The 12-lead electrocardiogram (ECG) remains one of the most widely used and readily available diagnostic tests in modern medicine.1 Reflecting the electrical behavior of the heart, this point-of-care diagnostic test is used in almost every area of medicine for diagnosis, prognostication, and selection of appropriate treatment. The ECG is sometimes the only and most efficient way of detecting life-threatening conditions, thus allowing a timely delivery of emergency care.2 However, the practical power of the 12-lead ECG relies on the ability of the clinician to interpret this test correctly.
For decades, ECG interpretation has been a core component of undergraduate and postgraduate medical training.3-5 Unfortunately, numerous studies have demonstrated alarming rates of inaccuracy and variability in interpreting ECGs among trainees at all levels of education.4,6,7 Senior medical students have been repeatedly shown to miss 26% to 62% of acute myocardial infarctions (MI).6,8-10 Another recent study involving internal medicine residents demonstrated that only half of the straightforward common ECGs were interpreted correctly, while 26% of trainees missed an acute MI and 56% missed ventricular tachycardia (VT).11 Even cardiology subspecialty fellows demonstrated poor performance, missing up to 26% of ST-elevation MIs on ECGs that had multiple findings.12 Inaccurate interpretations of ECGs can lead to inappropriate management decisions, adverse patient outcomes, unnecessary additional testing, and even preventable deaths.4,13-15
Several guidelines have emphasized the importance of teaching trainees 12-lead ECG interpretation and have recognized the value of assessments in ensuring that learners acquire the necessary competencies.16-19 Similarly, there have been many calls for more rigorous and structured curricula for ECG interpretation throughout undergraduate and postgraduate medical education.11,16 However, we still lack a thoughtful guideline outlining the specific competencies that medical trainees should attain. This includes medical students, nurses working in hospital and in out-of-hospital settings, and residents of different specialties, including emergency medicine, cardiology, and electrophysiology (EP) fellows.
Setting goals and objectives for target learners is recognized to be the initial step and a core prerequisite for effective curriculum development.20 In this publication, we summarize the objectives from previously published trainee assessments and propose reasonably attainable ECG interpretation competencies for both graduating medical students and residents at the end of their postgraduate training. This document is being endorsed by researchers and educators of 2 international societies dedicated to the study of electrical heart diseases: the International Society of Electrocardiology (ISE) and the International Society of Holter and Noninvasive Electrocardiology (ISHNE).
Current Competencies in Literature
We performed a systematic search to identify ECG competencies that are currently mentioned in the literature. Information was retrieved from MEDLINE (1946-2016) and EMBASE (1947-2016) by using the following MeSH terms: electrocardiogram, electrocardiography, electrocardiogram interpretation, electrocardiogram competency, medical school, medical student, undergraduate medicine, undergraduate medical education, residency education, internship, and residency. Our search was limited to English-language articles that studied physician trainees. The references of the full-length articles were examined for additional citations. The search revealed a total of 65 publications involving medical students and 120 publications involving residents. Abstracts of publications were then assessed for relevance, and the methods of the remaining articles were scrutinized for references to specific ECG interpretation objectives. This strategy narrowed the search to 9 and 14 articles involving medical students and residents, respectively. Studies were not graded for quality because the purpose of the search was to identify the specific ECG competencies that authors expected trainees to obtain. Almost all the articles proposed teaching tools and specific objectives that were defined by the investigators arbitrarily and assessed the trainee’s ability to interpret ECGs (summarized in supplementary Table).
Defining ECG Interpretation Competencies
The initial draft of proposed ECG interpretation competencies was developed at Queen’s University in Ontario, Canada. A list of ECG patterns and diagnoses previously mentioned in literature was used as a starting point. From there, each item was refined and organized into 4 main categories (see Figures 1 and 2).
Class A “Common electrocardiographic emergencies” represent patterns that are frequently seen in hospitals, in which accurate interpretation of the ECG within minutes is essential for delivering care that is potentially lifesaving to the patient (eg, ST-elevation MI).
