Observer variability in ECG interpretation for thrombolysis eligibility: experience and context matter.
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 x 2 x 2 factorial design.


RESULTS
The overall level of agreement among all raters was substantial with a kappa (kappa) 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.


CONCLUSIONS
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.
Massel
David
D
Department of Medicine, London Health Sciences Centre, University of Western Ontario, Room 205 Colborne Building, Victoria Campus, 375 South Street, London, Ontario, Canada N6A 4G5. dmassel@lhsc.on.ca
D003253:Consultants; D003657:Decision Making; D003936:Diagnosis, Computer-Assisted; D003951:Diagnostic Errors; D004562:Electrocardiography / Q000592:standards*; D006801:Humans; D008503:Medical Staff; D015588:Observer Variation; D018579:Patient Selection; D015912:Thrombolytic Therapy / Q000706:statistics & numerical data*