Catheterization laboratory activations and time intervals for patients with pre-hospital ECGs

Objective. The use of pre-hospital ECGs (PH-ECG) reduces time to reperfusion for patients with ST-segment elevation myocardial infarction (STEMI). The feasibility of reperfusion therapy within 60minutes for hospitals with 24/7 PCI capability has been questioned, and current guidelines have set time targets to 90minutes. Our primary objective was to investigate the proportion of false-positive catheterization laboratory activations by PH-ECG. Our secondary objective was to describe the time intervals from first medical contact to reperfusion and to establish the proportion of patients receiving reperfusion within 60minutes. Design. A retrospective cohort study among 4298 patients for whom a PH-ECG was transmitted to the investigating hospital, mainly due to chest pain, during 2013 were included. Results. Among patients with PH-ECGs, 139 (3.2%) patients had a STEMI. There were 115 pre-hospital catheterization laboratory activations among which 16% (95% confidence interval 10-23) were false-positive for STEMI. The median total time from emergency call to arterial puncture was 76minutes. The target of PCI within 60minutes was met in 83% of the cases. The time from EMS arrival to PH-ECG was 20minutes for female patients and 13minutes for male patients (p<.001), and only 16% had a PH-ECG within 10minutes from Emergency Medical Service arrival. Conclusion. The rate of false-positive catheterization laboratory activations based on pre-hospital ECGs was low and the target of PCI within 60minutes is achievable for a majority of patients. Efforts should be made to reduce the time from ambulance arrival to PH-ECG transmission, especially for female patients.