Diagnostic Utility of Exercise Cardiac Magnetic Resonance in the Assessment of Cardiac Dyspnea.

Inclusion Criteria: * Consecutive patients aged ≥18 years years with suspected cardiac dyspnea who are scheduled to undergo right heart catheterization as dictated by a comprehensive examination and echocardiography will be included for enrollment. Exclusion Criteria: * Age \<18 years * Pregnancy * Mechanical ventilation * Acute or chronic renal failure (creatinine clearance \<30 ml/min or requiring renal replacement therapy) * Inability to perform MRI (i.e. claustrophobia, severe obesity (\>150 kg), device incompatible with MRI) * Inability to exercise * Significant arrhythmia that precludes adequate ECG-gating for the MRI (i.e. atrial fibrillation with highly variable cycle lengths) * Prior heart or lung transplantation * Left ventricular systolic (ejection fraction \<50%) or diastolic failure (based on Framingham criteria for heart failure with preserved ejection fraction) * Significant left-sided valvular disease (≥moderate aortic stenosis, mitral stenosis, aortic regurgitation, mitral regurgitation) or prior valve surgery