Although cardiac troponin I (cTnI) elevations during acute pulmonary embolism (PE) are predictive of in-hospital death, it is not clear whether cTnI measurements at emergency department (ED) admission are predictive of the occurrence of hypotension. The study subjects included all consecutive patients with acute PE (diagnosed by chest computed tomography angiography) in the ED between January 2006 and December 2011. All underwent cTnI tests at ED admission and were divided into two groups based on the occurrence of hypotension within 24 h. Of 457 stable patients with acute PE who were admitted to the ED during the study period, 301 patients were included. Within 24 h of hospitalization, 27 (9.0%) developed hypotension. The patients who developed hypotension had a significantly higher mean cTnI concentration than did the remaining patients (1.01 vs. 0.14 ng/mL, P < 0.00). They were also more likely to be treated with thrombolytic therapy and had higher 28-day and 6-month mortality rates. Cardiac TnI elevation (>0.05 ng/mL) at ED admission was a strong predictor of the development of hypotension within 24 h (odds ratio, 8.2; 95% confidence interval, 2.6-26.1; P = 0.00). The sensitivity, specificity, positive predictive value, and negative predictive value of elevated cTnI were 85%, 66%, 20%, and 98%, respectively. This study suggests that a normal cTnI nearly rules out subsequent development of hypotension within 24 h. This may help to select those patients who would benefit most from intensive clinical surveillance and escalated treatment.