Can you read an electrocardiogram (ECG)?

Can I Read ECG?

If you have completed residency training in internal medicine, family medicine, or emergency medicine with board certification and Advanced Cardiac Life Support (ACLS) training, you are competent to interpret ECGs at the bedside in routine and emergency settings. 1

Training Requirements for ECG Competency

For Bedside Interpretation in Clinical Practice

• Completion of residency training plus board certification and ACLS certification provides objective documentation of competency for interpreting ECGs in routine and emergency settings. 1

• The American College of Cardiology recommends interpreting and reviewing 800 ECGs within a 3-year training period under experienced faculty supervision, reflecting a wide variety of clinical situations and abnormalities. 1

• Cardiologists should read approximately 3,500 ECGs during fellowship training according to the Bethesda Conference recommendations. 1

For Formal ECG Reading Privileges (Without Clinical Context)

• When interpreting ECGs for patients not under your direct care, you need additional documentation beyond residency and board certification—either extensive experience or passing a valid standardized examination. 1

• Noncardiologists are more influenced by patient history and automated computer interpretations than cardiologists when reading ECGs, and demonstrate lower accuracy on standardized examinations when minimal clinical history is provided. 1

• Cardiologists show greater accuracy than noncardiologists in ECG interpretation during standardized testing with minimal history. 1

Current Physician Performance Data

• Across all training levels, median ECG interpretation accuracy is only 54% on pretraining assessments and 67% after training, indicating widespread deficiencies even among practicing physicians. 2

• Pooled accuracy rates vary significantly by training level: medical students 42%, residents 55.8%, practicing physicians 68.5%, and cardiologists 74.9%. 2

• These accuracy rates demonstrate that physicians at all training levels have substantial deficiencies in ECG interpretation, even after educational interventions. 2

Maintaining Competency Over Time

• If you read ECGs infrequently, you must engage in periodic self-study or continuing medical education through seminars or self-assessment programs to maintain current skills. 1

• No data exist to recommend a specific yearly minimum number of ECG interpretations or continuing medical education hours to maintain competency. 1

• Random sampling of your ECG interpretations should be reviewed periodically by independent experts as part of quality assurance programs to confirm continued competence. 1

• The American College of Cardiology offers self-assessment programs in electrocardiography for ongoing skill maintenance. 1

Critical Limitations and Pitfalls

Computer Interpretation

• All computer ECG interpretations must be verified by a qualified physician—computer programs provide accurate heart rate, intervals, and axes, but interpretations of rhythm disturbances, ischemia, or infarction require careful physician over-reading. 1, 3, 4

• Computer interpretations are helpful adjuncts but never substitutes for physician interpretation. 3

Clinical Context Dependency

• Never interpret ECGs in isolation—you must integrate clinical data, provide differential diagnosis, and compare with previous tracings, as the same ECG pattern may occur in different pathophysiologic states. 1, 3

• The ECG has 76% sensitivity and 88% specificity for diagnosing acute cardiac ischemia in chest pain patients, but clinical signs and symptoms alone have only 35-38% sensitivity and 28-91% specificity without ECG and biomarkers. 3

• An incorrect ECG diagnosis can have significant undesirable medical and legal consequences. 1

Systematic Interpretation Approach

When interpreting ECGs, follow this algorithmic framework:

• Verify proper electrode placement and adequate filtering settings before interpretation, as misplaced precordial leads can significantly alter findings and lead to false diagnoses. 3

• Calculate heart rate, identify underlying rhythm by confirming P wave before each QRS with consistent PR interval. 3

• Measure PR interval (normal 120-200 ms), QRS duration (normal <120 ms), and corrected QT interval (QTc <450 ms for men, <460 ms for women). 3

• Determine electrical axis using leads I and aVF: normal when both positive (+90° to -30°). 3

• Examine for ST-segment elevation (>0.1 mV in limb leads or >0.15-0.2 mV in precordial leads) indicating acute injury requiring emergent reperfusion. 3

• Identify pathological Q waves (>0.04 seconds or >25% of R wave amplitude) suggesting prior myocardial infarction. 3

• Note the location of abnormalities to determine affected coronary territory for catheterization lab activation decisions. 3