Rationale: Acute myocardial infarction is a rare complication of carbon monoxide poisoning. there is often no chest pain and other typical manifestations. We report a patient with mild carbon monoxide poisoning who had acute dyspnea as the earliest symptom and was later diagnosed with non-ST elevation myocardial infarction (NSTEMI) and acute left heart failure. Patient concerns: A 73-year-old woman complained of dizziness and fatigue with shortness of breath after carbon monoxide intoxication. Diagnoses: This patient had a clear history of carbon monoxide poisoning, acute respiratory distress, bilateral lung dry and moist rale, chest X-ray showed bilateral pulmonary edema, Electrocardiograph indicated general depression of the ST segment of the leads in the chest, cardiac troponin I (CTNI) increased progressively, cardiac ultrasonography indicated abnormal ventricular wall movement, coronary angiography suggested left main trunk and 3-vessel lesions, suggesting diagnosis acute carbon monoxide poisoning, acute coronary syndrome, acute left heart failure. Interventions: She was treated with a high concentration of oxygen, an inhibitor of platelet aggregation (aspirin plus clopidogrel), an anticoagulant (low molecular weight heparin), an antimicrobial (ceftizoxime), an expectorant (mucosolvan), diuresis (furosemide and spironolactone), and myocardial support (Metoprolol). Coronary angiography and stent placement were performed 8 days later. Outcome: On the 10th day after onset of the condition, echocardiography was performed, which showed that cardiac function was improved. Mild segmental wall motion abnormality was observed on echocardiography. After 14 days, the patient had recovered well and was discharged without chest tightness, chest pain, dizziness, headache, or unresponsiveness. Lessons: This case suggests that the symptoms of carbon monoxide poisoning are complex and diverse. It can be manifested as a primary hypoxic symptom, or cause the exacerbation of underlying diseases due to hypoxia. Therefore, patients with carbon monoxide poisoning should actively seek comprehensive cardiac examination to ensure early diagnosis. Whenever necessary, coronary angiography and stent implantation should be performed to improve the likelihood of the patient's survival.
