Medical Policies - Radiology

Fetal Magnetocardiography (fMCG)


Effective Date:10-01-2018



Fetal Magnetocardiography (fMCG) is considered experimental, investigational and/or unproven for all indications including but not limited to, the evaluation of cardiac conduction and rhythm in fetuses with known or suspected conduction system abnormalities.


One to two percent of pregnancies may be complicated by fetal arrhythmias which may potentially compromise fetal health. (1) The fetal heart’s conduction system is functionally mature by 16 weeks of gestation, and produces a regular rhythm and rate. (1) Early detection and diagnosis of fetal arrhythmias may increase the possibility for appropriate therapeutic interventions, reducing fetal complications.

Fetal magnetocardiography (fMCG) is a non-invasive technique able to monitor the spontaneous electrophysiological activity of the fetal heart. Interest in fetal magnetocardiography exists due to the fact that electrical signals are distorted by the varying resistive layers between the signal source and the skin. (3) These barriers do not distort magnetic fields. This provides an advantage for fetal magnetocardiography over electrocardiography.

The technology that allows the model 621/624 Biomagnetometer to detect magnetic fields created by the electrical activity of the heart uses superconducting quantum interference devices (SQUIDs) and superconducting pick up coils. The process of detecting the magnetic fields can be used to create a magnetocardiogram that looks similar to an electrocardiogram (ECG). Because continuous recordings can be performed it may be possible to detect and evaluate conduction abnormalities in fetuses. At this time, this process requires a magnetically shielded environment.

Regulatory Status

The U. S. Food and Drug Administration (FDA) cleared the Model 621/624 Biomagnetometer (Tristan Technologies, Inc.) a magnetocardiograph, through the 510(k) processed on March 15, 2016. The Tristan Technologies Model 621/624 Biomagnetometer is intended for use as a tool that non-invasively measures and displays the magnetic signals produced by the electric currents in the heart of human beings of any age or in the heart of a fetus in utero. (2)


This medical policy was created in July 2017 and is based on published scientific literature from MedLine database searches. The most recent search was completed in July 2018.

In an article Hrtankova et al. (2015) provided an overview, based on analysis of a literature review, of fetal magnetocardiography (fMCG) as a new diagnostic method. The authors note that compared to cardiotocography and fetal electrocardiography, the fMCG is a more effective method with a higher resolution. The signal obtained from the fetal heart is sufficiently precise and the quality allows an assessment of PQRST complex alterations, and to detect fetal arrhythmia. The authors go on to note according to the latest theories, fetal heart rate (FHR) variability is a possible indicator of fetal status and enables the study of the fetal autonomic nervous system indirectly. Fetal magnetocardiography is an experimental method that requires expensive equipment. It is yet to be shown, if this method will get any application in clinical practice. (4)

In a study by Fehlert et al. (2016) to evaluate a hypothesis that gestational diabetes mellitus (GDM) may also impact on the fetal autonomic nervous system under metabolic stress like an oral glucose tolerance test (OGTT), 13 pregnant women with GDM and 36 pregnant women with normal glucose tolerance were examined. All women underwent an OGTT during which fetal magnetocardiography (fMCG) was recorded three times. The heart rate variability (HRV) of mothers and fetuses during a three-point OGTT using fMCG was measured. The authors note in their results no significant differences of maternal HRV were noted. However, the HRV in fetuses of mothers with GDM differed from those in the metabolically healthy group regarding standard deviation normal to normal beat (SDNN) (P = 0.012), low-frequency band (P = 0.008) and high-frequency band (P = 0.031). These HRV parameters exhibit a decrease only in GDM fetuses during the second hour of the OGTT. Conclusions noted by the authors included; disturbances in maternal glucose metabolism might not only impact on the central nervous system of the fetus but may also affect the fetal autonomic nervous system. (5)

Cuneo et al., evaluated 17 fetuses with complete heart block (CHB) caused by immune-mediated damage to a normal conduction system (isoimmune, n = 8) or a congenitally malformed conduction system associated with left atrial isomerism (LAI, n = 9). Fetal atrial and ventricular beat rates were compared before and after transplacental terbutaline treatment by fetal echocardiography. While receiving terbutaline, 9 of the 17 fetuses underwent fetal magnetocardiography (fMCG) to assess maternal heart rate (HR) and rhythm, patterns of fetal HR acceleration, and correlation between fetal atrial and ventricular accelerations (i.e., atrioventricular [AV] correlation). The authors noted that terbutaline did not restore the normal coordinated response between atrial and ventricular accelerations in isoimmune or LAI CHB. They concluded, the pathophysiologic heterogeneity of CHB is reflected in the differing effect of terbutaline on the atrial and ventricular pacemaker(s) and varying patterns of HR acceleration. However, regardless of the cause of CHB, terbutaline augments HR but not AV correlation, suggesting that its effects are determined by the conduction system defect rather than the autonomic control of the developing heart. (6)

Summary of Evidence

Available literature is comprised of review articles and studies with small sample sizes. The evidence is insufficient to determine the effects of the technology on health outcomes at this time.


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The following codes may be applicable to this Medical policy and may not be all inclusive.

CPT Codes

0475T, 0476T, 0477T, 0478T



ICD-9 Diagnosis Codes

Refer to the ICD-9-CM manual

ICD-9 Procedure Codes

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ICD-10 Diagnosis Codes

Refer to the ICD-10-CM manual

ICD-10 Procedure Codes

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Medicare Coverage:

The information contained in this section is for informational purposes only. HCSC makes no representation as to the accuracy of this information. It is not to be used for claims adjudication for HCSC Plans.

The Centers for Medicare and Medicaid Services (CMS) does not have a national Medicare coverage position. Coverage may be subject to local carrier discretion.

A national coverage position for Medicare may have been developed since this medical policy document was written. See Medicare's National Coverage at <>.


1. Levine J, et al. Overview of the general approach to diagnosis and treatment of fetal arrhythmias. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. Available at: <> (accessed 2017 February 17).

2. Food and Drug Administration, Model 621/624 Biomagnetometer (K151135) March 15, 2016. Available at:<> (accessed 2017 February 16).

3. Product information re: Biomagnetism and fetal magnetocardiography. Available at:<> (accessed 2017 February 22).

4. Hrtánková M, Biringer K, Siváková J, et al. [Fetal magnetocardiography: a promising way to diagnose fetal arrhytmia and to study fetal heart rate variability?]. Ceska Gynekol. Jan 2015; 80(1):58-63. PMID 25723081

5. Fehlert E, Willmann K, Fritsche L, et al. Gestational diabetes alters the fetal heart rate variability during an oral glucose tolerance test: a fetal magnetocardiography study. BJOG. Dec 28, 2016. PMID 28029217

6. Cuneo BF1, Zhao H, Strasburger JF, et al. Atrial and ventricular rate response and patterns of heart rate acceleration during maternal-fetal terbutaline treatment of fetal complete heart block. Am J Cardiol. Aug 15, 2007; 100(4):661-5. PMID 17697825

Policy History:

10/1/2018 Reviewed. No changes.
7/1/2017 New medical document. Fetal Magnetocardiography (fMCG) is considered experimental, investigational and/or unproven for all indications including but not limited to, in the evaluation of cardiac conduction and rhythm in fetuses with known or suspected conduction system abnormalities.

Archived Document(s):

Title:Effective Date:End Date:
Fetal Magnetocardiography (fMCG)07-01-201709-30-2018
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