What is the accuracy of Electrocardiogram (EKG) readings?

Accuracy of Electrocardiogram (EKG) Readings

The accuracy of EKG readings varies significantly based on multiple factors including technical aspects, interpreter expertise, and clinical context, with computer interpretation alone having an error rate of approximately 10-15% in abnormal EKGs. 1

Technical Factors Affecting EKG Accuracy

• The high-frequency response of the EKG machine significantly impacts accuracy, with a minimum recommended cutoff of 150 Hz for adults and adolescents and 250 Hz for children to maintain diagnostic precision 2
• Inadequate high-frequency response results in systematic underestimation of signal amplitude and smoothing of important features like Q waves and notched components within the QRS complex 2
• Digital electrocardiographs improve measurement reproducibility compared to analog tracings by creating representative templates from selected, accurately aligned complexes 2
• Noise in EKG signals can significantly affect measurements of duration and compromise the tradeoff between sensitivity and specificity for diagnostic criteria 2
• Electrode misplacement, particularly of precordial leads, is a common technical error that can significantly alter EKG interpretation and lead to false diagnoses 3

Interpreter Factors Affecting EKG Accuracy

• Computer interpretation alone is not recognized as a properly interpreted EKG according to guidelines; physician review is essential 2
• In a study of computer EKG interpretation, significant disagreements between computer and cardiologists occurred in 9.9% of all EKGs and 15.9% of abnormal EKGs 1
• The most frequent errors in computer EKG interpretation (86.4% of all errors) are related to arrhythmias, conduction disorders, and electronic pacemakers 1
• Computer diagnosis of life-threatening conditions such as acute myocardial infarction or high-degree AV blocks are frequently inaccurate (40.7% and 75.0% errors, respectively) 1
• Experience level significantly impacts interpretation accuracy, with physicians having more than 12 years of experience achieving exact matches in 75% of cases compared to 67% for those with 0-6 years of experience 4

Clinical Context Impact on Accuracy

• Providing correct clinical history improves EKG interpretation accuracy by 4-12% compared to no history, while misleading history reduces accuracy by 5-25% depending on expertise level 5
• Clinical history affects the frequency of identifying EKG features consistent with both correct and alternative diagnoses across all levels of physician expertise 5
• The ECG should always be interpreted in the context of the patient's clinical presentation, as the same finding may have different implications depending on symptoms 3
• Noncardiologists are more influenced by patient history in interpreting EKGs than cardiologists, making clinical context particularly important 3

Advanced Technologies Improving Accuracy

• Deep learning approaches for automated multilabel diagnosis of heart rhythm or conduction abnormalities have demonstrated better-than-human accuracy, with an exact match in 80% of EKGs compared to 67-75% for physicians depending on experience level 4
• Self-attention artificial intelligence auto-encoder algorithms with modified Kalman filter pre-processing have achieved up to 99.71% accuracy in cardiac arrhythmia classification 6
• Artificial intelligence models have demonstrated a mean area under the ROC curve of 0.983, with sensitivity of 0.867 and specificity of 0.995 for arrhythmia detection 4

Diagnostic Criteria and Their Performance

• The Seattle criteria demonstrated the highest overall accuracy for identifying high-risk cardiovascular conditions in athletes, with significantly better discriminative performance than the International criteria 7
• Different diagnostic criteria show varying sensitivity and specificity, with the Seattle criteria showing a lower false-positive rate compared to ESC criteria in master athletes 7
• The ECG is the only practical, noninvasive method of recording and analyzing abnormalities of cardiac rhythm, but diagnoses of structural or pathophysiologic changes are made by inference and therefore subject to error 2

Best Practices for Maximizing EKG Accuracy

• Always have EKGs interpreted by a qualified physician rather than relying solely on computer interpretation 2
• Compare current EKGs with previous recordings when available to identify important changes 3
• Consider the clinical context when interpreting EKGs, as this significantly impacts diagnostic accuracy 5
• Ensure proper electrode placement and appropriate filter settings to minimize technical errors 3
• Maintain continuing medical education through seminars or self-assessment programs to keep EKG interpretation skills current 3