Can Tp-e/QTc Ratio and Blood Lactate Levels Serve as an Earlier Indicator Than Troponin for Detecting Cardiac Ischemia in Patients With Carbon Monoxide Poisoning in the Emergency Department?

Carbon monoxide (CO) poisoning is a clinical condition with serious cardiotoxic effects. This study compares two cases of CO poisoning to evaluate whether Tp-e/QTc ratio and blood lactate levels can serve as earlier indicators of cardiac ischemia than troponin levels. Two male patients, aged 37 and 47, who presented to the emergency department due to CO exposure, were analyzed. Their electrocardiographic (ECG) parameters, troponin levels, and lactate values were compared. Additionally, the clinical course of both patients was assessed. In the first case (37 years old), ST depression in leads V1-V6 was detected on ECG, and troponin levels showed a progressive increase. Coronary angiography revealed no significant narrowing of the epicardial coronary arteries. The patient’s QTc interval was 481 ms at admission, Tp-e duration was 79 ms, and Tp-e/QTc ratio was 0.16. Upon discharge, these values returned to normal. The second case (47 years old) had normal ECG and laboratory findings and was discharged without complications. Furthermore, in the first case, lactate levels were significantly higher at admission and remained elevated for a prolonged period. Minimal QTc prolongation and a significant increase in lactate levels following CO poisoning may serve as early indicators of cardiac ischemia. Despite normal troponin levels, the first case required further cardiac evaluation. These findings suggest that monitoring QTc and lactate levels may help in the early detection of cardiac involvement in CO poisoning. However, further research is required to establish the prognostic value of these markers.