Interpretation of electrocardiograms by first-year residents: the need for change

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1 Available online at Journal of Electrocardiology 42 (2009) Interpretation of electrocardiograms by first-year residents: the need for change Dayana Eslava, MD, Sandeep Dhillon, MD, Jeffrey Berger, MD, Peter Homel, Steven Bergmann, MD, PhD Division of Cardiology, Department of Internal Medicine, University Hospital and Manhattan Campus for the Albert Einstein College of Medicine, Beth Israel Medical Center, New York, NY, USA Received 10 January 2009 Abstract Keywords: Background: Prior studies have shown that misinterpretation of the electrocardiogram (ECG) can lead to inappropriate diagnoses and clinical decisions. This may be particularly true during the first month of postgraduate training. This study was designed to assess proficiency in ECG interpretation among residents at the start of their internal medicine (IM) residency. Methods: Ten ECGs were selected from IM department teaching files. All were representative of conditions that a starting IM resident should be able to identify. The ECGs had 1 correct primary diagnosis and a short list of secondary findings as determined by 2 cardiologists who reviewed them independently. Fifty-two first-year IM residents were given copies and asked to record their interpretations and an assessment of their certainty in each interpretation. Certainty was scored on a scale of 0 to 4 (0 representing a guess and 4 representing 100% certainty). Two blinded, independent graders scored each interpretation on a scale of 0 to 2 (0 = incorrect, 1 = partially correct, 2 = correct). Results: Overall, only half of all ECGs were read correctly. For the most critical diagnoses, the mean scores were as follows: 1.73/2.0 for acute myocardial infarction, 1.5/2.0 for atrial flutter, 1.11/2.0 for ventricular tachycardia, and 0.23/2.0 for complete heart block. The average level of certainty recorded by all participants was low at 18.5 of a maximum of 40. Conclusions: Internal medicine residents at the beginning of their residency training demonstrated low overall proficiency in interpreting ECGs and self-perceived confidence. Nearly all residents felt that their training was insufficient. These findings emphasize the need for improved and more effective training in ECG interpretation for physicians starting residency Elsevier Inc. All rights reserved. Electrocardiogram interpretation; Internal medicine; Residency training; Proficiency; Certainty Introduction Electrocardiography, introduced in 1902 by Einthoven, is the most commonly used procedure for the diagnosis of heart disease. It is a frequently performed procedure by internists and family practitioners 1 as well as by emergency department physicians and cardiologists. This procedure is simple, safe, reproducible, and relatively economical. As a record of electrical activity of the heart, it is a technology that provides information not readily obtained by other methods. 2 The 12-lead electrocardiogram (ECG) has numerous potential clinical uses. It serves as the criterion standard for Corresponding author. Division of Cardiology, Department of Internal Medicine, University Hospital and Manhattan Campus for the Albert Einstein College of Medicine, Beth Israel Medical Center, First Avenue at 16th Street, New York, NY 10003, USA. address: dayanaeslava@hotmail.com noninvasive diagnosis of arrhythmias and conduction disturbances, and it occasionally is the only marker for the presence of heart disease. 3,4 It is imperative that physicians in any specialty whose interpretation of ECGs contributes to clinical decision making have sufficient knowledge to make accurate diagnosis. Patients trust the physician to accurately interpret their ECG. However, many physicians are unaware of their limitations and believe that they can interpret ECGs well. 1 Adequate knowledge should include the ability to define, recognize, and understand the basic pathophysiology of certain electrocardiographic abnormalities. 4 Very little is known about ECG interpretative skills of medical residents. 5 Accordingly, this study was designed to test the accuracy of interpretation of a variety of basic ECGs among first-year internal medicine (IM) residents. A secondary goal was to identify the particular weaknesses in /$ see front matter 2009 Elsevier Inc. All rights reserved. doi: /j.jelectrocard

