Clinical Research Directory

Inclusion Criteria: * Patients undergoing elective non-cardiac surgery defined as intermediate or high-risk by the 2022 european society of cardiology (ESC) guidelines * expected duration of surgery of at least 90 minutes; * expected length of hospital stay ≥ 24 hours; * age \> 45 years with at least two of the following risk factors (adapted from revised cardiac risk index): * ischemic heart disease (history of myocardial infarction or positive exercise test, current complaint of chest pain considered to be secondary to myocardial ischemia, use of nitrates, pathological Q waves, prior coronary revascularization); * history of congestive heart failure; * history of cerebrovascular disease; * insulin-dependent diabetes mellitus; * creatinine \> 176.8 mmol/l; * pre-operative NTproBNP \> 200 pg/ml; * excessive sympathetic outflow as proven by exercise testing: * impaired HR recovery (≤ 12 bpm within 1 minute after cessation of exercise); OR * exaggerated HR response (≥ 12 bpm after 1 minute of unloaded pedalling); Exclusion Criteria: * unable to consent or follow study procedures; * absolute contraindications for exercise testing; * pregnancy or intention to become pregnant; * active cardiac conditions (such as unstable coronary syndromes, decompensated heart failure, significant arrhythmias, severe valvular disease); * urgent / emergency surgery; * already on β-blocker (within the last 30 days prior to recruitment); * contraindication for β-blocker therapy (bradycardia (HR \< 55 bpm), hypotension (systolic blood pressure \< 100 mmHg), severe peripheral vascular disease, severe asthma, allergy, higher-degree atrioventricular block); * severe preoperative anaemia (haemoglobin \< 100 g/L) unless there is a plan set up and followed for correction prior to surgery; * planned intermediate care or intensive care admission; * prior enrolment in this trial.