Beta-blocker Before Extubation

Inclusion Criteria: * Adult medical or cardiac intensive care unit patients on mechanical ventilation who have known coronary artery disease or have at least 2 of the following risk factors for coronary artery disease: * Cigarette smoking * Hypertension (BP 140/90 or antihypertensive medication) * Low HDL-cholesterol (HDL-C) (\<40 mg/dL \[1.03 mmol/L\]) * Family history of premature CHD (in male first degree relatives \<55 years, in female first degree relative \<65 years) * Age (men 45 years, women 55 years) * Diabetes mellitus * Symptomatic carotid artery disease * Peripheral arterial disease * Abdominal aortic aneurysm Exclusion Criteria: * Arterial hypotension, defined as mean arterial pressure \< 60 mmHg or requiring any intravenous vasoactive medication. * The presence of known reactive airway disease. * Resting heart rate of \<60 in the period prior to tracheal extubation.. * The presence of decompensated congestive heart failure, defined as requiring continuous infusion of an inotropic agent. * Known hypersensitivity to beta-blockers or any other contraindication to their use. * Subjects younger than 18 years of age. * Inability to obtain consent from the subject or the subjects authorized representative. * Pregnancy * Digoxin therapy * Current therapy with a beta-blocker