BIS-Guided Sedation Versus Standard Clinical Sedation During Elective Electrical Cardioversion for Atrial Fibrillation

Inclusion Criteria: * Age ≥18 years * Documented atrial fibrillation with indication for elective electrical cardioversion * American Society of Anesthesiologists (ASA) physical status class I, II, or III * Left ventricular ejection fraction ≥30% on echocardiography * Adequate anticoagulation: INR ≥2.0, OR ≥3 weeks of therapeutic anticoagulation, OR absence of left atrial thrombus confirmed by transesophageal echocardiography * Ability and willingness to provide written informed consent Exclusion Criteria: * Known allergy or contraindication to propofol or fentanyl, or their excipients (soy, egg) * Hemodynamic instability (systolic blood pressure \<90 mmHg or symptomatic hypotension) * Decompensated heart failure (NYHA functional class IV) * Severe obstructive sleep apnea requiring CPAP or BiPAP therapy * Anticipated difficult airway (modified Mallampati classification class III or IV) * Baseline oxygen saturation \<94% or active chronic obstructive pulmonary disease * Severe hepatic impairment (transaminases \>3× upper limit of normal) or severe renal impairment (eGFR \<30 mL/min/1.73m²) * Active psychiatric illness or cognitive impairment precluding questionnaire completion * Pregnancy or breastfeeding * Alcohol or substance use within the preceding 24 hours * Prior participation in this trial