Recently, dexmedetomidine has been suggested as an alternative agent for sedation in tachyarrhythmias due to its antiarrhythmic properties through decreased catecholamine release, prolonged refractory period, and increased vagal tone. In addition, dexmedetomidine is a highly selective agonist that does not interact with the gamma-aminobutyric acid (GABA) receptors. Thus, its analgesic properties are opioid sparing, which is unique among traditional ICU sedatives and avoids the issue of respiratory depression with over-sedation.

Our aim: To evaluate the potential prophylactic effect of perioperative dexmedetomidine in reducing the incidence of early postoperative new onset atrial fibrillation following mitral valve surgery.

Inclusion Criteria:

Adult patients aged 21 years or older. American Society of Anesthesiologists (ASA) physical status II-III. Patients able to provide written informed consent.

Exclusion Criteria:

History of cardiac arrhythmias: atrial fibrillation or any other clinically significant cardiac tachyarrhythmias.

Any degree of atrioventricular block or presence of permanent pacemaker and bradycardia (heart rate < 60 beats/min) or hemodynamic instability.

Emergency mitral valve surgery. Left ventricular dysfunction (ejection fraction < 55%) Ischemic heart disease patients. Severe hepatic or renal impairment. Known hypersensitivity or contraindication to dexmedetomidine. Chronic use of class I or class III anti-arrhythmic drugs