Phenomenal feedback from Senior A&E Clinicians on The 'Subtle ACS & Mimics' ECG Workshop – the niche 2-day course on Subtle ACS (March 2025)
Despite being around for over 135 years, ECG remains the first line of investigation in cardiac illnesses.
It is likely that ECGs will continue to have the same relevance for the next 30-40 years, which is the duration of our careers.
Some diagnosis can be made only from ECGs (Eg: Abnormalities of Intervals & Rhythms, Pre-excitation, AV blocks, Subtle ischaemia etc).
There is no formal system of ECG reporting by experts (unlike for Xrays, CT scans etc).
The next line of investigation is usually difficult to obtain in ED (Eg: Echo, CAG, Holter, EP study).
Life altering decisions often need to be made immediately based on ECGs.
While we generally don't think about it, ED doctors see the most number of ECGs per shift across all specialities, arguably even more than Cardiology as well. This is because a significant percentage of all ED patients gets an ECG at some point.
ED doctors are more dependent on ECGs than even Cardiologists.
There are multiple reasons for this- the most important being that we make patient disposition decisions based on ECGs. And we usually have limited access to the next line of investigations like Echocardiography, Coronary angiogram, Holter, Electrophysiological study etc. On the other hand, for Cardiologists, ECGs are just the first line of investigations & if they have any suspicions, they have easier access to the next line of investigations.
Secondly, we often have less information & less time when we make decisions based on the ECGs. This is especially true with the sicker patients in Resus, for whom we often must make immediate decisions based on ECGs, even before the labs are back (Eg: Troponins).
Misinterpretation of ECGs results in significant morbidity & mortality. It also makes us liable for lawsuits.
If you are going to work in the ED for the rest of your life (especially in Senior Decision Maker roles), you need to be an expert with ECGs. Even if you see only 20 ECGs per day with an average of 5 shifts per week, you are interpreting over 5200 ECGs per year on average. That is over a 156,000 ECGs over a 30 year career in EM.
There are quite a few studies done on the ECG interpretation skills of doctors, including a meta-analysis of 78 original studies published in JAMA (September 2020) which found that the accuracy of ECG interpretation was relatively low across all grades of Physicians & medical students, with the median accuracy being 55% across all grades. The conclusion was that Physicians at all training levels had deficiencies in ECG interpretation.
An even more recent (September 22nd 2022) but smaller study published by Abdalla A et al which looked at the proficiency of ECG interpretation amongst junior doctors of different grades in one of the largest NHS trusts in the UK have demonstrated overall low levels of competency regardless of grade. The overall score for the ECG quiz in this study was 45%, even though 75.8% of the participants involved had more than 2 years of experience since graduating from medical school.
In essence, as per these studies, the probability of a doctor interpreting an ECG accurately is comparable to a coin flip - there is around 50% chance of getting it right.
When you consider the fact that the ECGs used for testing in these studies are more likely to be classical 'textbook' ECG patterns and with isolated abnormalities (as opposed to multiple ECG abnormalities in the same ECG), it makes you wonder what the real accuracy would be in a daily clinical practice where ECGs often have neither classical 'textbook' patterns nor have isolated abnormalities.
In short, we are probably not as good as we think we are in ECG interpretation.
I believe that there are 3 main reasons for this.
First & foremost, it has to do with how ECGs are taught.
Though ECGs are taught in medical schools, while it provides an introduction to ECG interpretation, it is generally insufficient for day to day clinical practice. There is hardly any significant practice of ECG interpretation during medical schools & as a result, most graduating doctors are not confident about ECG interpretation beyond a few basic rhythms. I believe this is true in many countries - not just in UK or in India (where I trained).
Most of the ECG learning occurs when we start working clinically - usually taught at bedside in bits & pieces over time by senior colleagues (Registrars, Consultants etc). While this is how many have learnt ECGs & it has helped us develop pattern recognition, it has an inherent drawback- that there are gaps in the knowledge of ECG interpretation. Often, ECG teaching sessions are also conducted by departments occasionally which also helps develop pattern recognition.
In addition, ECG interpretation is also learnt by reading books, blogs or watching online ECG teaching, attending workshops etc. All these helps develop pattern recognition. But most of these are done based on the individual's personal interest.
Then what is the problem with this style of learning?
There are 3 main problems with this sort of learning.
Gaps in knowledge required to interpret ECGs accurately.
Complete dependence on Pattern Recognition for interpretation of ECGs.
Lack of a conceptual understanding.
ECGs are difficult to teach.
Because of the complex pathophysiology & wide range of variations involved, it is not easy to teach ECGs. Usually when taught by Cardiologists, they often go into the intricacies which may not be relevant to an ED doctor. When taught by non-cardiologists, the teaching is usually done with focus on building pattern recognition with limited deductive analysis.
In fact, some of the best ECG teachers online use case based approach to ECG to strengthen pattern recognition, but don't teach the basics. A knowledge of basics is assumed, but experience over the past 10 years has taught me that this is not always the case. Many ED clinicians, including senior clinicians are not clear with some of the so called 'basics'. A good knowledge of relevant concepts & deflections lays the foundation for accurate & expert level interpretation of ECGs.
