Electrocardiographic findings of carbon monoxide intoxication; two cases

Abstract

Carbon monoxide (CO) poisoning is a life threatening emergency. Oxygen delivery to tissues is reduced and hypoxia develops. Most affected systems are the central nervous system and cardiovascular system. For the diagnosis of CO poisoning, first poisoning should be suspected and then blood carboxyhaemoglobin (COHb) levels should be measured. For cardiovascular evaluation ECG is required. Case 1: A 56-year-old male patient admitted to ED with complaints of syncope, headache, dizziness and blurred vision. Patient was mentally confused and on ECG sinus tachycardia was present (Fig. 1). On blood gas analysis COHb value was measured 33.3%. Due to syncope and ECG changes hyperbaric oxygen (HBO) therapy initiated. After the treatment, COHb value was measured 4.5% and ECG showed normal sinus rhythm. Patient was discharged with recommendations. Case 2: An unconscious 36-year-old female patient admitted to ED with a diagnosis of CO poisoning. ECG revealed ST depression on DII-DIII-AVF leads (Fig. 2) and elevated troponin I (0.1 ng/ml) and CK-MB (47 U/L) values were determined. On blood gas analysis, COHb value was measured 39.8%. HBO therapy initiated. After HBO therapy patient was conscious and for further follow-up patient was admitted to intensive care unit. Discussion and Conclusion: Although there is no classic ”carbon monoxide” ECG pattern, sinus tachycardia and ST-T depressions are the most common ECG findings. Even a small amount of exposure to CO can cause myocardial infarction, especially in patients with coronary artery disease. Patients admitting to ED with chest pain and ECG changes may be considered as a possible CO poisoning and patients with CO poisoning must be carefully evaluated for cardiovascular disease.