2 694 D. Eslava et al. / Journal of Electrocardiology 42 (2009) ECG interpretation that can be targeted during medical training to improve patient care. Materials and methods Study design This study is a questionnaire-based assessment of first-year IM residents and their interpretation of ECGs. Ten 12-lead ECGs were selected from teaching files of the IM training program. The chosen ECGs were straightforward and easily diagnosed examples. All ECGs were reviewed independently by 2 cardiologists who were asked to give a diagnosis for each ECG. The cardiologists were blinded to any clinical information or previous ECGs. The 2 cardiologists were in agreement about the correct diagnosis of each ECG. It was determined that each ECG had only 1 possibly correct primary diagnosis and a short list of secondary findings. There was 100% agreement on the diagnoses by the 2 experts. The 10 ECGs represented examples of conditions that an IM resident would be expected to diagnose during the first postgraduate year (PGY-1) of training. Included were an ECG of sinus bradycardia and examples of acute myocardial infarction (AMI), atrial flutter, ventricular tachycardia (VT), supraventricular tachycardia (SVT), acute pericarditis, left ventricular hypertrophy (LVH), Wolff-Parkinson-White, second-degree anteroposterior (A-V) block, and complete heart block. All of the 12-lead ECGs but the AMI example had an accompanying rhythm strip. Three of the ECGs chosen were examples of emergencies that require immediate and accurate interpretation (AMI, VT, and complete heart block). Table 1 lists the diagnosis of the 10 ECGs used in the study and are listed in the order they appeared in the questionnaire. Fifty-two PGY-1 residents, during their second week of IM training, participated in this study. The participants were handed a stack of ECGs and asked to complete the questionnaire without any prior knowledge of the study. The questionnaire had a fill-in-the-blank format, and the participants were asked to describe their answer on a blank line on a separate answer sheet. None of the ECGs offered multiple choice answers. The PGY-1 residents were asked to interpret each ECG, write the diagnosis, and indicate their degree of certainty for each answer. It was explained that not all ECGs were necessarily abnormal. No clinical history was provided to avoid influencing the participant's interpretation of the ECG. Previous research has demonstrated a strong and Table 1 Primary diagnoses for each ECG No. Diagnosis 1. AMI 2. Sinus bradycardia 3. VT 4. LVH with repolarization abnormality 5. SVT 6. Atrial flutter 7. Wolf-Parkinson-White 8. Complete (3rd-degree) A-V block 9. Acute pericarditis 10. 2nd-degree A-V block type I consistent effect of clinical scenario on the accuracy of ECG interpretation and identification of ECG features for physicians at all levels of training, but especially providers with less experience. 6,7 There was no time limit. The participants were not permitted to consult outside sources while completing the questionnaire. Each ECG was graded on a scale from 0 to 2 (0 = incorrect, 1 = partially correct, 2 = correct); thus, the maximum total score achievable for 10 correctly answered ECGs was 20. If the primary diagnosis was given, the ECG was scored as correct and was granted 2 points. If the primary diagnosis was alluded to or the primary diagnosis was incorrect but the subject mentioned a correct secondary finding, the ECG was scored as partially correct and was granted 1 point. Finally, if the participant was unable to give either the primary diagnosis or any secondary findings, the ECG was scored incorrect and given a zero. The level of certainty was assessed based on a 5- point Likert scale that ranged from 0 to 4 (0 = 0%, 1 = 25%, 2 = 50%, 3 = 75%, 4 = 100%), where 0 represented a complete guess and 4 represented absolute certainty. These certainties were then summed to produce an overall certainty score, which could range from 0 to 40 (for 10 ECGs). The higher the score, the more certain the PGY-1 resident was of the answer. All questions left unanswered were scored a zero. The participants also completed a short questionnaire and stated their sex, their interest in cardiology as a career, and whether they were a categorical or a preliminary PGY-1 resident (first year of IM residency before entering a specialty training). The questionnaire also asked whether the participant felt he had received adequate ECG training during medical school. In addition, the questionnaire evaluated the participant's overall perceived proficiency when interpreting an ECG. Proficiency was evaluated using a scale from 1 through 10 (1 being very low proficiency and 10 very high level of proficiency). The study was approved by the Institutional Review Board of Beth Israel Medical Center. Written informed consent was waived. Statistical analysis Two blinded, independent graders (J.B. and L.E.) scored each participant's answer on a scale from 0 to 2 (0 = incorrect, 1 = partially correct, 2 = correct). A third party (D.E.) reconciled any disagreement between the graders. The analyses included both an investigation of PGY-1 resident's interpretation of each individual ECG and the combination of the results of the 10 ECGs for an overall maximum achievable score of 20. Parametric statistics were used wherever P values were required. A P value less than.05 was taken to mean a statistically significant result. T tests were used to study gender differences between scores and to investigate differences between preliminary and categorical PGY-1 residents. The t test was also used to evaluate for gender differences in ECG interpretation and level of certainty regarding the answers given. A Pearson correlation was used to investigate if there were any correlations between the total score achieved and being interested in a career in cardiology.

