Understanding the different types of assessments, assessment tools, and findings acquired from these assessments, are all part of proper patient care in both acute and chronic emergency medicine management, in every realm of the term “PATIENT CARE”. One of the most important tools, in both the prehospital setting and long term care, is the 12 lead ECG, which just like any other tool, requires attention to detail, probably even more so than other tools. We have to know when to use it, why to use it, and be able to recognize the information given to use through its use.
ECGÂ INTERPRETATION IS MORE THAN A SKILL, IT’S AN ART!
It’s an art which requires never-ending practice and will never reach a limit. Â We will never know it all, and we will never be able to say, “I have seen it all”. Over the years we have seen providers and clinicians, in every setting and levelÂ of care, both being proficient and completely lacking ECG interpretation skill. Often, many clinicians, from Paramedics to Physicians, rely on the computerizedÂ ECG interpretation for proper patient care and management.
But how do we truly define “PROPER“?
Let’s discuss some scenarios…
This 93 year old male has been brought to the Emergency Department by a family memberÂ after complaining of suddenÂ spells. He is overall healthy considering the age, with minimal pertinent history and just takes daily vitamins, at least per the family. The following 12 lead ECG was obtainedThere appears to be sinus bradycardiaÂ with variant AVB (Atrioventricular Block), IVCD (both RBBB and LBBB morphologies) with Leftward frontal axis (Left Anterior Fascicular Block) at approximately -70 degrees (aVR is the most isoelectric lead perpendicular to aVL), aberrantly conducted impulses during the 2nd and 7th beats, with a QTc (using Bazett’s formula) of approximately 400 ms, not taking into consideration the slight afterdepolarizations which cause a false QT prolongation)
Because of the initial computerized ECG interpretation of “EXTREME TACHYCARDIA WITH WIDE COMPLEX”, lack of awareness (for professionalism’s sake) by the receiving physician, and chief complaint of dizziness, the patient was initially on the verge of receiving a full Amiodarone drip of 150 mg over 10 min, but thank goodness for compensatory hypertension. In this case, there were multiple things wrong with the computerized interpretation, and treatment to be followed.
- There Heart Rate is not 283 beats/min, but in the 30’s
- The QTc is not 1121 ms
- There is AV dissociation, with variant blocks throughout ED visit, from 1st degree to 3rd degree AVB
- Amiodarone is definitely not indicated in bradycardias or high degree AVBs
Click on the highlighted title for an Amiodarone breakdown,Â UNDERSTANDING AMIODARONEÂ Â One tool I use in these cases of bradycardia, is SPo2 monitoring. Remember, with every systole achieving arterial pressures, the Pulse Oximeter will provide a value and waveform. We are not focusing on oxygenation values right now, just the presence of an SPo2 pleth coinciding with each QRS on the cardiac monitor.
Conclusion to 1st case:
This patient was admitted to the cardiovascular unit, Â awaiting pacemaker placement.
Another example of why we should not solely rely on the computerized ECG interpretation:
There is a sinus rhythm with LVH, physiologic Leftward axis (aVF is the isoelectric lead perpendicular to Lead I) at approximately -10 degrees. No primary (ischemic) ST-T changes with normal R wave progression and QT prolongation.
The computerized ECG interpretation isÂ SINUS TACHYCARDIA WITH 2nd DEGREE AV BLOCK 2:1 AV CONDUCTION”
Â Does this mean that we will give Atropine or stand by pacing for the 2nd degree AVB? If you answer is NO, then you’re on the right track…
Now, in most instances, the computerized interpretation is accurate and useful:
Â While other times, it may not be as specific, depending on variations, most commonly movement and poor lead placement leading to Artifact:
Other causes of inaccurate computerized interpretation include:
- QRS width
- Intrinsic rate and irregularity
- ST segment and T wave morphology
This is taking into consideration that each system has an analysis algorithm, like the Physio-Control’s Lifepak 15, one of the most common cardiac monitors used prehospitally, which uses the Glasgow Analysis Algorithm, which gives us the computerized interpretations based on calculations and measurements of the recorded waves from parameters set by the creators.
Â Image obtained from Physio-Control
1.We should not base our ECG interpretation and our patient’s care and treatments solely on the computerized interpretation provided.
2. The computerized interpretation gives us a second opinion on cardiac electrical system analysis, and is not a confirmed statement.