Objectives: The objectives were to compare the proportion of false-positive activations and intervention times between emergency department (ED) and field-based activation of the coronary catheterization laboratory (cath) team for emergency medical services (EMS) patients identified by out-of-hospital (OOH) 12-lead electrocardiogram (ECG) with ST-segment elevation myocardial infarction (STEMI).
Methods: This was a retrospective review of prospectively collected continuous quality improvement data at a single, urban, academic medical center. By protocol, weekday activation of the cath team occurred based on OOH notification of a computer-interpreted OOH ECG indicating potential STEMI. Night and weekend activation occurred at the discretion of the attending emergency physician (EP) after advanced ED notification and after patient arrival and assessment. Basic demographic information and cardiac risk factors were recorded, as well as door-to-balloon (DTB) and ultimate diagnosis.
Results: From May 2007 through March 2008, there were 23 field activations and 33 ED activations. There was no difference in demographic or clinical characteristics between the two groups. In the field activation group, 9/23 (39%) were false-positives, while 3/33 (9%) were false-positives in the ED activation group (30% higher absolute difference in the field activation group, 95% confidence interval [CI] = 8% to 52%, p = 0.02). OOH times and time spent in the ED were similar between the two groups. DTB times were 77 minutes for field activation and 68 minutes for ED activation, respectively (difference 9 minutes, 95% CI = -9 to 27).
Conclusions: Emergency physician activation of the cath team results in a lower proportion of false-positive activations without clearly sacrificing DTB time when compared to field activation based solely on the results of the OOH ECG.