ECG Interpretation of STEMI: Who's the Expert?

Amal Mattu, MD


March 21, 2012


I was involved in a malpractice case a couple of years ago as a consultant. The case involved an emergency physician who was being sued for failure to make a rapid diagnosis of an ST-segment elevation myocardial infarction (STEMI). ST-segment elevation (STE) was clearly present on the ECG but he assumed it was due to a nonischemic cause. Eventually the diagnosis of STEMI was made, but the delay and resulting cardiomyopathy was the cause for legal action. The plaintiff expert who adamantly attested that the diagnosis should have been made from the start was a cardiologist. The STE, in his mind, was clearly, unquestionably due to STEMI. I honestly thought that the emergency physician's decision-making was very defensible. But I'm no cardiologist.

Cardiologists are often considered the experts in ECG interpretation and the final word in diagnosing the cause of STE on an ECG. Cardiologists are afforded the prerogative to cancel an activation of the cardiac catheterization lab if they disagree with an emergency physician's ECG interpretation; they are frequently consulted to provide a "final" diagnosis in equivocal cases when STE is noted on the ECG; and they are sometimes used as experts for ECG interpretation in malpractice cases against emergency physicians or other acute care providers. A cardiologist's ECG interpretation is often considered the gold standard upon which to base critical treatment decisions -- or upon which to retrospectively critique incorrect treatment decisions.

It's certainly reasonable to expect cardiologists in general to have greater knowledge regarding ECG interpretation than other specialists because they spend longer time in training than many other specialists, and detailed ECG interpretation is a core component of a cardiology fellow's training and board examination. However, "greater knowledge" does not equate to "expertise" or "gold standard." Current and recent studies have raised doubts about whether every cardiologist should be considered a "gold standard" for ECG interpretation and with regard to the accuracy of ECG interpretation by physicians in general.

Differentiating ST-Elevation Myocardial Infarction From Nonischemic ST-Elevation in Patients With Chest Pain

Tran V, Huang HD, Diez JG, et al
Am J Cardiol. 2011;108:1096-1101

Study Summary

The researchers collected 84 ECGs showing STE in at least 2 contiguous leads from a database of patients for whom catheterization lab activation had occurred because of presumed STEMI. Patients with left bundle branch block or ventricular rhythms were excluded. Final diagnoses were based on the combination of catheterization results, troponin rise and fall, and evolution of ECG findings. The ECGs were given to 7 "experienced interventional cardiologists" and they were asked to analyze the ECGs to determine whether they would recommend activation of the catheterization lab for presumed true STEMI. They were also told to assume the patients "had appropriate corresponding symptoms."

The results: Forty patients (48%) had true STEMI and 44 patients (52%) had nonischemic causes of STE (NISTE). The sensitivity among these cardiologists for detecting the true STEMIs ranged from 53% to 83% (mean 71%) and the specificity ranged from 32% to 86% (mean 63%). In other words, on average these experienced interventional cardiologists missed 29% of the STEMIs and incorrectly diagnosed STEMI in 37% of the cases of NISTE.


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