by Carolyn Thomas ♥ @HeartSisters
When you’ve had as many 12-lead ECG checks as I’ve had performed through the years since my coronary heart assault, you too might marvel at how swiftly the nurse or paramedic or Stress Take a look at Clinic tech can slap these sticky electrode patches onto your chest, legs and arms. Having noticed many individuals slapping patches on me, I usually marvel: how do they know in the event that they’re attaching these electrocardiogram patches onto the precise anatomical locations? .
An electrocardiogram measures electrical exercise of the center. ECG and EKG are abbreviations for a similar take a look at (EKG comes from the unique German, “elektrokardiogramm“). Mainly, there are three steps in performing this take a look at:
getting ready the affected person and their pores and skin
correct electrode placement (12 leads, calculated utilizing 10 electrodes hooked up to small, sticky patches: six positioned on the chest, one on every leg and arm)
checking the electrocardiograph settings and different gear required
It seems, sadly, that not all people excels in Step #2.
Research recommend that mis-positioning of ECG electrodes might have an effect on as much as 4 per cent of sufferers. That statistic may appear puny – till you keep in mind that, within the U.S. for instance, it covers a number of hundred thousand out of the 40 million ECGs recorded yearly. The disturbing conclusion of researchers: “The commonest technical components for floor electrode mis-positioning are carelessness or haste.”(1)
It’s simple to think about then, a crowded Emergency Division on a crazy-busy evening. It may be distracting even for expert staffers attempting to rigorously apply ECG electrodes to exactly appropriate physique factors. I’m guessing {that a} much less skilled healthcare skilled could possibly be much more distracted.
Two bits of ECG TRIVIA:
in a overview of Google Pictures of human torsos with ECG leads, the one photographs accessible had been of white males (Yep, see picture under*) and worse, the bulk confirmed incorrect lead placement.(2)
inaccurately positioned ECG electrodes are apparently most frequently seen in hospital Intensive Care Models.
Research on this difficulty usually view the most important drawback as false constructive outcomes (a misplaced electrode will NOT present normal-looking outcomes, so could also be misinterpreted as one thing fallacious with this specific coronary heart – not with the talents of the individual inserting the ECG leads). So a few of these sufferers, regardless of no coronary coronary heart illness, may have false constructive take a look at outcomes. This may be an costly mistake leading to additional cardiac checks and procedures. Contemplate that the nationwide gross cost within the U.S. for a cardiac stress take a look at can vary from $1,200 to $11,700.(3) Some sufferers have even been referred to the cardiac cath lab for costlier and extra invasive (and pointless) angiography procedures – primarily based on false positives.
Right here’s an instance of how even one mis-positioned ECG lead can distort your take a look at end result, from Dr. Stephen Smith, an Emergency doctor who teaches Emergency Medication on the College of Minnesota, however extra importantly, he and his group educate others all about ECGs. He recognized improper placement of 1 electrode after he seen a pulse tapping artifact (interference) on this ECG of a 60-year previous man with chest ache who got here to his Emergency Division.
“That is when an ECG electrode (on this case, within the left leg lead) is positioned close to an artery and is affected both by the mechanical motion of the artery, or presumably by {the electrical} conduction of the blood within the artery.”
After Dr. Smith requested his tech to maneuver that electrode barely, the artifact disappeared.
However think about this: even with appropriately positioned ECG electrodes, it may be difficult for a lot of physicians to accurately interpret the outcomes of your ECG (except Dr. Smith works in your hospital). The accuracy of doctor interpretation of ECGs could be surprisingly low.(4)
Dr. David Cook dinner, lead writer of a 2020 examine on doctor accuracy in decoding ECGs, concluded in his group’s overview of 78 printed research that on common, solely half of all ECGs are precisely interpreted, with medical college students having the bottom accuracy and – not surprisingly – cardiologists having the best accuracy at 75 per cent. When Yale heart specialist Dr. Harlan Krumholz reviewed this report for the New England Journal of Medication’s Journal Watch, he wrote:
“This sobering examine stories low accuracy within the interpretation of electrocardiograms throughout a variety of teams. Cardiologists did greatest, however nonetheless had a excessive prevalence of errors. And coaching had solely a modest impact within the research.”
That’s sobering certainly, particularly in the event you’re a coronary heart affected person like me whose coronary heart assault was misdiagnosed as acid reflux disease after my ECG was interpreted by an Emergency Division doctor as “regular”. That was proper earlier than he despatched me dwelling, feeling horribly embarrassed as a result of I’d simply made a fuss over“nothing”.
Nicely, nothing besides a myocardial infarction. . .
So coronary heart sufferers begin off with no less than two necessary questions for the medical occupation right here:
Are my 12-lead ECG electrodes positioned the place they need to be?
