EKG to Activation - A Quality, Quality Metric?
/McLaren, J. T. T., Kapoor, M., Yi, S. L. & Chartier, L. B. Using ECG-To-Activation Time to Assess Emergency Physicians’ Diagnostic Time for Acute Coronary Occlusion. J Emerg Medicine 60, 25–34 (2021).
Background
Time is myocardium, and minimizing door-to-activation time improves outcomes in patients with acute coronary occlusion. Door-to-ECG time was proposed by the authors as a new quality metric to assess emergency physicians’ role in shortening the door-to-activation and door-to-balloon times.
Methods
This was a retrospective chart review at 2 urban academic centers in Toronto. The authors looked at all cath lab activations be emergency department physicians from January 2016 through December 2018. All patients who went to the cath lab after being activated from the inpatient wards or from the field and other hospitals were excluded.
EKGS were analyzed by two physicians who were blinded to all patient information other than age and sex. The EKGs were classified as STEMI, STEMI equivalent, EKGs that met criteria for certain rules of subtle occlusion, and no identifiable sign of occlusion.
The researchers then measured time from EKG to cath lab activation as documented in the medical record.
Results
There were 244 cath lab activations that met inclusion criteria during the study period. 177 of these activations had culprit lesions, and 67 had no cultprit lesions. 6.6% of the activations had no acute MI and no culprit lesion, representing EKGs with erroneous interpretation.
For patients with culprit lesions median ETA time was 16 minutes. For patients with EKGs labeled “STEMI” by automated interpretation, ETA time was 6.5 minutes. This is contrasted to an ETA time of 66 minutes for EKGs without an automated interpretation of “STEMI.”
For all EKGs classified as STEMI by the physicians analyzing EKGs, ETA time was 8 minutes. For STEMI-equivalents, ETA time was 32 minutes. For rules for subtle occlusion, ETA time was 89 minutes and this was not statistically significantly different than the ETA time for EKGs with no diagnostic sign of occlusion, which was 68 minutes.
Discussion
ETA time was proposed by the authors as a quality metric for emergency physicians for ED quality improvement initiatives and for emergency physicians and cardiologists to set new quality benchmarks. It is important to note that improving ETA time needs to be balanced against the risk of unnecessary cath lab activation.
Clearly, automated interpretation helps physicians make rapid decisions about cath lab activation, although the automated interpretation is not always accurate and only correctly labeled 82.3% of classic STEMI EKGs, 6.7% of STEMI-equivalents, and 10.3% of subtle occlusions.
It seems that physicians are good at identifying STEMIs since these had the shortest ETA time. However there was a significantly longer ETA time for STEMI equivalents, implying that these EKGs take longer for physicians to recognize. ETA time was equivalent for rules for subtle occlusion and no diagnostic signs of occlusion, which suggests that no one really knows the rules for subtle occlusion proposed by the authors.
Limitations
The authors acknowledged selection bias, since the study did not include canceled cath lab activation. There was also survivorship bias, since patients who died in the ED were not included. There was also significant misclassification bias due to exclusion of patients on the inpatient wards who did not have the cath lab activated in the ED but later went to the cath lab from the wards, likely leading to underestimation of missed occlusions.
Authorship
Written by: Emily Roblee, MD, PGY-3 University of Cincinnati, Department of Emergency Medicine
Editing and Posting by: Jeffery Hill, MD MEd
