BIS-Guided Sedation Versus Standard Clinical Sedation During Elective Electrical Cardioversion for Atrial Fibrillation (BIS-ECV-RCT)

Bispectral Index-Guided Sedation Versus Standard Clinical Assessment-Guided Sedation During Elective Electrical Cardioversion for Atrial Fibrillation: A Prospective, Single-Center, Randomized Controlled, Assessor-Blinded Trial

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.

Study Overview

• Status: Recruiting
• Conditions: Atrial Fibrillation; Deep Sedation; Electric Countershock
• Intervention / Treatment: Drug: BIS-guided propofol sedation; Drug: Clinical-guided propofol sedation

Detailed Description

Background:

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia. Elective electrical cardioversion (ECV) is a widely used rhythm control strategy. Procedural sedation is a critical component of ECV; however, the optimal monitoring method and depth of sedation remain undefined. Excessive sedation risks respiratory depression and hemodynamic instability, particularly in patients with structural heart disease, while inadequate sedation may result in patient movement, pain, and procedural awareness.

Bispectral index (BIS) monitoring offers objective, real-time quantification of sedation depth. Preliminary clinical observation at our center suggests that BIS 61-80 provides adequate procedural conditions for ECV with propofol-fentanyl sedation, while deeper sedation (BIS <60) is associated with increased respiratory depression without additional procedural benefit.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: AYLA ESIN; Phone Number: +905326343959; Email: ayla.esin@iuc.edu.tr

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Recruiting
    • Istanbul University-Cerrahpasa, Cardiology Institute
    • Contact: AYLA ESIN, MD; Phone Number: 00905326343959; Email: ayla.esin@iuc.edu.tr
    • Principal Investigator: Kerem Erkalp, Professor MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: BIS-Guided Sedation (BIS Group); Patients in this group receive sedation with intravenous fentanyl (0.5-1 µg/kg) followed by titrated propofol (0.5-1 mg/kg) guided by continuous BIS monitoring, targeting a BIS range of 61-80. Cardioversion is initiated once the target BIS range is achieved and clinical endpoints (loss of verbal contact, loss of eyelash reflex) are confirmed.	Drug: BIS-guided propofol sedation; IV 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.
Active Comparator: Standard Clinical Sedation (Control Group); Patients in this group receive sedation with intravenous fentanyl (0.5-1 µg/kg) followed by titrated propofol (0.5-1 mg/kg) guided by standard clinical assessment (loss of verbal contact, loss of eyelash reflex). BIS monitoring is applied but the monitor screen is physically concealed from the treating team. BIS values are recorded for analysis only.	Drug: Clinical-guided propofol sedation; IV 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).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	From sedation induction to Modified Aldrete Score ≥9, assessed every 5 minutes post-ECV for up to 60 minutes.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Within 60 minutes post-procedure.
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.	Immediately post-procedure (within 5 minutes of ECV completion).
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.	Within 60 minutes post-procedure (after Modified Aldrete Score ≥9).
Cardioversion Success Rate	Proportion of patients achieving restoration of sinus rhythm confirmed by 12-lead ECG within 1 hour of the procedure.	Within 1 hour post-ECV.
Incidence of sedation related complications	Proportion of patients experiencing any of the following: hypotension (systolic BP <90 mmHg), bradycardia (HR <50 bpm), oxygen desaturation (SpO₂ <90%), apnea, laryngospasm, or procedurally significant arrhythmia. Recorded as a composite binary outcome (yes/no).	From sedation induction to 60 minutes post-procedure.
Number of Cardioversion Shocks and Total Energy Delivered	Total number of synchronized shocks delivered and cumulative energy (Joules) used per patient.	During the ECV procedure.
Total Anesthetic Drug Consumption	Total dose (mg/kg) of propofol and fentanyl (µg/kg) administered during the procedure.	During procedure

Collaborators and Investigators

• Sponsor: Istanbul University - Cerrahpasa
• Investigators: Principal Investigator: Kerem Erkalp, Professor Dr, Istanbul University - Cerrahpasa

Study record dates

Study Major Dates

• Study Start (Actual): April 13, 2026
• Primary Completion (Estimated): June 15, 2026
• Study Completion (Estimated): July 15, 2026

Study Registration Dates

• First Submitted: April 12, 2026
• First Submitted That Met QC Criteria: May 1, 2026
• First Posted (Actual): May 6, 2026

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: atrial fibrillation; sedation; propofol; bispectral index; anesthesia recovery; Electric Countershock
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: 20260404

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared publicly. Aggregate de-identified results will be reported in peer-reviewed publications.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No