Fetal Magnetocardiography for the Diagnosis of Fetal Dysrhythmias: Single-Center Experience Over 8 Years.


Fetal Magnetocardiography for the Diagnosis of Fetal Dysrhythmias: Single-Center Experience Over 8 Years.

Bolin EH, Whittington JR, Mehl ST, Escalona-Vargas D, Eswaran H.JACC Clin Electrophysiol. 2022 Sep;8(9):1161-1163. doi: 10.1016/j.jacep.2022.05.011. Epub 2022 Jul 27.PMID: 35907757 

Take home points:

  • Fetal magnetocardiography (fMCG) by superconducting quantum inference device technology has shown promise in its ability to diagnose dysrhythmias and channelopathies in utero.
  • fMCG augments, but does not replace, fetal echocardiography for the evaluation of fetal dysrhythmias. The authors found fMCG to be most useful for discriminating between wide and narrow complex rhythms.
Manoj Gupta

Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch.


From January 1, 2013, to December 31, 2020, there were 66 women referred for fMCG because of suspected fetal dysrhythmia at an average gestational age of 31.0 ± 4.5 weeks. We classified rhythm disturbances into 4 categories: sinus rhythm (n = 11; 17%); ectopy or intermittent tachycardia <50% of time monitored (n = 37; 56%); sustained tachydysrhythmia ≥50% of time (n = 12; 18%); and bradycardia (n = 6; 9%). Of those with sustained tachycardias, 8 had narrow complexes and the other 4 had wide complexes

It was less useful for differentiating among various narrow complex tachycardias, mainly because of fMCG’s inability to consistently display beat-to-beat P-waves at earlier gestational ages. 2 Additionally, all fetuses with evolving or complete heart block were readily diagnosed with fetal echocardiography, and fMCG provided confirmation but did not change management.


With increasing rates of prenatal diagnosis of heart disease in the United States, fetal arrhythmias may be diagnosed earlier in gestation, possibly resulting in more severe arrhythmias being identified prior to what would otherwise have resulted in fetal demise.

This seems to have been authors experience, because one-third of the fetal tachycardias they encountered were wide complex.

With continued refinements in superconducting quantum inference device technology and concomitant decreases in cost, more groups may consider developing their own program to meet growing needs.