The recommendations by the (AHA) American Heart Association and the (ACC) American Colleague of Cardiology attempt to identify low and high risk cardiac patients by preoperative clinical and non-invasive evaluation aiming to choose the optimum cardiac risk reduction strategy were presented. Clinical evidence demonstrated a cardio protective effect of perioperative β-adrenergic receptor blockers use in non-cardiac surgery. In the current study done on high risk cardiac patients undergoing major vascular surgery, we proved that the use of Atenolol (Immediate use) and maintaining it orally postoperatively throughout the hospitalization period will be as effective as early administration of oral Atenolol in preventing major cardiovascular effect, but in the same time will decrease the number of cancelled procedures and total hospital length of stay.