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Efficacy of the CMI Magnetocardiograph in Diagnosing Acute Coronary Syndromes in Patients Presenting With High Risk Unstable Angina.

This study has been completed.
CardioMag Imaging
Information provided by:
Mayo Clinic Identifier:
First received: September 12, 2005
Last updated: July 15, 2011
Last verified: July 2011
A magnetocardiograph (MCG) is a device capable of recording of magnetic fields arising from the electrical activity of the heart with traces similar to an electrocardiogram (ECG). This system was developed as a noninvasive, non-contact diagnostics of obstructive coronary artery disease (CAD), and especially of lack of oxygen in the heart as in a heart attack. The overall objective of this study is to demonstrate the efficacy of this MCG device for the detection and diagnosis of lack of oxygen of the heart in patients with chest pain.

Condition Intervention Phase
Myocardial Ischemia Device: Magnetocardiograph Phase 3

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Efficacy of the CMI Magnetocardiograph in Diagnosing Acute Coronary Syndromes in Patients Presenting With High Risk Unstable Angina as Defined by ACC/AHA Guidelines

Resource links provided by NLM:

Further study details as provided by Mayo Clinic:

Primary Outcome Measures:
  • 1. Determine the discriminatory ability of the scores derived from the MCG evaluation to discriminate between patients with versus without a clinical diagnosis of ACS at discharge. [ Time Frame: 1 year ]
  • 2. Compare the discriminatory ability of scores derived from the MCG, the troponin level, and the ECG results, separately or in combination, to discriminate between patients with without a diagnosis of ACS at discharge. [ Time Frame: 1 year ]

Secondary Outcome Measures:
  • 1. Evaluate the sensitivity of the MCG to detect an ultimate diagnosis of ACS, MI, CHF, or death at 1 month, 6 months, and 1 year following discharge. [ Time Frame: 1 year ]

Enrollment: 137
Study Start Date: August 2004
Study Completion Date: February 2008
Primary Completion Date: February 2008 (Final data collection date for primary outcome measure)
Intervention Details:
    Device: Magnetocardiograph
    MCG and ECG recordings sequentially at the four pre-defined bed positions and watches the real-time magnetocardiogram traces on the computer screen. At each position, nine sensors record MCG data, thus forming a 3 x 3 point grid square with point-to-point separation of 40 mm. The number of cardiac cycles recorded at each position should be adequate for signal averaging. Recording time per position is typically 90 seconds. At the end of 4 sequential recordings, raw, unfiltered MCG data are stored.
Detailed Description:

Coronary Artery Disease is the leading cause of death in the United States. The non invasive detection of Acute Coronary Syndromes (ACS's) remains a clinical challenge. Electrocardiogram (ECG) may only diagnose myocardial infarction in 50 % of the cases. Magnetocardiography is a new and noninvasive method capable of measuring and mapping the magnetic field that is generated during the cardiac cycle. The electric current is affected by ischemic damage, which in turn alters the magnetic field. The magnetic field is not affected by body tissues, unlike the surface current measurements in ECG.

Comparisons: The diagnostic accuracy of the CMI-Magnetocardiograph will be compared to that of the ECG in diagnosing High Risk Unstable Angina.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population

*ACC/AHA Guidelines for Unstable Angina: High Risk (≥1 of the following)


  • Accelerating tempo of ischemic symptoms in the last 48 hrs Pain
  • Prolonged, ongoing (>20 min) rest pain (resistant to treatment) Clinical findings
  • Pulmonary edema
  • New / ↑ MR murmur
  • S3 or new/ ↑ rales
  • Hypotension, brady -/tachycardia - Age>75y ECG
  • Angina at rest with transient ST changes >0.05 mV
  • New (L)BBB
  • Sustained VT Cardiac Markers
  • Markedly elevated troponin

Patients classified as having high-risk unstable angina at presentation in the ED will be approached for enrollment in the study.


Inclusion criteria:

  • Patients classified as having High Risk Unstable Angina according to the ACCIAHA guidelines.
  • Age ≥ 18 years.

Exclusion criteria:

  • Hemodynamically unstable patients.
  • Patients who just prior to or just after admission exhibit tachycardia with heart rates exceeding 150 bpm.
  • Patients with third degree AV Block.
  • Patients with pacemakers or internal cardiac defibrillators.
  • Patients who cannot lie in a supine position for the MCG examination.
  • Patients who refuse entry into the registry
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00169975

United States, Minnesota
Mayo Clinic
Rochester, Minnesota, United States, 55905
Sponsors and Collaborators
Mayo Clinic
CardioMag Imaging
Principal Investigator: Peter A. Smars, M.D. EM Mayo Clinic
  More Information

Responsible Party: Peter Smars, MD, Mayo Clinic Identifier: NCT00169975     History of Changes
Other Study ID Numbers: 738-04
Study First Received: September 12, 2005
Last Updated: July 15, 2011

Additional relevant MeSH terms:
Acute Coronary Syndrome
Myocardial Ischemia
Coronary Artery Disease
Angina, Unstable
Pathologic Processes
Heart Diseases
Cardiovascular Diseases
Vascular Diseases
Coronary Disease
Arterial Occlusive Diseases
Angina Pectoris
Chest Pain
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms processed this record on August 16, 2017