3 D. Eslava et al. / Journal of Electrocardiology 42 (2009) Results The study sample consisted of 52 PGY-1 residents at a large university hospital in New York City. The participants were within their first 2 weeks of starting their IM training. There were 28 (54%) men and 24 (46%) women. The overall mean (SD) score achieved in this study was 9.7 (3.9) of a maximum possible score of 20 (range, 2-18; Fig. 1). Men scored a mean (SD) of 10.0 (3.2) versus women who scored 9.5 (4.6; P =.96). The highest total score achieved was 18 of 20 and was achieved by 2 participants. These 2 residents reported their overall level of proficiency as being 4 and 5 of a maximum possible score of 10. The lowest score achieved was 2 of 20 and was attained by 2 participants who reported their overall level of proficiency as being 2 and 1 of 10. Of the 52 PGY-1 residents, 38 (73%) were categorical and 14 (27%) were preliminary. There were no significant differences in the scores achieved by preliminary PGY-1 and categorical PGY-1 (9.6 ± 3.4 vs 9.7 ± 4.1, respectively). Table 2 lists the scores obtained for each individual ECG. When analyzing the ECGs with the most critical diagnoses, results were not better. For each diagnoses, the maximum possible score is 2. The mean (SD) score for the ECG of AMI was 1.73 (0.63) out of 2. The most commonly reported incorrect response was pericarditis, which comprised 80% of the incorrect responses. The mean (SD) score for the diagnosis of VT was 1.11 (0.96) out of 2, with the most common incorrect responses being left bundle branch block (57%), LVH (14%), sinus tachycardia (14%), SVT (9.5%), and no answer (9.5%). The third most critical diagnosis was complete heart block, with participants achieving a mean (SD) score of 0.23 (0.61) out of 2. For this diagnosis, the most common incorrect answer was either bradycardia (31%) or seconddegree heart block, which comprised 17% of the responses. The ECG representing AMI was the most correctly interpreted (83%), whereas the complete heart block ECG was the least correctly interpreted (10%) by participants. The VT ECG was interpreted correctly by 52% of the participants. The degree of certainty about answers was also low. On no ECG were more than 14% of the participants certain about their answer. The mean levels of certainty reported for men and women were 19.5 and 17 of 40, respectively (P =.17). Table 2 ECG interpretation scores No. Diagnosis Correct, Partially correct, Incorrect, 1. AMI 43 (84) 4 (8) 5 (10) 2. Sinus bradycardia 23 (44) 8 (15) 21 (40) 3. VT 27 (52) 4 (8) 21 (40) 4. LVH 15 (29) 12 (23) 25 (48) 5. SVT 22 (42) 9 (17) 21 (40) 6. Atrial flutter 39 (75) 0 (0) 13 (25) 7. Wolf-Parkinson-White 25 (48) 0 (0) 27 (52) 8. Complete (3rd-degree) 5 (10) 2 (4) 45 (87) A-V block 9. Acute pericarditis 10 (19) 2 (4) 40 (77) 10. 2nd-degree A-V block type 13 (25) 17 (33) 22 (42) Total 222 (43) 58 (11) 240 (46) The highest level of certainty was found when interpreting ECGs representing AMI (55%) and atrial flutter (60%). The highest level of uncertainty or guessing was noted for ECGs representing Wolff-Parkinson-White (27%), complete heart block (23%), and acute pericarditis (23%). There was no correlation between the total level of certainty and the total score achieved (r =0.27,P =.054).Table 3 shows the degree of certainty for each answer. Participants were then asked to grade their overall level of perceived proficiency when interpreting ECGs. The mean (SD) self-reported proficiency for the cohort was 4.2 (1.6) out of 10. No PGY-1 resident reported having a general proficiency level, in interpreting ECGs, to be excellent. Forty-three (83%) of the participants thought their overall proficiency level was 5 or less. One participant did not answer this question. There was no correlation between self-perceived proficiency and the total score achieved (r =0.2,P =.16). However, there was a significant correlation between