Despite the critical role diagnostic ECG plays in patient management across specialties, there are persistent shortcomings in ECG training that have been described and discussed at length in medical literature over decades.
The problem starts in medical school, which may leave graduates ill-prepared for ECG interpretation as they progress through their training, ultimately resulting in suboptimal accuracy—even when experienced physicians are reading ECGs.
The Pervasive Issue of Missed Diagnoses
In a Journal of Hospital Medicine paper proposing ECG interpretation competencies for undergraduate and postgraduate trainees, experts from the International Society of Electrocardiology and the International Society of Holter and Noninvasive Electrocardiology (ISE/ISHNE) cite data showing that senior medical students miss anywhere from 26% to 62% of acute MIs.
Another study in the Journal of Electrocardiology found that first-year internal medicine residents gave the correct interpretation of common ECGs only half of the time, with 10% missing acute MIs, 40% missing ventricular tachycardia, and 87% missing complete heart block. Almost all of the participants deemed their prior ECG training insufficient. Even later in training, cardiology subspecialty fellows failed to catch up to 26% of STEMIs on ECGs that had multiple findings, according to a study in the Canadian Journal of Cardiology.
A recent meta-analysis in JAMA Internal Medicine showed that, across training levels, median accuracy for ECG interpretation was just 54% on pretraining assessments and 67% on post-training assessments. Performance on pretraining assessments was lowest among medical students (42.0%), increasing to 55.8% for residents, 68.5% for practicing physicians as a whole, and 74.9% for cardiologists.
"Improvement in both training in and assessment of ECG interpretation appears warranted, across the practice continuum," the investigators concluded. "Standardized competencies, educational resources, and mastery benchmarks could address all these concerns."
Causes and Consequences of Inadequate ECG Training
Researchers writing in BMJ Open proposed several explanations for the deficit, noting first the difficulty inherent to teaching and learning how to interpret ECGs. In addition, although exposure during clinical encounters is a key way of acquiring the skill of ECG interpretation, "experiential learning alone does not guarantee ECG competence unless it is supplemented by structured teaching," they write. And finally, "medical knowledge is ever-expanding, and there is limited time allocated to the teaching of electrocardiography in medical curricula."
Indeed, experts in the Journal of Electrocardiology note that programs have to bring trainees up to speed on a variety of diagnostic technologies, including CT, MRI, and ultrasound, which limits the amount of time that can be dedicated to ECG interpretation.
This can have real and potentially life-threatening consequences. Researchers writing in the GMS Journal for Medical Education point out that when mistakes are made in ECG interpretation, it can spur inappropriate downstream testing and delay diagnosis and treatment.
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Possible Training Methods
As with any skill, attaining proficiency in ECG interpretation requires deliberate practice. However, "structured repeated practice and feedback for ECGs is likely not provided to most medical students," according to researchers in the GMS Journal for Medical Education study.
They explored the learning curve for ECG rhythm strip interpretation among medical students when a more structured program of deliberate practice involving online instruction was used. Feedback was provided for each case. The investigators determined that students would need to complete an average of 112 minutes of training and 34 practice cases to get a 75% grade on an ECG rhythm strip exam. The approach was associated with high student satisfaction.
The authors acknowledge, however, that interpretation of 12-lead ECG is more complex and might require more practice time. That thought is reflected in guidance from various professional groups: in a 2001 clinical competency statement published in Circulation, for instance, the American College of Cardiology and the American Heart Association (ACC/AHA) recommend a minimum of 500 supervised interpretations to learn how to interpret 12-lead ECGs, as well as 100 interpretations each year to maintain proficiency.
In 2015 a Core Cardiovascular Training Statement (COCATS) task force published a different recommendation in the Journal of the American College of Cardiology, saying that interpreting roughly 3,000 to 3,500 ECGs over a three-year period "should provide ample experience to acquire such competencies" for trainees.
That volume of ECGs would require a lot of feedback, presenting a logistical challenge to getting medical students and trainees up to speed on ECG interpretation. In the GMS Journal for Medical Education study, feedback was automated and provided by computer algorithms, which took much of the burden off the instructors. That approach also enhanced the consistency and quality of feedback over time as the program uncovered trainees' common errors.
The BMJ Open paper showed that computer-assisted training in ECG interpretation was no better for attaining ECG competence than face-to-face instruction, based on research from multiple studies. However, when computer-assisted approaches were used in a "blended learning context," they came out on top, "especially if trainees had unlimited access to teaching materials and/or deliberate practice with feedback."
Establishing Competency Standards
Various groups have proposed that competency standards for ECG training should be applied in medical school and in subsequent years of instruction. In the ISE/ISHNE competency paper published in 2018, the authors noted that "currently, many medical education programs lack an organized curriculum and competency assessment to ensure trainees master this essential skill."
They proposed classifying the ECG patterns that need to be mastered into four groups based on clinical importance:
- Group A: Common patterns that represent electrocardiographic emergencies that require prompt intervention, such as STEMI or ventricular tachycardia.
- Group B: Common nonemergency patterns that don't necessarily require immediate treatment, such as patterns indicative of LVH or bradycardia syndromes.
- Group C: Uncommon electrocardiographic emergencies, such as ventricular preexcitation or acute drug effects.
- Group D: Uncommon nonemergency patterns, such as right atrial abnormalities or left posterior fascicular block.
The authors recommend that medical students attain proficiency in identifying patterns in groups A and B, whereas residents should also be able to identify patterns in groups C and D by the end of postgraduate year 1. Importantly, the authors assert that, regardless of how ECG interpretation is taught, programs "should ensure that no electrocardiographic emergency (class A condition) is ever missed by a trainee."
