NCT07002450

Left Atrial Imaging Prior to Cardioversion: Leveraging Computed Tomography to Rule Out Thrombus in The Emergency Department (LA CLOTTED)

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 190 (estimated)
• Sponsor: Ottawa Heart Institute Research Corporation · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The goal of this randomized clinical trial is to learn whether patients with symptomatic atrial fibrillation or atrial flutter (AF) who require heart imaging to rule out a blood clot before cardioversion would benefit from cardiac computed tomography angiography (CCT) in the emergency department (ED) compared to current standard of care management. This will be a multicenter trial evaluating whether CCT-facilitated cardioversion in the ED reduces hospital admission, reduces repeat presentations to hospital and improves patient quality of life compared to the current standard of care. Participants will undergo CCT-facilitated cardioversion or be treated according to current standard of care while in the ED and complete quality of life questionnaires in the ED and follow-up at 30 days.

Detailed description

Atrial fibrillation and atrial flutter (AF) are the most common cardiac arrhythmias worldwide resulting in frequent visits to the emergency department (ED). Some patients can undergo chemical or electrical cardioversion to restore their heart back to a sinus rhythm. However, if a patient is not on blood thinners and the duration of AF is prolonged then blood clots may form in the heart increasing the risk of stroke after cardioversion. Therefore, some patients must undergo heart imaging to rule out any blood clots before cardioversion is considered safe. Transesophageal echocardiography (TEE) is commonly used to rule out blood clots, but it is not readily available in all EDs often resulting in hospital admission to facilitate this test or deferring cardioversion until 3 weeks of blood thinners have been completed. Cardiac computed tomography angiography (CCT) is a more readily available alternative to TEE that can be done rapidly in the ED. CCT has excellent sensitivity and specificity compared to TEE for identifying cardiac thrombus. If there is no thrombus detected on the CCT then patients could be immediately cardioverted to sinus rhythm thus avoiding an unnecessary hospital admission and reducing the symptom burden associated with remaining in AF. This study is a multicenter randomized trial that will evaluate the effectiveness of using CCT facilitated cardioversion in the ED compared to current standard of care management.

Conditions

• Atrial Fibrillation (AF)
• Atrial Flutter

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	Cardiac computed tomography angiography	Patients will undergo CCT according to the following protocol. A non-contrast enhanced prospective ECG-triggered image will be acquired followed by a contrast-enhanced prospective ECG-triggered image using a tri-phasic contrast protocol. Delayed CT images 60 seconds after the initial contrast-enhanced CT scan will be obtained. Cardiac CT image interpretation will be performed according to routine clinical practices in a pragmatic fashion. The LA will be assessed for filling defects and characterized based upon attenuation values. If LA 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. If the CCT shows no LA thrombus then the ED physician will be able to perform electrical and/or chemical cardioversion at their discretion.
OTHER	Standard of care management	Patients in the standard of care arm may undergo any combination of the following management strategies in the emergency department (ED) at the discretion of their treating physician: 1\. Transesophageal echocardiogram (TEE) facilitated cardioversion; 2. Rate control; 3. Consultation with inpatient cardiac specialist for assessment/management and consideration of hospital admission; 4. cardioversion after 3 weeks of anticoagulation; and/or 5. Outpatient referral to cardiac specialist or general practitioner for further management.

Timeline

• Start date: 2025-06-15
• Primary completion: 2028-06-15
• Completion: 2028-06-15
• First posted: 2025-06-03
• Last updated: 2026-04-17

Locations

1 site across 1 country: Canada