Mayo Clinic
To evaluate the effect of CS reducer implantation in patients with HFPEF and CMD on myocardial ischemia, measured by stress myocardial perfusion using cardiovascular magnetic resonance (CMR)
Inclusion Criteria: * Age ≥18 * Enrollment in main CS-reducer HFPEF study IRB# 25-002292 Exclusion Criteria: * Metal implants that are not suitable for MRI * Inability or unwillingness of individual to give written informed consent.
Patients will consent to undergo a 50-minute non-invasive stress perfusion CMR.