Class B “Common nonemergency patterns” represent ECG findings that are encountered daily in patients who are not acutely ill, which may impact their care in the appropriate clinical context (eg, left ventricular hypertrophy).
Class C “Uncommon electrocardiographic emergencies” represent ECG findings that are not encountered on a daily basis but can be potentially lifesaving if recognized (eg ventricular preexcitation).
Class D “Uncommon nonemergency patterns” represent findings that are uncommon but may diagnostically contribute to patient care in a clinically appropriate setting (eg, right atrial abnormality).
ECG interpretation patterns were then assigned to medical students and residents based on the specific goals of training. At the time of graduation, medical students should develop the foundation for learning ECG interpretation in residency training, provide ECG interpretation and initial management for electrocardiographic emergencies, and obtain assistance from a more senior medical professional within a clinically appropriate time frame. The training goal for a resident is to develop ECG interpretation competencies for safe independent clinical practice (Figure 1).
The final segregated ECG interpretation competencies were distributed to members of ISE and ISHNE for input, modifications, and revisions. The proposed list of competencies went through several revisions until a consensus was reached.
The final distribution of ECG patterns is illustrated in Figure 2. (Figure 3 defines the learning objectives for each ECG pattern defined in Figure 2.) Here, we provide a rationale for
Class A: Common Electrocardiographic Emergencies
This group contains ECG findings that require recognition within minutes to deliver potentially lifesaving care. For this reason, undergraduate medical education programs should prioritize mastering class A conditions to minimize the risk of misdiagnosis and late recognition.
Class A patterns include ST elevation MI (STEMI) and localization of territory to ensure ST-segment elevations are seen in contiguous leads.29,30 Students should learn the criteria for STEMI as per the “Universal Definition of Myocardial Infarction” and be aware of early signs of STEMI that may be seen prior to ST-segment changes, such as hyper-acute T-waves (increased amplitude and symmetrical).30
Asystole, wide complex tachycardias, and ventricular fibrillation (VF) are all crucial ECG patterns that must be identified to deliver advanced cardiac life support (ACLS) care as per the 2010 AHA Guidelines for cardiopulmonary resuscitation and emergency cardio care.31 Of note, students should understand the differential diagnosis of wide complex tachycardias and should be able to suspect VF in clinically appropriate scenarios. We included the category “unstable/symptomatic supraventricular tachycardia” to represent rapid rhythms that are supraventricular in origin, which either produce symptoms or cause impairment of vital organ function.31 In emergency situations, it may not be crucial to correctly identify the specific supraventricular rhythm to deliver ACLS care; hence, the specific supraventricular tachycardia diagnoses were included in Class B.
Finally, we believe that medical students should be able to recognize long QT, hypo/hyperkalemia, and distinguish types of atrioventricular (AV) block. Distinguishing types of AV block is important because both third degree AV block and second degree AV block Mobitz II can be life threatening and require further investigation or emergency treatment in an inpatient setting.32 Prompt recognition of long QT is crucial because it can be associated with ventricular tachyarrhythmias. This includes a polymorphic pattern characterized by the twisting of QRS peaks around the baseline (torsades des pointes), which can eventually lead to VF.
Class B: Common Nonemergency Patterns
Class B patterns represent common findings that are seen on a daily basis that may impact patient care in a clinically appropriate context. Diagnoses in this section were divided into “tachycardia syndromes,” “bradycardia syndromes,” “conduction abnormalities,” “ischemia,” and “other.”
Undergraduate trainees should become proficient in identifying the cause of bradycardia and distinguishing types of AV blocks. Similarly, they should also have an approach to differentiate tachycardia syndromes.33,34 These skills are required to correctly manage patients in both inpatient and outpatient settings. They should be taught in undergraduate programs and reinforced in postgraduate training.
