BACKGROUND:

Rapid treatment of acute coronary syndromes (ACS) is important; causes of delay in emergency medical services care of ACS are poorly understood. METHODS AND RESULTS:

We performed an analysis of data from IMMEDIATE (Immediate Myocardial Metabolic Enhancement during Initial Assessment and Treatment in Emergency Care), a randomized controlled trial of emergency medical services treatment of people with symptoms suggesting ACS, using hierarchical multiple regression of elapsed time. Out-of-hospital ECGs were performed on 54,230 adults calling 9-1-1; 871 had presumed ACS, 303 of whom had ST-segment elevation myocardial infarction and underwent percutaneous coronary intervention. Women, participants with diabetes mellitus, and participants without previous cardiovascular disease waited longer to call 9-1-1 (by 28 minutes, P<0.01; 10 minutes, P=0.03; and 6 minutes, P=0.02, respectively), compared with their counterparts. Time from emergency medical services arrival to ECG was longer for women (1.5 minutes; P<0.01), older individuals (1.3 minutes; P<0.01), and those without a primary complaint of chest pain (3.5 minutes; P<0.01). On-scene times were longer for women (2 minutes; P<0.01) and older individuals (2 minutes; P<0.01). Older individuals and participants presenting on weekends and nights had longer door-to-balloon times (by 10, 14, and 11 minutes, respectively; P<0.01). Women and older individuals had longer total times (medical contact to balloon inflation: 16 minutes, P=0.01, and 9 minutes, P<0.01, respectively; symptom onset to balloon inflation: 31.5 minutes for women; P=0.02). CONCLUSIONS:

We found delays throughout ACS care, resulting in substantial differences in total times for women and older individuals. These delays may impact outcomes; a comprehensive approach to reduce delay is needed.