnant or breastfeeding
* Known gadolinium allergy
* Inability to tolerate supine position for the PET/CT or CMR scans.
* Contraindications for safe CMR scanning (e.g., uncontrolled claustrophobia, cochlear implant, implanted neural stimulator)