A good example is electrical axis. A significant number of clinicians are not comfortable with axis - they can calculate it, but they don't fully understand it & some even think that it has no significant relevance in ED - which could not be further from the truth. An understanding of electrical axis lies at the core of expert level ECG interpretation & helps understand & interpret many difficult ECGs.
ECGs are difficult to learn independently.
It is generally difficult to learn ECGs by reading books without guidance.
While there are a lot of excellent online ECG resources out there (both free & paid), many of these do not cover the concepts involved. Many of them do not teach the basics as it is assumed to be common knowledge.
Many of the ECG interpretation workshops are 1 day courses & the general practice is to cover all major aspects of ECG interpretation during the session. While this might be adequate for general medical doctors (F1-2 / SHO level) looking to learn the basic common ECG patterns, it is not sufficient for senior level doctors in any acute specialty - be it Emergency Medicine, Acute Medicine, Critical Care etc. Unfortunately, it is a reality that there are few resources exclusively meant for upgrading ECG interpretation skills for senior ED doctors (HSTs, Consultants etc).
There are 2 approaches to ECG interpretation.
Pattern recognition
Deductive analysis
Pattern recognition is the most common method of ECG teaching wherein repeated exposure to the same patterns results in familiarity of the ECG pattern. It is the first step for all ECG interpretation and is mandatory to be able to interpret ECGs.
Pros:
Useful in diagnostic ECGs Eg Hyperkalemia, STEMI etc. Hence very helpful in ECG Quizzes & exams.
It takes less time & effort to learn.
Easier to teach using pattern recognition.
Cons:
Failure to see beyond the patterns you are familiar with.
It cannot be relied upon when you have complex ECGs or multiple pathologies simultaneously.
Depending on Pattern recognition alone to interpret ECGs makes you more prone to errors in ECG interpretation, especially in nondiagnostic ECGs (which is what is mostly seen in clinical practice).
Deductive analysis is the lesser known, but mandatory second step for senior level ECG interpretation. It involves an understanding of the basic concepts & trying to figure out what is happening in the heart based on what you see on the ECG.
Pros:
Helpful in all ECGs including both diagnostic & non diagnostic ECGs.
Even in complex ECGs, it helps pick up findings even if you are unsure of how to interpret it.
Lesser probability of errors.
Increases credibility with Cardiologists & makes life easier at work.
Cons:
Takes more time & effort to learn.
More difficult to teach as it requires a thorough understanding of concepts and well as how to simplify it for the audience.
Very limited resources for learning Deductive analysis for senior EM clinicians. Not a common method of teaching beyond Cardiologists & ECG nerds/experts/enthusiasts.
Using both Pattern Recognition & Deductive Analysis in a balanced manner should
change your ECG interpretation skills sufficiently enough to change your clinical practice.
Ischaemic Heart Disease is singlehandedly the world's biggest killer responsible for 16% of the world's total deaths (WHO data for 2019). And ECGs are the first line investigation in the evaluation of any heart disease. But is there a proportional importance given to ECG teaching in undergraduate & postgraduate training?
ECGs are assumed to be one of those things which is 'learnt on the job', whereas in reality, it is something that needs to be taught as a 'subject' in itself, with specific aims & objectives.
Most of the resources that are available, are directed at junior level clinicians. At the other end of the spectrum, the resources directed at senior clinicians often assume familiarity with complex ECG concepts and therefore do not discuss them. As a result, the complex discussions often ends up being useful to only Cardiologists & other ECG enthusiasts, thereby limiting its usage.
We spend days learning complex skill sets like ATLS, ALS, PALS etc & then reaccredit it every couple of years for the rest of our working lives. And these are skills for which we always have additional help in the form of trauma teams, cardiac arrest teams etc.
But when it comes to the incredibly complex skill of ECG interpretation, there is no specific curriculum which enables senior level ECG interpretation in ED. Nor is there any additional support for ECG interpretation apart from seeking Cardiology opinion (which can't be utilised for all ECGs we see in a shift).
Due to a variety of reasons (including a lack of access to appropriate resources), a significant number of ED doctors don't actively upgrade ECG skills beyond what they learn in the initial part of their career, apart from the occasional ECG blog or online teaching.
Often the complex and dangerous ECGs appear very subtle & normal like and is therefore easily missed by relatively inexperienced ECG interpreters (and sometimes even by senior clinicians). While it is true that any doctor should be able to sign off ECGs, it makes more sense from a patient safety point of view to have experienced ECG interpreters to sign off ECGs in EDs. Or at least review all ECGs prior to discharge from ED.
My 2 cents on ECG interpretation, especially for senior level ED doctors
If you are going to be working in an Emergency Department for the rest of your life, you need to be great with ECGs.
Considering that we make a lot of clinical decisions based on ECGs, it is imperative that we are experts in it.
" Trying to interpret ECGs using only pattern recognition is like
trying to untie a knot with one arm tied behind your back. "