Beta-blockers exert their cardioprotective effects by multiple mechanisms including: 1. Reduction in myocardial demand via reduction in heart rate and contractility, Improvement in energy efficiency and outcome, 3. Antiarrhythmic effect, 4. Anti-inflammatory effect, 5. Antirenin and antiangiotensin properties. The effects on heart rate, contractility and energy substrate shift from fatty acids to glucose occur quickly. The anti-inflammatory response become evident only after weeks of treatment.
There may be benefit to begin therapy 30 days before surgery to get all the pleiotropic effects. Dosage adjustments to gain a resting heart rate of 50 to 60 beats per minute are important. The drug therapy should not be interrupted during the perioperative period, in order to avoid rebound tachycardia and hypertension.
