Inclusion Criteria:

• Patients who meet all eligibility criteria and are randomized in the parent PRIMARY trial.
• For the ancillary biospecimen study, patients who are randomized to MVr in the parent trial.

Exclusion Criteria:

• Severe claustrophobia not controlled with sedation.
• Prior adverse reaction to gadolinium administration.
• Patients with an implantable subcutaneous cardioverter defibrillator and/or cardiac resynchronization therapy device with defibrillator may be excluded as they typically produce substantial artifacts on cardiac MRI making assessment very challenging.
• Known allergic reaction to adhesives or hydrogels or with family history of adhesive skin allergies (for patients undergoing rhythm monitoring).