total level of certainty when interpreting an ECG and the participant's self-perceived proficiency (r =0.58,P = b.001). Before interpreting the ECGs, the participants were asked to report whether they were interested in pursuing a career in cardiology. Eight (15%) participants expressed a definite interest in a cardiology career. Eighteen (35%) were unsure and 26 (50%) were not interested in a career in cardiology. There was a significant difference (P =.01) in the total score achieved between the group interested in a career in cardiology (mean, 12.4 ± 3.4) and the other 2 groups (mean, 9.2 ± 3.8). Of the 2 PGY-1 residents who achieved the highest total score, one expressed a definite interest in a career in cardiology and the other was not sure. The lowest scores were attained by 2 PGY- 1 residents who expressed no interest in a career in cardiology. Most (87%) of the participants reported feeling they had received insufficient training before commencing their residency. Only 1 participant thought that his ECG training was sufficient and achieved a total score of 10 of 20. Discussion Fig. 1. Total scores. In this study, the overall accuracy rate of ECG interpretation by PGY-1 residents was low. The ECGs were specifically chosen as examples of conditions that medicine PGY-1 residents should be able to recognize by the start of

4 696 D. Eslava et al. / Journal of Electrocardiology 42 (2009) Table 3 Certainty for each ECG No. Diagnosis 100% Certainty, 75% Certainty, 50% Certainty, 25% Certainty, 0% Certainty, 1. AMI 5 (10) 17 (33) 18 (36) 8 (15) 4 (8) 2. Sinus bradycardia 4 (8) 11 (21) 18 (35) 15 (29) 4 (8) 3. VT 2 (4) 11 (21) 17 (33) 15 (29) 7 (13) 4. LVH 2 (4) 11 (21) 20 (39) 12 (23) 7 (13) 5. SVT 1 (2) 11 (21) 20 (39) 15 (29) 11 (21) 6. Atrial flutter 7 (13) 21 (40) 14 (27) 5 (10) 5 (10) 7. Wolf-Parkinson-White 2 (4) 11 (21) 10 (19) 15 (28) 14 (27) 8. Complete (3rd-degree A-V) block 1 (2) 10 (19) 20 (38) 9 (17) 12 (23) 9. Acute pericarditis 2 (4) 5 (10) 18 (35) 15 (29) 12 (23) 10. 2nd-degree A-V block type I 3 (6) 17 (33) 16 (31) 9 (17) 7 (13) their training. The ideal standard would be a score of 20 (100%), although an error rate of 20% to 30% would probably be acceptable. A systematic review published in 2003 that included 12 articles demonstrated that resident physicians detected 36% to 80% of ECG diagnoses as determined by experts. 8 The present study results were consistent with these findings. STsegment elevation myocardial infarction (MI) was correctly diagnosed by 83% of the participants, which was also consistent with several studies that showed that noncardiologist identified 87% to 100% of ECGs showing AMI. 8 Few studies have investigated ECG interpretation by resident physicians. Common errors have been a failure to recognize heart block, acute posterior MI, and supraventricular dysrhythmia. 9 In the present study, AMI was missed by 10%, VT was missed by 40%, and complete heart block was missed by 87%. In a study by Gillespie et al, 10 more than 50% of residents failed to recognize heart block and posterior MI when interpreting ECGs. The level of certainty when diagnosing critical ECGs such as AMI, VT, and complete heart block was also very low (10%, 4%, and 2%, respectively). The overall level of certainty about diagnoses was low, with no more than 13% of the participants being definite about their answers on any ECG. Most participants were not even certain of their diagnosis of sinus bradycardia ECG. Only 22 (42%) of the participants were able to correctly diagnose the ECG representing sinus bradycardia, and only 4 (8%) were completely certain of the diagnosis. These results indicate that PGY-1 residents are poor at interpreting ECGs and are aware of their limitations. Male participants tended to be more certain about their answers than females, but did not score higher overall. This perhaps was due to the poor correlation between the level of certainty