Purpose: To show early feasibility of magnetocardiography (MCG) to identify coronary Cardiac positron emission tomography (PET) is the preferred non-invasive tests to assess for CAV and incorporation of quantitative myocardial blood flow (MBF) assessment improves diagnostic accuracy. Based on ISHLT criteria, the following have been proposed for diagnosis of CAV by PET:

Diagnosing CAV by PET with quantitative myocardial blood flow (MBF) 3 PET CAV 0: Normal perfusion with normal global stress (> 1.7 mL/min/g)

PET CAV 1: Normal perfusion with abnormal global stress MBF (<1.7 mL/min/g and ejection fraction >45%) OR Single vessel perfusion defect with normal global stress MBF.

PET CAV 2/3: Normal perfusion with abnormal global stress MBF (<1.7 mL/min/g) and ejection fraction < 45% OR Single vessel perfusion defect with abnormal global stress MBF (<1.7 mL/min/g) OR Multivessel perfusion defects

With these diagnostic criteria, PET CAV 0 has been shown to have a high negative predictive value for moderate to severe CAV by invasive coronary angiography, and PET CAV 2/3 has been shown to have a high positive predictive value for moderate to severe CAV and is associated with adverse events.

This study further examines the feasibility of MCG in identifying CAV in adult heart transplant recipients and compares those results to the current non-invasive standard using PET CAV scores. This will help determine whether MCG is a potential test for regular surveillance of CAV in transplant recipients.

Inclusion Criteria:

• ≥ 18 years of age at the time of enrollment

Willing to provide written informed consent

Completed cardiac PET within the last 2 weeks

No changes to medication or intervention since the PET was completed

Exclusion Criteria:

• Patients unable to fit into device

Patients unable to lie supine for 5 minutes

Patients with implanted ferromagnetic objects above the costal margin of the rib cage (implanted pacemakers, cardioverter/defibrillators, infusion pumps, and/or neuro stimulators).

NOTE: Sternotomy wires stents are acceptable

Implanted pacemakers or cardioverter/defibrillators

Implanted infusion pumps and/or neuro stimulators

Severe claustrophobia

Heart transplant recipients are susceptible to developing coronary allograft vasculopathy (CAV), a disease that causes blockages in the arteries of the transplanted heart. CAV often progresses without symptoms, and transplant recipients undergo regular surveillance to detect CAV. Current tests used to detect CAV, such as invasive coronary angiography (ICA) and intravascular ultrasound (US) have clear limitations; in addition to being invasive with risk of complications, they are also expensive, time consuming, and require iodinated contrast, a concern in a population with high rates of kidney dysfunction. In addition, these tests may not be able to detect CAV in its early stages. Additionally, the diagnosis of CAV remains a challenge as angiography, the standard method for detecting focal plaques, lacks sensitivity in detecting CAV, and intravascular ultrasonography, a more sensitive method, lacks the ability to evaluate the entirety of the coronary arteries.