Life Science Journal 2012;9(4) http://www.lifesciencesite.com http://www.lifesciencesite.com lifesciencej@gmail.com 3126 A Double-Blind, Randomized Clinical Trial Comparing Cardioprotective Effects of N-acetylcysteine and Glucose-Insulin-Potassium as an Additive to Cardioplegia during Coronary Artery Bypass Grafting Mohammad Reza Habibi 1 , Shervin Ziabakhsh-Tabari 2 , Alireza Khalilian 3 , Samira Rahemi 4 , Rozita Jalalian 5 1. Department of Anesthesiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 2. Department of Cardiac Surgery, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 3. Department of Biostatistics, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 4. Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 5. Department of Cardiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Corresponding author: Dr. Mohammad Reza Habibi Mazandaran Heart Center, Artesh Boulevard, Mazandaran Province, Sari, Iran. Email: contactroute@yahoo.com Abstract: Optimum conditions for many coronary artery bypass graft surgeries (CABG) necessitate the heart to be prevented from beating. Cardioplegic solution and its ingredients are thus of utmost importance in cardioprotection. An ideal protection will help the heart return into its normal function after CABG. This research compared the cardioprotective effects of adding either N-acetylcysteine (NAC) to Cardioplegic solution with infusion of glucose- insulin-potassium (GIK) in patients with low ejection fraction (EF). In a double-blind randomized clinical trial, 60 elective CABG patients with EF < 50% were evaluated. The patients were numbered according to their reference to the Heart Center of Mazandaran (Iran) and their arrangements in the operation list. They were randomly allocated to 2 groups of 30 by a computer program to receive either GIK (group G) or NAC (group N). Compared to group G, group N had significantly lower incidence of arrhythmia during and after the operation (p = 0.041). They also needed lower doses of inotropic medications after the termination of cardiopulmonary bypass (CPB) (p = 0.041). The 2 groups were not significantly different in the need for shock or pacemaker after CPB and using pacemakers and inotropic drugs in the intensive care unit. Changes in mean EF from before to after the operation were 0.87 ± 0.85% in group N and -2.24 ± 1.02% in group G (p = 0.012). The mean troponin I levels were 0.406±0.316, 0.41 ± 0.512 in groups N and G, respectively (p = 0.41). NAC seems to be more beneficial than GIK for protecting myocardial cells, decreasing threatening signs of patients, especially arrhythmia, and increasing EF after CABG. It would probably decrease the mortality risk associated with arrhythmias. [ Mohammad Reza Habibi, Shervin Ziabakhsh-Tabari, Alireza Khalilian, Samira Rahemi, Rozita Jalalian. A Double-Blind, Randomized Clinical Trial Comparing Cardioprotective Effects of N-acetylcysteine and Glucose-Insulin-Potassium as an Additive to Cardioplegia during Coronary Artery Bypass Grafting. Life Sci J 2012;9(4):3126-3130] (ISSN:1097-8135). http://www.lifesciencesite.com . 457 Keywords: Coronary Artery Bypass Graft, N-acetylcysteine, Cardioplegia. Glucose-insulin-potassium (GIK) 1. Introduction Optimum conditions for many coronary artery bypass graft surgeries (CABG) necessitate the heart to be prevented from beating. On the other hand, the heart would not survive without an appropriate blood circulation. Since cardiac ischemia and reperfusion can produce free radicals and thus damage cardiac myositis and coronary artery endothelial cells, cardioplegia should be performed according to scientific and guaranteed principles to prevent ischemic incidences and irreversible complications (1,2). In addition, overproduction of free radicals causes macromolecular injuries, lipid peroxidation, and tissue deterioration (3) as a result of changes in cell membrane permeability and arrangement of membrane proteins following reperfusion and ischemic injury. Therefore, the composition of cardioplegic solution plays a vital role in protecting the heart. In fact, using an ideal protection, the heart will return to its normal function after the termination of cardiopulmonary bypass. Previous studies have employed different kinds of cardioplegic solutions such as crystalloid, blood, and L-arginine cardioplegic solutions (4,5). Research has also shown that adding factors to inhibit oxygen free radicals to the primary solution of cardiopulmonary bypass pump or to the cardioplegic solution can improve the heart function (6). On the other hand, patients with an ejection fraction (EF) lower than normal need to benefit from precise and specific medical supports or else their heart will not be able to function properly despite the conducted surgical procedures. In such cases, supportive measures are taken before, during, and after the surgery to decrease the complications of myocardial ischemia. Among these measures is using glucose-insulin-potassium (GIK) before operation and cold blood cardioplegia during the surgery. Being a branched-chain, low