Chieng et al1 should be congratulated for the pertinent article on the usefulness of prone electrocardiogram (ECG) in the evaluation of cardiac patients. After the outbreak of the COVID-19 pandemic in December 2019, numerous therapies have emerged for the treatment of acute distress respiratory syndrome (ADRS) associated with the infection. Prone ventilation has proven to significantly reduce mortality rates in patients with ADRS,2 and has been increasingly used in this population.
ECG in the prone position is usually recorded transposing to the back the location of the precordial electrodes. Chieng et al1 concluded that this anatomic mirror ECG can be “useful for ST-segment/T-wave abnormalities in limb leads, BBB detection, and rhythm monitoring” but “is unreliable for the detection of anterior myocardial injury” because the anatomic mirror leads obtained from the back are unpredictably different from the standard precordial leads recorded in the supine position.
Based on the classic concept of mirror-image ECG,3 we have recently presented a different method to register ECGs in patients in the prone position.4 According to the dipole theory, there is an antipodal area for each precordial point where an inverted ECG lead can be recorded. The position of these antipodal areas in the back goes up in a rough line from the left scapular line at the fifth intercostal level (mirror V1) to the right anterior axillary fold at the second intercostal level (mirror V6).
The mirror precordial leads obtained in this manner show low amplitude but are qualitatively similar (although inverted!) to the standard precordial leads.
We propose using mirror leads (M1-M6), which allows ST-segment change interpretation, as an alternative to recording the transposed posterior precordial leads (V1p-V6p) in the prone position, described by Chieng et al.1
Footnotes
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
References
- 1.Chieng D., Sugumar H., Kaye D., et al. Prone and supine 12-lead ECG comparisons: implications for cardiac assessment during prone ventilation for COVID-19. J Am Coll Cardiol EP. 2021;7(11):1348–1357. doi: 10.1016/j.jacep.2021.04.011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Guérin C., Reignier J., Richard J.C., et al. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013;368(23):2159–2168. doi: 10.1056/NEJMoa1214103. [DOI] [PubMed] [Google Scholar]
- 3.Kors J.A., van Herpen G. Mirror image electrocardiograms and additional electrocardiographic leads: new wine in old wineskins? J Electrocardiol. 2008;41(3):245–250. doi: 10.1016/j.jelectrocard.2008.02.003. [DOI] [PubMed] [Google Scholar]
- 4.Cobos Gil M.A., Diz J., Islas F. A new method for ECG recording in the prone position. Eur Heart J. 2021;42(Supplement 1) ehab724.0308. [Google Scholar]