Antiarrhythmic effect of ischemic preconditioning in recent unstable angina patients undergoing coronary artery...

Coronary artery bypass grafting (CABG) for unstable angina pectoris patients results in a higher incidence of arrhythmia and higher arrhythmic cardiac mortality. Ischemic preconditioning (IP) has proved effective in suppressing ischemia reperfusion arrhythmias in animals and in humans. The purpose of the present study was to investigate whether IP protects against postoperative arrhythmias in recent unstable angina patients undergoing urgent CABG. Forty-one patients with recent unstable angina and three-vessel coronary artery disease admitted for CABG were randomized into an IP group and a control group. The IP protocol involved twice occluding the ascending aorta with a cross-clamp for 2 minutes, followed by 3 minutes of reperfusion. Twenty-four-hour continuous electrocardiography (24-h ECG) was recorded from the preoperative day to the 2nd postoperative day. The incidences of supraventricular extrasystole (SVES), ventricular extrasystole (VES), supraventricular tachycardia (SVT), and ventricular tachycardia (VT) were 95.2%, 85.7%, 26.2%, and 26.2%, respectively, before surgery and 100.0%, 100.0%, 88.1%, and 76.2%, respectively, after surgery. IP significantly reduced the incidence of VT and the severity of SVES, VES, SVT, and VT after surgery. The period of mechanical ventilation and the length of stay in the intensive care unit were significantly shorter in the IP group. In summary, rhythm disturbances are common in CABG patients with recent unstable angina. IP significantly reduces rhythm disturbances, including SVES, VES, SVT, and VT after CABG. The findings indicate that IP could constitute an additional myocardial protective strategy in recently unstable angina patients undergoing CABG.