Study was defunded.

This is a multicenter, prospective trial to measure the test performance characteristics of the Magnetocardiography (MCG) CardioFlux cardiac diagnostic system in detecting clinically significant coronary artery obstruction in patients with symptoms of suspected acute coronary syndrome or who present with a failed stress test with the intention of treat with cardiac catheterization.

This is a multicenter, prospective clinical trial studying the utility and accuracy of magnetocardiography (MCG) in identifying critical coronary artery obstruction responsible for myocardial ischemia. The study will enroll up to 1500 patients at high risk for coronary artery disease (CAD) who have been referred for cardiac catheterization. These patients will be recruited from an inpatient service post admission for chest pain or anginal equivalent or from a cohort of symptomatic patients who have failed outpatient stress testing. If they meet other stated inclusion criteria, they will have a 2 minute MCG scan prior to their cardiac catheterization. For comparative purposes, the first 300 patients will have an electrocardiogram (ECG) performed within 60 minutes of this initial scan.

After an enrolled study subject has had their catheterization procedure, the results of the catheterization will be reviewed by one of the study's primary investigators. If the subject has had a percutaneous coronary intervention (PCI), a second MCG scan will be performed prior to their discharge. The MCG scans will be interpreted by 3 physicians trained to read these images and blinded to all clinical information regarding study subjects.

The initial MCG scan will be evaluated for its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy in detecting myocardial ischemia and critical coronary stenosis based on angiographic imaging, fractional flow reserve (FFR), or instant wave-free ratio (iFR) measurements, as applicable. The same statistical analysis will be performed for the ECGs performed on each of the applicable study subjects. When performed, the second MCG will be evaluated for any abnormalities after revascularization. These results will be used to determine the value of post-PCI MCG to predict 30 day and 180 day major adverse cardiac events (MACE)-specifically myocardial infarction or stroke, need for revascularization, or cardiac related death.

Inclusion Criteria:

• Age ≥ 18 years of age at the time of enrollment.
• Patient presenting acutely with signs and symptoms suggestive of Acute Coronary Syndrome (ACS) and in the opinion of the treating physician and based on best clinical assessment that a cardiac catheterization will be performed; or, had a positive stress test and is scheduled for cardiac catheterization.
• Patient's ability to lay supine for five minutes.

Exclusion Criteria:

• Age < 18 years of age
• Patients unable to fit into device
• Unable to transfer to device gantry
• Positive response on magnetocardiography (MCG) prescreening form
• Patients with claustrophobia or unable to lie supine for five minutes
• Pregnant women
• Poor candidate for follow-up (e.g. no access to phone)
• Repeat participants
• Prisoners
• Acute STEMI or hemodynamically unstable patients (Mean Arterial Pressure ≤ 65, Respiratory Rate ≥24, Heart Rate ≥105 bpm, Temperature>38.1 or <34 degrees Celsius, O2 Saturation<90% despite oxygen therapy).
• Do not resuscitate order (DNR)
• Unable to have a cardiac catheterization secondary to dye, allergy, creatinine clearance, can't obtain access, etc.

This research study will enroll patients who will undergo cardiac catheterization because of symptoms and risk factors suggestive of acute coronary syndrome, and high risk patients presenting for cardiac catheterization due to an abnormal stress test. Patients meeting these criteria, and over the age of 18 years and all genders will be candidates.

There is no plan to make individual patient data (IPD) available to researchers not affiliated with the centers enrolling patients within this trial.