Common findings, such as bundle branch blocks, left anterior fascicular block, premature ventricular/atrial complexes, electronic pacemakers, and left ventricular hypertrophy, are essential to the daily interpretation of ECGs. Junior learners should be proficient in recognizing these patterns. Findings consistent with pericarditis are not uncommon and can be very helpful to guide the clinician to the diagnosis. Notable exceptions from the medical student competency list include detection of lead misplacement, common artifacts, nonspecific intraventricular conduction delay, interatrial block, and benign early repolarization. These findings require a deeper understanding of electrocardiography and would be more appropriate for senior learners.
Class C: Uncommon Electrocardiographic Emergencies
Class C findings represent uncommon conditions that, if recognized, can prevent serious adverse patient outcomes. These include preexcitation, STEMI with preexisting left bundle branch block sinus pauses, Brugada pattern, hypothermia, effects of toxic drugs, ventricular aneurysm, and right ventricular hypertrophy. The recognition of these patterns is crucial to avoid severe adverse patient outcomes, and independent practicing physicians should be aware of these findings. However, given that a high proportion of senior medical students miss common electrocardiographic emergencies, undergraduate medical education programs should instead focus resources on ensuring medical students are proficient in identifying class A and class B conditions.6,8-10 Postgraduate programs should ensure that postgraduate trainees can identify these potentially life-threatening conditions (see section “How to Teach Electrocardiology”).
Class D: Uncommon and Nonemergency Patterns
Class D findings represent less common findings that are not seen every day and do not require urgent medical attention. These include right atrial abnormality, left posterior fascicular block, low atrial rhythms, and electrolyte abnormalities that exclude potassium. Notably, electrolyte abnormalities are important to identify; however, typically, treatment is guided by the lab results.35 Overall, postgraduate trainees should certainly be aware of these findings, but medical student training should instead focus on learning the framework and correctly identifying class A and class B ECG patterns.
HOW TO TEACH ELECTROCARDIOLOGY
Teaching ECG Interpretation Strategies
No clear teaching approaches to ECG interpretation have been described in the literature, and no recommendations on knowledge translation have been formally explored. A possible educational approach to the teaching of electrocardiology could involve several methods for helping students with ECG interpretation:36
1. Pattern recognition: The ECG, at its most immediate level, is a graphic image, and recognition of images is essentially recognition of patterns. These patterns can only be learned through repeated visualization of examples with a written or verbal explanation. Repeated visualization over time will help avoid “erosion” of knowledge. Examples of learning tools include periodic in-person ECG rounds, well-illustrated books or atlases, and online tools with good quality ECGs and explanations. These learning opportunities are strongly reinforced by collecting cases from the clinical encounters of the trainee that illustrate the aforementioned patterns. Some of these patterns can be found in guidelines, such as the one published by the AHA and ACC.29
2. Application of published criteria: Guidelines, review papers, and books offer diagnostic criteria for many entities, such as chamber enlargement, bundle branch blocks, and abnormal Q waves. Learning these criteria and applying them to the analysis of ECGs is a commonly used learning strategy.
3. Inductive-deductive reasoning: This strategy requires a deeper understanding of the pathophysiology behind ECG patterns. It requires ECGs to be interpreted in a certain clinical context, and the goal of ECG interpretation is to answer a clinical question that is used to guide patient care. This strategy typically employs the use of algorithms to lead the interpreter to the correct diagnosis, and mastery of this skill grows from ongoing clinical experience. Examples of the “inductive-deductive reasoning” are localizing an accessory AV pathway, the differential diagnosis of narrow or wide complex tachycardias, and identifying the site of coronary artery occlusion in a patient with a STEMI.
4. Ladder diagrams: Ladder diagrams have been used for over 100 years to graphically illustrate the mechanism of arrhythmias. They can be incredibly useful to help learners visualize impulse conduction in reentry mechanisms as well as other abnormal rhythms. However, there are some rhythms that are difficult to illustrate on ladder diagrams.37
5. Peer and near-peer teaching: Peer teaching occurs when learners prepare and deliver teaching material to learners of a similar training level. The expectation to deliver a teaching session encourages students to learn and organize information in thoughtful ways. It builds strong teamwork skills and has been shown to positively affect all involved learners.38-40
Each ECG interpretation strategy has its advantages, and we recommend that students be exposed to all available approaches if teaching resources are available.
