For emergency department (ED) patients with cardiac chest pain, introduction of high-sensitivity troponin (hsTnT) pathways has been associated with reductions in length of stay of less than 1h. At two urban Canadian sites, we introduced hsTnT on January 26, 2016. While the prior diagnostic algorithm required troponin testing at 0 and 6h, serial hsTnT serial testing was conducted at 0 and 3h. We identified consecutive patients who presented with cardiac chest pain from January 1, 2015, to March 31, 2017, along with 30-day outcomes. The primary outcome was a missed 30-day major adverse cardiac event, (MACE) defined as death, revascularization, or readmission for myocardial infarction occurring in a patient-discharged home with a minimizing diagnosis and without cardiac-specific follow-up. Secondary outcomes included admission rate, ED length of stay, and MACE. We compared pre- and post- implementation periods using descriptive methods and repeated this analysis in patients with noncardiac chest pain. We collected 5585 patients with cardiac chest pain, (2678 pre- and 2907 post-introduction) and 434 had (7.8%, 95% CI 7.1 to 8.5%) MACE, with 1 missed MACE. (0.2%, 95% CI 0.04 to 1.3%). Admission rate was stable at 24.1% pre- and 23.7% while median length of stay decreased from 464 to 285 min, a difference of 179 min. (95% CI 61 to 228 min). For 11,611 patients with noncardiac chest pain, admission rate (9%) and length of stay (191 versus 193 min) remained constant. Implementation of hsTnT for evaluation of ED chest pain patients was safe and associated with a 3-h decrease in length of stay.