and likelihood of being correct. This may also reflect overconfidence on behalf of men and a lack of confidence in women. Another possible interpretation is that women perhaps are more realistic about their skills than men. The results demonstrated a lack of confidence in diagnostic ability among PGY-1 residents. This is supported by the finding that only 9 (17%) participants thought they were good at interpreting ECGs. A self-reported proficiency score between 6 and 8 out of 10 was considered to be adequate or good at interpreting ECGs. No participant reported being excellent at interpreting ECGs. Proficiency in interpreting cardiac rhythms is a prerequisite skill in many areas especially in those practicing IM, 11 but it is also important in other areas such as emergency department. However, a limited number of studies have shown that residents are not proficient in interpreting ECGs. Electrocardiographic abnormalities may be the first indication of ischemia, metabolic and electrolyte abnormalities, and therapeutic or toxic effects of drugs or devices. Misinterpretation of an ECG can lead to unnecessary therapies and procedures and inappropriate clinical decisions. In addition, misinterpretation of ECGs of lifethreatening cardiac events, such as MI, VT, and complete heart block, has the potential for significant morbidity and mortality. Although the overall score was low, the results are consistent with a previous study 12 that found an independent correlation between an interest in a cardiology career and increased ECG competency. Presumably, residents interested in a cardiology career are more motivated to seek additional ECG training opportunities. They may also engage in more self-study of ECGs. 12 When assessing whether the participants thought the amount of their formal training in ECG competency was adequate, only 1 participant thought he had received an adequate level of ECG education. It is possible, however, that we induced such a high percentage rate of No responses to this question by formulating this question in a Yes, No, or Unsure answer format. One can argue that this question design limits the possible answers to this question and that perhaps a range of answer options could have produced a more accurate result. However, only 6 participants responded Unsure. It is possible that the major cause of poor performance among graduates of house staff programs is the decline in electrocardiography teaching. Thus, ECG training is an essential part of graduate medical education. On July 1, 2007, the Accreditation Council for Graduate Medical Education Residency Review Committee released the updated Program Requirements for Residency Education in Internal Medicine. In the section Procedures and technical skills Interpretative skills of this report, it is stated that All residents must develop competency in the interpretation of ECGs. 11 However, the meaning of competency was not specifically defined by the Residency Review Committee nor has it specified how to achieve this goal. Due to the lack of

5 D. Eslava et al. / Journal of Electrocardiology 42 (2009) evidence-based literature, it is unclear how to achieve, assess, and maintain competency in ECG interpretation. Several uncontrolled studies of residents and students showed improvement in ECG interpretation skills after structured ECG interpretation seminars. 8 A 2001 statement by the American College of Cardiology/American Heart Association recommended interpretation of 500 supervised ECG tracings during initial training, using standardized testing in ECG interpretation to confirm initial competency and interpreting 100 ECGs yearly to maintain competency. An earlier 1995 edition of the same guideline recommended 800 interpretations to attain initial competency in ECG interpretation. These tracings must include examples of common and critical scenarios one should be able to recognize. Both of these guidelines were created through expert consensus, but neither provided evidence-based data to support their conclusions. Further research is needed to find optimal methods to improve ECG interpretation competency. These methods must integrate physician skills to appropriately order ECGs, to recognize common normal and abnormal tracings, and to understand criteria for therapy decisions based on ECG interpretation. 