PURPOSE: The aim of this study was to evaluate the cardiovascular manifestations and clinical course in patients with acute carbon monoxide poisoning. METHODS: A retrospective study was conducted over a 36 month period on consecutive patients who visited an emergency medical center and were diagnosed with acute carbon monoxide poisoning. A standardized data extraction protocol was performed on the selected patients. RESULTS: A total of 293 patients were selected during the study period. Cardiac manifestations were observed in 35.2% (n=103) of the patients: hypotension in 11 patients (3.8%), ECG abnormalities in 44 patients (15.0%) and cardiac enzyme abnormalities in 103 patients (35.2%). Echocardiography was performed on 56 patients with cardiac toxicity: 12 patients had abnormal results (5 patients with global hypokinesia and 7 patients with regional wall akinesia). Five patients died within 3 hours after ED admission, and the remaining patientswere discharged alive. At 3 months after discharge, none of these patients had died.The SOFA scores in the severe cardiac toxicity group and non-severe cardiac toxicity group at the time of arrival were 2.53+/-2.29 and 2.19+/-2.12, respectively (p=0.860). CONCLUSION: Cardiovascular manifestations occurafter acute CO poisoning at arateof 35.2%. Even those with severe cardiovascular toxicity recovered well within 10 days after admission. Therefore, the importance of cardiac toxicity after acute CO poisoning is not significant initself in the clinical course, and the short-term prognosis of cardiac toxicityis unlikely to be unfavorable in acute CO poisoning.