Rates of Cardiac Catheterization Cancelation for ST Elevation Myocardial Infarction After Activation by Emergency Medical Services or Emergency Physicians: Results From the North Carolina Catheterization Laboratory Activation Registry (CLAR)

Study Questions:

What are the incidence and causes of false activation of the cardiac catheterization laboratory in patients with suspected ST-segment elevation myocardial infarction (STEMI)?


The authors studied catheterization laboratory activation at 14 primary angioplasty hospitals in North Carolina to determine the course of management, including the rate of inappropriate activation, between December 2008 and December 2009.


There were 3,973 activations during the study period, of which 29% were initiated by emergency medical technicians (EMTs) and the rest by emergency physicians. Activation was considered appropriate for 3,377 patients (85%), with 2,598 patients (76.9% of appropriate activations) receiving primary PCI. Catheterization laboratory activation was considered inappropriate in 15% (n = 596) of patients, with the most common reason being ECG reinterpretations (427 patients, 72%) or the patient not being a candidate for angiography (169 patients, 28%). Cancellation due to reinterpretation of ECGs was more common when activation was initiated by EMTs (6% of all activations) compared with emergency physicians (4.6%).


The authors concluded that there was a low rate of inappropriate activation of the catheterization laboratory for STEMI in this state-wide program.


In efforts to reduce time to reperfusion, there has been a nearly universal move toward activation of the catheterization laboratory by emergency room physicians or by EMTs in the field. It is not surprising that this has been accompanied by an increasing rate of false activations. This study suggests that false activations are not too frequent, although they do appear to be slightly increased when initiated by EMTs. These findings relate to a state-wide collaborative that has been actively working to improve STEMI care in North Carolina, and it is not clear if the same findings can be replicated in other geographic locales.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Emergency Medical Technicians, Incidence, Myocardial Infarction, Cardiology, Cardiac Catheterization, Catheterization, Cardiovascular Diseases, Electrocardiography, Angioplasty, North Carolina

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