Does the individual decoding my ECG know learn how to precisely interpret this take a look at ?
Right here’s extra on CHEST electrode placement (in the event you’re a person)*
In ladies, leads V3-V6 needs to be positioned underneath your left breast. Nipples shouldn’t be used as reference factors in inserting electrodes on males or ladies as a result of – as everyone knows – nipple places differ a lot from individual to individual. Common Electrical Healthcare (which manufactures ECG gear) suggests in its report known as ECG Finest Practices for ECG Placement on Girls that not solely can anatomical variations complicate appropriate ECG placement on ladies in comparison with our male counterparts, however“fears or embarrassment about exposing feminine sufferers’ breast tissue can improve errors in ECG lead placement.” You need to lie as nonetheless and as quietly as potential to assist forestall miscellaneous “artifact” (interference) throughout your process. Cell telephones and your different non-essential gadgets needs to be positioned effectively away from you. Any medical indicators through the take a look at (e.g. chest ache) needs to be recorded by the individual doing all your ECG. Your privateness and dignity needs to be protected by draping you with a sheet to reduce publicity.
The 4 arm and leg placements of ECG electrodes have some wiggle room. Within the arms, an electrode could be positioned anyplace between the shoulder and elbow on both sides (though some sources specify wrists); within the legs, anyplace under the torso and above the ankle on both sides (though some sources specify ankles).
What I additionally marvel about, apart from acceptable electrode placement, are the false destructive ECGs (like my first one in Emergency) which can be misinterpreted as “regular” – growing the harmful threat of that ECG (like my first one) leading to a dismissed coronary heart assault. Personally, that is much more worrisome to me (and arguably extra harmful!) than being referred for an pointless stress take a look at primarily based on false positives.
I wrote right here about this hazard in a tragically true instance of dueling hospital physicians who couldn’t agree on the interpretation of a affected person’s ECG. On this case, the lethal tragedy was the preventable loss of life of a 70-year previous lady who arrived at Emergency with textbook cardiac signs she’d been experiencing for 5 days. She died after ready 2 1/2 hours in that Emergency Division whereas Emergency physicians argued with cardiologists about whether or not she was sick sufficient to deal with. This horrific instance is a case examine described by Emergency doctor Dr. Pendell Myers of Charlotte, NC, printed on Dr. Stephen Smith’s ECG weblog (together with skilled evaluation of this type of ‘what went fallacious?’ cardiac case).
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1. Rehman M, Rehman NU. “Precordial ECG Lead Mis-positioning: Its Incidence and Estimated Value to Healthcare”. Cureus. 2020 Jul 7;12(7)
2. Walsh B, Smith SW, Sifford D, et al. “Examples of precordial 12-lead electrocardiogram lead placement discovered on Google photographs are sometimes incorrect and lack gender and racial range.” Supply.
3. New Selection Well being: “Cardiovascular stress take a look at value and process info.” Might 2019
4. Cook dinner DA et al. “Accuracy of Physicians’ Electrocardiogram Interpretations”. JAMA Intern Med. 2020; 180(11):1461–14
ECG photographs courtesy of Cables and Sensors and GE Healthcare; different assets: Mayo Clinic, Medline Plus, Dr. Smith’s ECG Weblog, Emergency Medication Circumstances
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Q: How would you describe your individual ECG/EKG take a look at experiences?
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ANOTHER NOTE FROM CAROLYN: I wrote way more about cardiac analysis and misdiagnosis in my e book, A Lady’s Information to Dwelling with Coronary heart Illness (Johns Hopkins College Press). You possibly can ask for it at your native library or favorite bookshop (please help your native unbiased booksellers) or order it on-line (paperback, hardcover or e-book) at Amazon – or order it instantly from my writer (use their code HTWN to save lots of 30% off the record worth).
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See additionally:
When you’re a closet ECG nerd, eager on studying extra about these mysterious ECG squiggles, you would possibly take a look at the next hyperlinks:
– Emergency Medication Circumstances – “Misdiagnosis from Lead Misplacement, Artifact and Lead Reversal” by Toronto Emergency doctor Dr. Jesse McLaren, March 2022 (scroll right down to learn the comply with up explanations of plenty of case quizzes)
– Life within the Quick Lane: a 5-part ECG Fundamentals video displays by Dr. Theo Sklavos and Dr. William Wang – meant for medical/nursing/paramedicine college students – plus any skilled docs who want a superb refresher on decoding ECGs.
– Nearly any web page on Dr. Stephen Smith’s ECG weblog. That is the place individuals who love electrocardiograms come to hang around with different specialists. Some describe themselves as ECG hobbyists. I solely hope to have an ECG hobbyist doing my subsequent ECG. . .