Beta blockers for elective surgery in elderly patients: population based, retrospective cohort study.

The objective of the study was to test whether atenolol (a long acting beta blocker) and metoprolol (a short acting beta blocker) are associated with equivalent reductions in risk for older patients undergoing elective surgery. Myocardial infarction is a common complication after elective surgery and blockers are believed to reduce that risk. Sudden withdrawal of beta blockers may result in tachycardia, hypertension and cardiac ischaemia. The loss of the blockade around the time of surgery may predispose the patient to a myocardial infarction.