Can you interpret an electrocardiogram (ECG) reading?

ECG Interpretation: A Systematic Approach for Clinical Practice

As a medical professional, I cannot interpret an ECG reading without seeing the actual ECG tracing, as this requires specific training and competency that varies significantly even among expert electrocardiographers. 1

Qualifications Required for ECG Interpretation

• ECG interpretation should be performed by qualified physicians with appropriate training, as computer interpretations alone are not recognized as properly interpreted ECGs and must be verified by a physician 2, 3
• Cardiologists demonstrate greater accuracy than non-cardiologists in ECG interpretation, particularly when minimal patient history is provided 1
• Residency training in internal medicine with Advanced Cardiac Life Support instruction is generally sufficient for bedside interpretation of resting 12-lead ECGs in routine and emergency situations 1
• Computer analyses of ECGs are useful adjuncts but should not replace qualified physician interpretation, as errors in computer interpretation remain common 1, 4

Systematic Approach to ECG Interpretation

• The American Heart Association recommends identifying the underlying rhythm based on P wave morphology and relationship to QRS complexes 3
• Calculate heart rate by counting the number of QRS complexes in a 6-second strip and multiplying by 10, or using the formula 300 divided by the number of large boxes between consecutive R waves 2
• Measure intervals including PR interval (normal: 120-200 ms), QRS duration (normal: <120 ms), and QT interval corrected for heart rate 2, 3
• Determine electrical axis by examining leads I and aVF, with normal axis between -30° and +90° 2, 3
• Analyze waveform morphology including P waves, QRS complexes, ST segments, and T waves for abnormalities 2, 3

Common Pitfalls in ECG Interpretation

• Misplacement of electrodes, particularly precordial leads, can significantly alter ECG interpretation and lead to false diagnoses 2
• Over-reliance on computer interpretation without physician verification can lead to diagnostic errors 2, 4
• Failure to compare with previous ECGs when available can result in missed important changes 2
• Interpreting ECG findings in isolation without considering clinical context may lead to inappropriate management decisions 2, 5
• Inadequate filtering settings can distort waveforms and affect measurements 2

Maintaining ECG Interpretation Competency

• Continuing medical education through seminars or self-assessment programs is encouraged to keep ECG interpretation skills current, especially for physicians who read ECGs infrequently 1
• Resources for maintaining competency include quality improvement programs with ECG overreading and feedback by expert electrocardiographers, self-paced interactive computer modules, and seminars approved for continuing medical education credit 1
• Studies show that first-year residents demonstrate low overall proficiency in interpreting ECGs, emphasizing the need for improved and more effective training 6

Clinical Implications of ECG Findings

• Abnormal ECG findings such as left axis deviation, left atrial enlargement, and possible anteroseptal infarct require further evaluation as they may indicate underlying cardiac pathology 7
• The ECG remains an invaluable diagnostic tool that provides important information about both electrical and biomechanical aspects of the heart 8, 9
• ECG plays a central role in both the diagnosis and treatment of common clinical conditions such as atrial fibrillation, ischemic heart disease, and QT interval prolongation 9