Outcomes by day and night for patients bypassing the emergency department presenting with ST-segment elevation myocardial infarction identified with a pre-hospital electrocardiogram.

Background: Pre-hospital ECG and emergency department (ED) bypass direct to the catheter laboratory may optimize reperfusion times for patients with ST-segment elevation myocardial infarction. Questions remain over feasibility and safety during off hours.

Aims: To determine if presenting time of day is associated with differences in in-hospital and 30-day mortality and key reperfusion times.

Methods/results: Seven hundred and twenty consecutive patients with STEMI triaged directly from the field to the catheter laboratory between June 2004-May 2013. Vital status was reported as of August 2013. The mean age was 65 ± 14 years, and 75.1% were male. Overall mortality (in-hospital/30 days) did not significantly differ for patients (3.4% in hours and 3.1% off hours; P = N/S). Symptom onset-to-arrival to the heart attack was non-significantly lower (100 minutes off hours (IQR 78-174) versus 110 minutes in hours (IQR 75-199), P = N/S). Call-to-balloon time was not significantly affected by the time of presentation: 150 min in hours (IQR 111-239) versus 154 minutes during off hours (IQR 115-225) P = N/S. Overall door-to-balloon time was 36 minutes (IQR 25-51), 34 minutes in hours (IQR 24-49) versus 40 minutes off hours (IQR 29-55) P = N/S. The overall false positive activation rate was only 13.1%, (in hours 12.2% vs. off hours 14.6%, respectively, P = N/S).

Conclusions: In a unit with an established field triage system facilitating ED bypass, reperfusion times and mortality are not significantly influenced by whether the patient presents during standard working hours or outside of these hours.