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

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.  

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.  

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.  

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. (Iranian Heart Journal 2020; 21(3): 128-136)