6,8 Limitations A weakness of this study was that it did not include the participants' level of ECG education. This study evaluated whether the participant felt he had received adequate ECG interpretation training during medical school but did not assess the type and extent of such. This information would have been useful to correlate formal ECG training and the level of confidence and proficiency when interpreting an ECG. This study was conducted in a large university hospital IM training program involving first-year residents of diverse medical training backgrounds. This study did not include the data regarding how many different medical schools were represented and the percentage of US versus foreign medical schools. This is a small study that includes only the results of one institution, and therefore, it is not necessarily representative of the nation as a whole. Conclusions First-postgraduate-year residents at the onset of their IM training demonstrated overall low proficiency and a lack of confidence when interpreting ECGs. However, this study does not indicate their ECG interpretative skills at the end of their training. Nearly all participants perceived that their previous ECG training was insufficient. The findings of this study reinforce the need for increased ECG teaching in the undergraduate curriculum. Perhaps residency training programs should assess the new PGY-1 residents' ECG interpretation proficiency and provide remedial training to those who need it. It is important that training programs emphasize that PGY-1 residents consult with their senior house officers before making therapeutic decisions based on their own interpretation of an ECG. This study should stimulate strategies to achieve and formally assess competency in the interpretation of ECGs as well as evaluate the interpretative skills of IM residents at the end of their training. References 1. Hurst JW. The interpretation of electrocardiograms: pretense or welldeveloped skill? Cardiol Clin 2006;24: Fisch C, Ryan TJ, Williams SV, et al. Clinical competence in electrocardiography. Circulation 1995;91: Fisch C. Evolution of the clinical electrocardiogram. J Am Coll Cardiol 1989;14: Kadish AH, Buxton AE, Kennedy HL, et al. ACC/AHA clinical competence statement on electrocardiography and ambulatory electrocardiography. Circulation 2001;104: Vergara C. EKG rhythm interpretation patterns of medical interns: a need assessment test. Conn Med 2003;67: Salerno SM, Alguire PC, Waxman HS. Competency in interpretation of 12-lead electrocardiograms: recommendations from the American College of Physicians. Ann Intern Med 2003;138: Hatala R, Norman GR, Brooks LR. Impact of a clinical scenario on accuracy of electrocardiogram interpretation. J Gen Intern Med 1999;14: Salerno SM, Alguire PC, Waxman HS. Competency in interpretation of 12-lead electrocardiograms: a summary and appraisal of published evidence. Ann Intern Med 2003;138: Trzeciak S, Erickson T, Bunney B, et al. Variation in patient management based on ECG interpretation by emergency medicine and internal medicine residents. Am J Emerg Med 2002;20: Gillespie ND, Brett CT, Morrison WG, et al. Interpretation of the emergency electrocardiogram by junior hospital doctors. J Accid Emerg Med 1996;13: ACGME Program requirements for residency education in internal medicine. Effect July 1, Berger JS, Eisen L, Nozad V, et al. Competency in electrocardiogram interpretation among internal medicine and emergency medicine residents. Am J Med 2005;118:873.