Landiolol for Prevention of Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery

Inclusion Criteria: 1. Male or female patients ≥ 18 years old 2. Written informed consent from patient 3. Patients are in sinus rhythm 4. Oral Betablocker in the patients long-term medication 5. One of the following cardiac surgical procedures which is planned on cardiopulmonary bypass (CPB): 1. Single valve surgery 2. Single or multiple CABG procedures 3. Single valve surgery in combination with one or multiple coronary artery bypass grafts (CABGs) 4. Multiple valve surgery in combination with or without CABG 5. Single or multiple valve surgery in combination with ascending aorta procedure with or without additional CABG 6. Re-surgery of aortic valve, mitral valve, aortic arch or ascending aorta with or without CABG 6. Cardiac surgery is performed electively Exclusion Criteria: 1. Bodyweight \> 101kg and/or BMI ≥ 40 2. Cardiac surgery is planned as minimally invasive procedure (e.g., without thoracotomy or with lateral incision, minimal thoracotomy) or planned as off-pump surgery 3. Planned maze procedure, radiofrequency ablation, pulmonary vein ablation, resection of the atrial appendix or atrial resections during the surgery 4. Sinus bradycardia (resting heart rate \< 50/min) at screening and before start of IMP treatment 5. Second- or third-degree atrioventricular block at screening and before start of IMP treatment 6. Clinical hypothyroidism or hyperthyroidism at screening 7. History of ventricular arrhythmia 8. Permanent atrial fibrillation or atrial fibrillation at time of screening and IMP administration 9. Emergency cardiac surgery 10. Requiring inotropic, vasopressor or requiring ventilatory support at time of screening 11. Circulatory shock requiring mechanical circulatory support before initiation of study medication 12. Distributive shock (cardiac index\>2.2 L/min with norepinephrine dose \> 0.3 µg/kg/min to reach mean arterial pressure \> 65mmHg) before initiation of study medication 13. More than 5 units of RBC necessary to maintain a haemoglobin level \>8mg/dl at the end of surgery 14. Prior cardiac surgery within the past 6 months 15. History of heart transplantation or planned heart transplantation 16. Any other disease or condition that is likely to interfere with the evaluation of the study drug, outcome assessment or satisfactory conduct of the study: 1. Active infective endocarditis 2. Stroke or transient ischemic attack (TIA) within the last 6 months 3. Concomitant disease with a life expectancy of less than 6 months 4. Cardiopulmonary resuscitation within the last 4 weeks 5. Patients requiring renal replacement therapy 17. Active infection on current systemic antibiotics and/ or temperature greater than 38°C at time of screening and before start of surgery 18. Haemoglobin \< 5 mmol/l (\< 8.06 g/dl) 19. Any systemic anti-cancer therapy within past 3 months 20. Patients with known hypersensitivity to any constituent of the IMP 21. General exclusion criteria: 1. Pregnant (in women of childbearing potential a urine or blood pregnancy test has to be performed) or breast-feeding women. Women with childbearing potential (defined as within two years of their last menstruation) not willing to practice appropriate contraceptive measures (e.g., implanon, injections, oral contraceptives, intrauterine devices, partner with vasectomy, abstinence) while participating in the trial 2. Participation in any interventional clinical trial within the last one-month prior randomization in this clinicaltrial (screening failures can be rescreened, if appropriate) 3. Alcohol, drug, or medication abuse 4. Employee at the study site, spouse/partner or relative of any study staff (e.g., investigator, subinvestigators, or study nurse) or relationship to the sponsor