Journal of Thrombosis and Thrombolysis

, Volume 15, Issue 3, pp 131–140

Observer Variability in ECG Interpretation for Thrombolysis Eligibility: Experience and Context Matter


  • David Massel
    • Department of Medicine, London Health Sciences CentreUniversity of Western Ontario

DOI: 10.1023/B:THRO.0000011368.55165.97

Cite this article as:
Massel, D. J Thromb Thrombolysis (2003) 15: 131. doi:10.1023/B:THRO.0000011368.55165.97


Background: Despite the known benefit of thrombolysis it remains underutilized among eligible patients with acute myocardial infarction. We sought to determine whether potential errors in ECG interpretation might be a contributing factor and to what extent clinical history, a checklist outlining recognized inclusion criteria and a computerized interpretation would influence reliability and accuracy.

Methods: Seventy-five ECGs were interpreted on 8 separate occasions by 9 clinicians (3 cardiologists, 3 cardiology fellows, 3 medical residents) according to a 2 × 2 × 2 factorial design.

Results: The overall level of agreement among all raters was substantial with a kappa (κ) of 70.4%. Intra-observer ECG reading reliability was stronger among cardiologists (CC) as compared with cardiology fellows (CF) and medical residents (MR). Similarly, inter-observer reliability was substantial to very good and a gradient was seen with greater reliability among CC, followed by CF, then MR (P = 0.0013). CC recommended thrombolysis significantly more frequently (p < 0.001) than either CF or MR. Trainees were biased by the presence of a computerized ECG interpretation resulting in a decision to recommend thrombolysis administration less often.

Conclusion: The reliability of ECG interpretation for deciding to administer thrombolysis was substantial; there was a gradient from lowest to highest commensurate with training and experience. Errors in thrombolysis eligibility are influenced by clinical history and the presence of a computerized ECG interpretation among less experienced clinicians.

acute myocardial infarctionthrombolysiselectrocardiographycomputerized ECG interpretation

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© Kluwer Academic Publishers 2003