Welcome to 'Monitor Corner' - Griddle Approach to Rhythms
Words of the Wise
"The challenge.... is to keep a sense of balance, a sense of direction, a sense of selectivity in knowing what to exclude rather than what to include, with the clinician in mind." [The Disorders of Cardiac Rhythm 2e - Leo Schamroth 1980]
"Who needs logic anyway - apart from a handful of armchair scholars who will reduce it to a well chewed pap of logical schemas" [The Night Watch - Sergei Lukyanenko 2012]
"This book is about information, imperfection, uncertainty, and the future of medicine. ... Much of the (core curriculum information taught .... during medical school) .... could be looked up in a book or found by a single click on the Web."
"The information that was missing was what to do with information - especially when the data was imperfect, incomplete or uncertain."
"My medical education had taught me plenty of facts, but little about the spaces that live between facts." [The Laws of Medicine - Siddhartha Mukherjee 2015]
"ECG learning is slowly but surely going the physical examination way. Too bad that this is not being adequately addressed at the residency level. There is nothing more basic and yet more fundamental than [the] ECG in all of cardiology - essentially the first stepping stone. Problem is it is too often either feared, avoided or trivialized (and relegated to a computer algorithm)" [Dr. Sumit Som Cardiologist April 9th 2017]
Instant Diagnosis or Griddle Analysis?
I remain fascinated by the ECG and it's ability to reveal graphically the beats of the heart. Becoming competent in ECG evaluation took me a long time, and involved looking at and reporting on hundreds of tracings. I developed what I now refer to as the Griddle Analysis approach, which I will use in this series of rhythm strips called Monitor Corner.
The challenges that I still face despite many years of interpreting and teaching ECGs are
Zones of uncertainty
Ambiguity of diagnosis
The 'over-reading trap'
Sin of diagnostic greed i.e. trying to explain every deflection
Knowing when to do an in-depth interpretation or settle for a quick look evaluation.
One of the advantages of teaching, and of many internet sites on ECGs, is that they require or provide an in-depth evaluation and explanation.
I have observed that (in some Emergency Departments in Melbourne) there has been a decreased emphasis on detailed and careful analysis of ECGs, and acceptance of superficial or 'good enough' interpretations. That may not matter if the Cardiology Unit will be checking each ECG, or if you trust computer analysis of the ECG.
Computers are good at measuring rates and intervals, but have their limitations as discussed by these two cardiologists:
"There are typical patterns of computer ECG mistakes. A common one is when the computer tries to interpret poor-quality tracings. Baseline artifact or poor electrode contact should be a warning not to accept the machine read. Irregular rhythms are another area in which the computer struggles" [ECG-Reading: Don't Cede Control to the Machines - Medscape Emergency Medicine April 6th 2017 John Mandrola]
"This problem is getting worse. When I was reading for a hospital, I changed about 20% of the computer reads. Over-diagnosing is a bigger problem. Some programs read LVH on what look to me like normal tracings. Others call anterior and inferior infarcts on the basis of poor r wave progression and tiny q waves. And yet, the computers have a terrible time diagnosing arrhythmias. This is a big problem, leading to misdiagnosis, unnecessary consults, and needless anxiety in otherwise healthy patients." [Dr. David Kabel Cardiologist April 8th 2017]
But what to do if you find yourself on your own in a hospital with limited resources, looking at an ECG that you think you are familiar with or else looks a 'little different' but nothing like other dangerous patterns you have seen in books or on the internet?
You can send a copy of the ECG by smart phone to a Cardiology Registrar for an opinion. That is a reasonable approach, although there are some critics of this:
"I think it is an abomination to read a 12 lead EKG on a smart phone screen, especially when the question is whether or not this is a STEMI. (this may be a consequence of my worsening presbyopia). It's usually because the ER can't or won't download the EKG to the EHR, or can't figure out how to scan and e-mail the EKG. I have read hundreds of crappy faxed EKG's, however." [Dr George Palk Cardiologist 12th April 2017]
My views are
1. You use all available resources that are appropriate to the situation - computer, experienced Emergency Department doctor or nurse, Cardiologist etc.
2. You have prepared for this situation by developing a systematic and thorough approach to looking at, and describing, ECG waves and intervals and rates - Griddle Analysis.
What is a griddle? This is a wire-bottomed sieve used by miners to sift out the most important part of their extracted material.
And what does Griddle Analysis of ECGs or Rhythm Strips involve:
Describing the changes. This can be a challenge: level of discussion/using the correct terminology/selecting what to describe or discuss/nuances of meaning
Laddergram analysis when appropriate
In other words: look/describe/measure/think to reach a diagnosis
Who is Monitor Corner for? It is for persons interested in arrhythmias and in sharpening their diagnostic skills and willing to spend some time in looking and analyzing/willing to spend time touching & handling 'hard copy'
The rhythm strips and ECGs are from real cases :- sometimes there is no clinical information, the details of other cases have been recalled from memory, some details are from notes that I made.
Why these strips? :- Interesting/instructive/challenging/aesthetic/range of complexity/common patterns
Some tracings have a poetry in the pattern of their rhythm or an elegance in the mechanism
So - Welcome to Monitor Corner!