Teaching Delivery Format
Each of the above teaching strategies can be delivered to students in various ways. The following teaching formats have been previously documented in the literature:
1. Classroom-based teaching: This is a traditional learning format that takes place in a large- or small-group classroom. Typically, these sessions are led by a single instructor, and they are focused on the direct sharing of information and group discussion.41
2. Electronic practice tools: Numerous electronic tools have been developed with the purpose of providing deliberate practice to master ECG interpretation. Some of these tools employ active learner engagement, while others provide a bank of ECGs for self-directed passive learning.42-46
3. Video lectures: Short video lectures have been created to facilitate self-directed lecture based learning. These lectures are hosted on a variety of web-based platforms, including YouTube and Vimeo.47
4. Traditional and electronic books: Numerous traditional textbooks have been published on ECG interpretation and are designed to facilitate independent learning. Some textbooks directly deliver teaching material, while others contain sets of ECGs to allow for repetitive practice. More recently, iBooks incorporating self-assessment tools have been used to assist ECG teaching.34 The advantage of these tools is that they can also be used to supplement in-person classes.
5. Games: A unique ECG interpretation learning strategy consists of using puzzles and games to learn ECGs. This is meant to improve student engagement and interest in learning ECG interpretation.48
Given that there is currently a lack of evidence-based data to support 1 instructional format over another, we do not favor any particular one. This decision should be left to instructors and individual learners based on their preference and available resources. Further studies would be helpful to determine the effectiveness of various methods in teaching ECG interpretation and to identify any additional specific factors that facilitate learning.
1. Longitudinal ongoing feedback: This form of feedback universally takes place in all training programs and focuses on direct observation and point-of-care feedback by a senior healthcare professional during clinical practice. Typically, the feedback is informal and is centered around specific case presentations.
2. Formative testing: This assessment strategy is aimed at monitoring the learning of trainees and providing them with appropriate feedback. Tutors and teachers can use this data to individualize instruction and fill any training gaps that individuals and the class may have. Students themselves can use this information to encourage additional study to ensure they acquire required skills. Examples of formative testing are low-stakes in-training exams and asking audience questions during a workshop or lecture.49
3. Summative testing: Summative assessments are created to measure the level of proficiency developed by a learner and compare it against some standard or benchmark. This form of assessment establishes the extent to which educational objectives have been met. The most common example is an end-of-term examination.
Online ECG examination has been successfully used to provide methods of testing. They are easy to distribute, highly convenient for learners, and allow the display of high-quality graphics. They can also be graded electronically, thereby minimizing the resources required to administer and grade exams.36,50
We recommend using a combination of assessment formats to ensure the optimal evaluation of learner skill and to focus learning on areas of weakness. Summative assessments are highly valuable to ensure learners acquired the necessary ECG interpretation competencies. Remediation strategies should be available to provide additional practice to learners who do not meet competencies expected at their level of training.
The Need for ECG Interpretation Competencies and Milestones
Since the introduction of ECG in the late 1800s, there continues to be a significant variation in ECG interpretation skills among trainees and medical professionals.4,6-12 Concerns continue to exist about the rate of missed diagnoses involving critical ECGs, leading to inappropriate patient management decisions. Despite the obvious need, teaching ECG interpretation is given little emphasis in medical education, and the curriculum remains quite disorganized. In this position paper, we call for a more structured ECG interpretation curriculum in medical education and hope to assist this process by assigning ECG patterns to 2 milestones in training: graduating medical students and first year postgraduate medical residents.
Defining competencies would help medical education programs to focus resources on teaching clinically important conditions for the appropriate level of training. We divide ECG findings into 4 categories (classes A to D), and we place emphasis on learning electrocardiographic emergencies early in training and spending less time on ECG findings that are unlikely to change patient management.
