Prehospital ECGs Valuable and Underused
Canto and colleagues retrospectively compared the characteristics and outcomes in patients with a prehospital ECG (3,768) to those without a prehospital ECG (63,227) in the National Registry of Myocardial Infarction 2 data base. Self-transported patients were excluded from the study. The median time from symptom onset until hospital arrival was longer among those having a prehospital ECG (152 vs. 91 min). Once in the hospital, the prehospital ECG group experienced a shorter median time to the initiation of either thrombolysis (30 vs. 40 min) or primary angioplasty (92 vs. 115 min). The prehospital ECG group was also more likely to receive thrombolytic therapy (43% vs. 37%) and to undergo primary angioplasty (11% vs. 7%). Even after adjusting for baseline variation, a statistically significant in-hospital mortality remained -- 8% in patients with a prehospital ECG and 12% in those without a prehospital ECG. The authors concluded: "The prehospital ECG is infrequently utilized for diagnosing myocardial infarction...[It] may potentially influence the management of patients with acute myocardial infarction through wider, faster in-hospital utilization of reperfusion strategies and greater usage of invasive procedures, factors that may possibly reduce short-term mortality. Efforts to implement the prehospital ECG more widely and more rapidly may be indicated."
This is the first large-scale study of utilization of prehospital ECG that I have seen. Previous studies have documented that "door to needle time" is reduced by the prehospital 12-lead despite increased field time, but not in such a huge group of patients. The present study does not discern whether the longer symptom-onset-to-hospital-arrival time was due to EMS factors or other reasons. Thus, it’s difficult to directly indict "scene time" for the ECG as the culprit. I found the 5% incidence of prehospital ECG to be incredibly low, especially when one considers that it appears to make a significant impact on treatment, and on in-hospital mortality. Studies like this should fuel additional attempts to increase the use of 12-lead ECGs in the field.