Electrical cardioversion (ECV) is a standard procedure used to restore normal heart rhythm in patients with atrial fibrillation (AF) by delivering a brief electrical shock to the heart. Because the procedure is painful and distressing, patients receive sedation - a controlled state of reduced consciousness - using short-acting intravenous medications. However, the optimal depth of sedation for ECV has not been well defined: too deep may cause breathing problems and low blood pressure, while too light may result in pain, awareness, or patient movement during the shock.
Bispectral index (BIS) monitoring is a non-invasive technology that continuously measures brain activity using an EEG sensor placed on the forehead, generating a numerical score from 0 (no brain activity) to 100 (fully awake). BIS scores between 61 and 80 correspond to moderate sedation, which preliminary observations suggest may be sufficient for ECV without the risks associated with deeper sedation.
This randomized controlled trial will compare two approaches to sedation monitoring during elective ECV for AF:
* Group 1 (BIS Group): Sedation is guided by BIS monitoring, targeting a score of 61-80. * Group 2 (Control Group): Sedation is guided by standard clinical assessment (loss of response to verbal commands and eyelash reflex), with BIS recorded but not visible to the treating team.
Both groups will receive the same medications (propofol and fentanyl). The primary outcome is how quickly patients recover after the procedure, measured by the Modified Aldrete Score - a standard clinical recovery assessment tool. Secondary outcomes include patient and physician satisfaction, procedural pain, risk of awareness during the procedure, cardioversion success rate, hemodynamic stability, and complication rates.
The trial will enroll 60 adult patients at Istanbul University-Cerrahpasa Cardiology Institute. Findings are expected to provide evidence-based guidance for standardizing sedation protocols during ECV.
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
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
Parallel
BIS-guided propofol sedation
DrugIV propofol 0.5-1 mg/kg titrated to BIS 61-80, preceded by IV fentanyl 0.5-1 µg/kg. Additional propofol 0.25-0.5 mg/kg boluses as needed for repeat shocks within target range.
Clinical-guided propofol sedation
DrugIV propofol 0.5-1 mg/kg titrated to clinical endpoints, preceded by IV fentanyl 0.5-1 µg/kg. BIS recording passive (blinded to operator).
Time to Recovery (Modified Aldrete Score ≥9)
Time in minutes from sedation induction (first propofol dose) to achievement of Modified Aldrete Score ≥9, assessed by an independent, blinded anesthesiologist. The Modified Aldrete Score evaluates activity, respiration, circulation, consciousness, and oxygen saturation (0-2 points each; maximum 10). Score ≥9 indicates readiness for discharge from monitored care.
Patient Satisfaction
Patient-reported global satisfaction with the procedure assessed using a 5-point Likert scale (1 = very dissatisfied to 5 = very satisfied), administered by the blinded assessor after Modified Aldrete Score ≥9 is achieved.
Physician Satisfaction
Treating cardiologist's global satisfaction with sedation conditions assessed using a 5-point Likert scale (1 = very dissatisfied to 5 = very satisfied), recorded immediately after the procedure.
Procedural Pain
Patient-reported pain intensity during the procedure assessed using the Numeric Rating Scale-11 (NRS-11; 0 = no pain, 10 = worst imaginable pain), administered after recovery.
Cardioversion Success Rate
Proportion of patients achieving restoration of sinus rhythm confirmed by 12-lead ECG within 1 hour of the procedure.
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