Study design Each patient will be assessed with history and physical examination, 12-lead ECG, serum troponin, coronary arteriography, and LV angiogram (an average of 6 hours after admission to the hospital), with echocardiography and 123Imetaiodobenzylguanidine (MIBG) myocardial scintillography. All patients were admitted to the cardiac care unit after coronary angiography. Currently recommended treatments for acute coronary syndromes (ACS), with therapy directed at relieving myocardial ischemia and preventing thrombotic complications, were provided to all patients. For each patient, the Charlson score index, 8 which represents the most studied and evaluated comorbidity index, will be calculated. At discharge, surviving patients with established SC will be managed and followed for 12 month after the event, as outpatients. At discharge, the surviving patients will be randomly assigned to alpha-lipoic acid 800 mg/day treatment (ALA group), or L-acetyl carnitine 1000 mg/day treatment (LAC group) or placebo (control group). With regard to the full medical therapy, the protocol stated that the use of concomitant treatment should be uniform, between the groups, and according to evidence-based international guidelines for ACS in all patients. Following discharge, patients were asked to return to our outpatient clinic for follow-up evaluation at 6 and 12 months after the initial event of SC.

Coronary Angiography Coronary angiograms at baseline, immediately after percutaneous coronary intervention (PCI) will be performed in at least 2 orthogonal views after intracoronary nitroglycerin. The analyses of all angiographic data will be performed by operators who were unaware of the study groups (Toshiba, Infinix CS-i).

Echocardiography LV function will be evaluated in all patients by two-dimensional echocardiography at admission, 6 and 12 months after the discharge.

MIBG imaging. MIBG imaging will be performed in all patients shortly after admission and at 6 and 12 months after the discharge. MIBG will be performed with a The standard protocol for 123I-MIBG cardiac imaging requires that drugs that interfere with 123I-MIBG uptake be withheld. A comprehensive listing of prescription and over-the-counter drugs that interfere with 123I-MIBG biodistribution, and the time for which they should be withheld, has been published . Thyroid uptake of unbound 123I is blocked with 500 mg of potassium perchlorate given orally 30 min before 123I-MIBG injection. Between 148 MBq and 370 MBq of 123I-MIBG are injected intravenously at rest. Both planar and SPECT images are acquired 15 min after injection (early) and 4 h after injection (delayed). A dual head gammacamera (ECAM Siemens, Erlangen - Germany) equipped with a low-energy - high resolution collimator was used. A 20% window is usually centered over the 159-keV photopeak of 123I for imaging. Anterior planar images of the chest are acquired using a 256 x 256 matrix. single photon emission computed tomography (SPECT) images are acquired using a 64 x 64 matrix over 180°, from the right anterior oblique position to the left posterior oblique position. Planar imaging allows for global assessment of cardiac innervation, whereas SPECT allows for regional evaluation. Quantitative evaluations will be performed with a standard protocol previously described.