Left Atrial Imaging Prior to Cardioversion: Leveraging Computed Tomography to Rule Out Thrombus

Not Applicable

Completed

• Conditions: Atrial Fibrillation
• Interventions: Diagnostic Test: Contrast enhanced ECG-gated cardiac CT (CCT); Diagnostic Test: Transesophageal Echocardiography (TEE)

• Registration Number: NCT04223505
• Lead Sponsor: Ottawa Heart Institute Research Corporation

Brief Summary

Evaluating contrast enhanced ECG-gated cardiac CT (CCT) as an alternative to transesophageal echocardiography (TEE) to expedite cardioversion of atrial fibrillation (AF), improve patient care and reduce hospital admissions for AF and atrial flutter.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2020-01-06
• Study First Submitted QC: 2020-01-08
• Study First Posted: 2020-01-10
• Study Start: 2020-06-26
• Primary Completion: 2023-11-21
• Study Completion: 2024-01-12
• Results First Submitted: 2024-04-16
• Status Verified: 2024-09
• Results First Submitted QC: 2025-02-20
• Last Update Submitted: 2025-02-20
• Results First Posted: 2025-03-12
• Last Update Posted: 2025-03-12

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 102

Inclusion Criteria

1. Admitted patients who require LA imaging prior to cardioversion
2. Age ≥18 years old
3. Able and willing to comply with the study procedures

Exclusion Criteria

1. Indication for acute cardioversion (e.g. hemodynamic instability, acute coronary syndrome (ACS), or pulmonary edema)

2. Unwillingness or inability to provide informed consent

3. Contraindication to Cardiac CT

   • Severe renal insufficiency(GFR< 45ml/min)
   • Allergy to intravenous contrast agents
   • Contraindications to radiation exposure (for example, pregnancy)
   • Inability to perform 20-second breath-hold

4. Contraindication to TEE

   • Unrepaired tracheoesophageal fistula
   • Esophageal obstruction or stricture
   • Perforated hollow viscus
   • Poor airway control
   • Severe respiratory depression
   • Uncooperative, unsedated patient

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
CCT arm	Contrast enhanced ECG-gated cardiac CT (CCT)	As per local protocol, a non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using a tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after the initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE.
TEE arm	Transesophageal Echocardiography (TEE)	TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast.
CCT arm	Transesophageal Echocardiography (TEE)	As per local protocol, a non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using a tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after the initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE.

Primary Outcome Measures

Name	Time	Method
Time to Imaging	From admission to imaging/spontaneous cardioversion, up to approximately 30 days.	This outcome was measured by calculating the time between admission and imaging.

Secondary Outcome Measures

Name	Time	Method
Time to Cardioversion	From admission to cardioversion, up to approximately 30 days	This outcome was measured by calculating the time between admission and cardioversion.

Trial Locations

Locations (1)

University of Ottawa Heart Institute; 🇨🇦 Ottawa, Ontario, Canada