Role of Electrocardiogram, Cardiac Biomarkers and Echocardiogram in Diagnosing Acute Carbon Monoxide Induced Myocardial Injury

Background: Carbon monoxide (CO) poisoning is a common accidental cause of toxicological morbidity and mortality worldwide.
Aim of this study: the aim of this study was to evaluate the cardiovascular manifestations of acute CO poisoning and the value of ECG changes, cardiac biomarkers (troponin I and CK-MB) determination and echocardiography in diagnosing cardiac damage in acute carbon monoxide poisoning cases.  Additionally, evaluate the impact of delayed time of hospital presentation and duration of exposure on these parameters.
Subjects & Methods: This is a cross-sectional study that was conducted on admitted patients with acute carbon monoxide poisoning to Toxicology Unit, Emergency Hospital, Tanta University in the period from the first of March 2014 to the end of September 2015. All patients were subjected to history taking and clinical examination. Additionally, ECG, echocardiogram, cardiac biomarkers (creatinephosphokinase CK-MB, and troponin I), and carboxyhemoglobin (COHb) levels were performed for all patients.
Result: the age of the studied patients ranged from 15-55 years, the delay time from 1.5-10 hours and the duration of exposure to CO ranged from 0.5 to 5 hours. The most common cardiovascular manifestations were tachycardia; occurred in 50.9% of the patients then dyspnea (24.6%), chest pain (12.3%) and lastly hypotension (10.5%). The ECG findings showed that 48.2% of the studied patients had sinus tachycardia, 5.4% had T-wave inversion or ST depression and combination of T-wave inversion and ST depression occurred in 3.6% of the patients. All patients who had ECG suggestive of cardiac ischemia had abnormal CPK-MB, troponin I and cardiac wall motion abnormalities in echocardiography. Furthermore, significant negative correlation between delay time and duration of exposure with Glasgow coma scale was evident as well as significant positive correlation between both ECG & echocardiographic changes and delayed presentation.
Conclusion: the present study revealed that sinus tachycardia was the most common cardiac manifestation of acute CO poisoning. ECG finding that suggested myocardial ischemia occurred in only 14.4% of the patients. Therefore, a baseline ECG should be routinely performed but, it is not necessary to routinely measure troponin I and do echocardiography.  But, it can be restricted to only cases with abnormal ECG findings.