BACKGROUND/PURPOSE: We tested the hypothesis that paramedic recognition of ST-elevation myocardial infarction (STEMI) and cardiologist activation of the cardiac catheterization laboratory without transmission of the electrocardiogram reduces door-to-balloon times. METHODS: We studied a consecutive series of patients suspected to have STEMI who were taken to the cardiac catheterization laboratory in the 6-month period before hotline implementation (historical controls) and during the first year of hotline use (intervention group, hotline; emergency medical service patients without hotline, concurrent controls). RESULTS: Emergency medical services activated the hotline 47 times, and 25 patients were subsequently taken to the catheterization laboratory. Patients who received PCI involving hotline use (n = 20) had significantly shorter door-to-balloon times (58 minutes; 25th-75th percentile, 52-73 minutes) than historical controls (n = 15) (112 minutes; 25th-75th percentile, 81-137; P < .0001) and concurrent controls (n = 15) (92 minutes; 25th-75th percentile, 76-112; P = .019). CONCLUSIONS: Paramedic transtelephonic communication to cardiologist of clinical and electrocardiogram assessment resulted in a 54-minute reduction in door-to-balloon time for patients with STEMI.