Evaluation of the Significance of Positive Troponin I in Patients With Methadone Toxicity

Background: Controversy continues surrounding the relationship between methadone and coronary artery disease (CAD). Given the evidence regarding methadone overdose and elevated high-sensitivity troponin I (hs-TnI) levels, we sought to determine whether elevated hs-TnI was associated with subtle CAD. Methods: This cross-sectional study was conducted on 100 cases with methadone overdose. Electrocardiography (ECG) was performed on day 1 after admission, and QTc intervals and ST-T segment changes were recorded. The venous level of hs-TnI was checked thrice. Patients aged below 20 years with no risk factors for atherosclerosis were evaluated by stress echocardiography, and the rest underwent coronary angiography. Results: The mean age of the study population was 41.51 ± 17.82 years. ECG was normal in 48% of the patients, despite elevated levels of hs-TnI. Extensive myocardial infarction was reported in 3% of the study population, and 49% showed ST-T changes. The mean QT-interval was 422.50  77.35 ms in women and 434.28  67.28 in men (P = 0.578). Patients with torsades de pointes had a QT-interval of greater than 500 ms. The mean left ventricular ejection fraction was 55.41  9.85%. All the stress echocardiographic examinations were normal. Twenty-four patients had stenosis exceeding 50% in coronary angiography. The entire study population was older than 40 years of age with more than 1 coronary artery risk factor. Conclusions: Methadone elevated hs-TnI with and without ST-T changes. Most of our patients had normal coronary arteries in angiography and stress echocardiography. Indeed, even the patients with ST elevation in the anterior leads, combined with a reduced ejection fraction, were ultimately diagnosed as Takotsubo cardiomyopathy. We conclude that elevated hs-TnI in methadone toxicity should not be considered non–ST-segment elevation myocardial infarction.