The purpose of this study is to internally validate low-field Ex-CMR as a noninvasive tool for diagnosing, phenotyping, and risk stratifying HFpEF in patients with exertional dyspnea.

Inclusion Criteria:

1. Informed consent obtained

2. Three groups will be enrolled:

   1. HFpEF (cardiologist-adjudicated diagnosis as verified by PI, EF≥50%)
   2. Non-cardiac dyspnea (patients have dyspnea but were found on invasive exercise testing not to have HFpEF).
   3. Healthy volunteers with no history of dyspnea or effort intolerance.

Exclusion Criteria:

1. Contraindication for low-field CMR, as indicated in MRI safety screening checklist (Research Document #1)
2. Patient inability or unwillingness to undergo Ex-CMR
3. Cardiac implants, mechanical or biological valve, causing artifacts that compromise the quality of data
4. Hospitalization for heart failure in the preceding 30 days.
5. Large R-R interval variation, caused by frequent premature ventricular contractions or non-sinus rhythms such as persistent atrial fibrillation, which, in the opinion of the investigators, compromises the quality of data acquisition, image analysis and disrupts the consistency of the cohorts
6. Myocardial infarction or unstable angina pectoris
7. Planned coronary, carotid, or peripheral artery revascularization
8. Other causes of dyspnea as indicated in patients' medical history based upon the opinion of the PI, such as restrictive cardiomyopathy or infiltrative conditions (e.g., amyloidosis), hypertrophic obstructive cardiomyopathy, primary pulmonary arterial hypertension, more than moderate chronic obstructive pulmonary disease, right heart failure due to pulmonary disease, complex congenital heart disease, severe anemia, or more than moderate mitral or aortic heart valve disease).

Participants will be identified from Mayo Clinic Cardiac Cath lab appointment lists.