The goal is to ensure 100% recognition of class A (electrocardiographic emergencies) by the end of medical school. To ensure each medical education program fulfils this goal, a structured curriculum including a summative assessment is required.
Methods of Teaching
Various instructional mediums have been successfully implemented to teach ECG interpretation competencies, including lectures, puzzles, web-based programs, iBooks, and YouTube.34-41-44,47,48.51-53 A survey of clerkship directors in internal medicine revealed that 75% of clerkship programs teach ECG interpretation in a classroom lecture-based setting, 44% use teaching rounds, and only 17% utilize online/web-based instruction.3 Canadian family medicine programs have a relatively equal distribution between classroom-based, computer-based, and bedside teaching.5
In comparing the efficacy of instructional styles, several small comparative studies favor an electronic teaching format because of the enhanced learner interaction and visual learning, but there does not appear to be a consistently proven large advantage of 1 teaching format over another.43,48,51,54 The overall theme emerging from this literature is the importance of repetition and active engagement in ECG interpretation, which appear to be more important than 1 particular strategy.22 Computer-based training appears to deliver these 2 qualities, unlike the traditional lecture-style passive learning model. The concept of repetition and engagement is also well supported in medical education literature outside ECG interpretation.55,56
Given these data, we recommend that each medical education program select teaching methods based on their available resources, as long as adequate teaching time is allotted to ensure that trainees acquire the competencies defined in this publication.
It appears that the larger factor in determining ECG interpretation performance is not the learning format, but the form of assessment. Two studies have demonstrated that summative assessment substantially improves ECG interpretation performance when compared with formative assessment; in fact, this effect was so large that it overshadowed any small difference in teaching formats.57,58 This concept aligns with medical education literature, which acknowledges that assessment drives learning by raising the stakes, thereby boosting student effort and encouraging learning to an effect much larger than can be generated by any particular learning style.57,59 Nevertheless, well-designed formative assessment can focus students on effective learning by identifying gaps and important information.60 Only 33% of Canadian family medicine residency programs and 71% of American clerkship programs have formal assessment of ECG interpretation skills.3,5 There is no doubt that assessment, both formative and summative, should be implemented in all undergraduate and postgraduate medical training programs. Online assessment methods have the advantage of delivering high-quality images and a variety of question formats; hence, their use should be encouraged.36,50,61-63
Teaching Personnel and Timing of Training
Who should teach ECG interpretation and when should this teaching take place? ECG interpretation in training programs is typically taught by attending physicians in each respective field. However, given that there is a large ECG interpretation error rate by noncardiologist physicians, we advise that ECG training content be created with input from own-specialty attending physicians and cardiologists.4 This teaching should take place early in medical school at the time medical students learn pathophysiology of the heart and should continue throughout training. Longitudinal training is preferred to block-based training because of improved resident satisfaction, but medical education literature did not reveal a difference in student performance with either strategy.64-66
Despite its immense clinical value, there continues to be a lack of a comprehensive ECG interpretation curriculum in medical education programs. The goal of this position paper is to encourage the development of organized curricula in undergraduate and postgraduate medical education programs, and to ensure the acquisition of level-appropriate ECG interpretation skills while maintaining patient safety. We assist this process by grouping ECG findings into 4 classes (A to D) based on the frequency of encounter and emergent nature and by assigning them to each level of training. Methods of teaching ECG interpretation are less important and can be selected based on the available resources of each education program and student preference; however, online learning is encouraged. We also recommend that summative trainee evaluation methods be implemented in all programs to ensure that appropriate competencies are acquired and to further encourage self-directed learning. Resources should be allocated to ensure that every trainee is reaching their training milestones and should ensure that no electrocardiographic emergency (class A condition) is ever missed by a trainee. We hope that these guidelines will inform medical education systems and help prevent adverse patient outcomes caused by the misinterpretation of this valuable clinical diagnostic tool.
On behalf of all authors, the corresponding author states that there is no conflict of interest. This manuscript did not utilize any sources of funding.