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

NCT07002450 | Recruiting DMC

• 1 other identifier: 20240752-01T
• Study Type: interventional
• Target: 190
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Atrial Fibrillation (AF); Atrial Flutter

Keywords

Cardiac computed tomography angiography; Cardioversion; Atrial flutter; Atrial fibrillation

Outcome Measures

Primary Outcomes (1)

• Primary composite outcome

  Using a hierarchical win ratio: 1. All-cause death 2. Stroke, transient ischemic attack, or systemic embolism 3. Admission to hospital for a cardiac or AF related reason 4. Repeat presentation to hospital for a cardiac or AF related reason 5. Improvement in AF Effect On Quality-Of-Life Questionnaire (AFEQT) quality of life greater than or equal to 5 points

  Randomization to 30 days

Secondary Outcomes (12)

• Composite objective outcomes

  Randomization to 30 days

• All-cause death

  Randomization to 30 days

• Cardiovascular death

  Randomization to 30 days

• Stroke, transient ischemic attack, or systemic embolism

  Randomization to 30 days

• Hospital admission for a cardiac or AF related reason

  Randomization to 30 days

Other Outcomes (1)

• Cost effectiveness

  Emergency department presentation to 30 days

Study Arms (2)

Standard of Care

ACTIVE COMPARATOR

Patients in the control arm will be treated according to current standard of care as determined by the primary treating emergency department physician and may vary by institution and physician. Treatment in the standard of care group may include a rate control strategy with or without a planned cardioversion after 3 weeks of anticoagulation, deferring management for outpatient evaluation, request for TEE-facilitated cardioversion in the ED, or specialist consultation for further management or admission to hospital.

Other: Standard of care management

CCT-facilitated cardioversion arm

EXPERIMENTAL

Patients in this arm will undergo cardiac computed tomography angiography (CCT) to evaluate for a left atrial/left atrial appendage (LA) thrombus. If the CCT shows no LA thrombus then the emergency department physician will be able to perform electrical and/or chemical cardioversion at their discretion. If the CCT shows a LA thrombus then cardioversion will be contraindicated and further management will be at the discretion of the treating physician.

Diagnostic Test: Cardiac computed tomography angiography

Interventions

Standard of care management OTHER

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.

Standard of Care

Cardiac computed tomography angiography DIAGNOSTIC_TEST

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.

CCT-facilitated cardioversion arm

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥18 years old; and
• Primary symptomatic AF without a reversible underlying cause (e.g. sepsis, pneumonia, pulmonary embolism, hyperthyroidism)
• LA imaging required before cardioversion according to local clinical practice guidelines

You may not qualify if:

• Patients with an indication for emergency cardioversion (e.g. hemodynamic instability (systolic blood pressure\<90mmHg or signs of shock), cardiac ischemia (ongoing severe chest pain or marked ST depression on ECG \>2mm), or pulmonary edema (significant dyspnea, crackles, or hypoxia)); or
• Contraindication to CCT (renal insufficiency (eGFR\< 45ml/min/1.73m2), allergy to intravenous contrast agents, pregnancy (contraindications to radiation exposure), or inability to perform 20-second breath-hold)

Sponsors & Collaborators

• Ottawa Heart Institute Research Corporation: lead

Study Sites (1)

The Ottawa Hospital Civic Campus

Ottawa, Ontario, K1Y 1J8, Canada

RECRUITING

MeSH Terms

Conditions

Atrial Fibrillation; Atrial Flutter

Condition Hierarchy (Ancestors)

Arrhythmias, Cardiac; Heart Diseases; Cardiovascular Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Benjamin Chow, MD PhD FRCPC FACC FESC FA

  Ottawa Heart Institute Research Corporation

  PRINCIPAL INVESTIGATOR

• Mehrdad Golian, MD MSC FRCPC

  Ottawa Heart Institute Research Corporation

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Farrah Ahmed

CONTACT

613-696-7000; fahmed@ottawaheart.ca

Yeung Yam

CONTACT

613-696-7000; yyam@ottawaheart.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: INVESTIGATOR
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 8, 2025
• First Posted: June 3, 2025
• Study Start: June 15, 2025
• Primary Completion (Estimated): June 15, 2028
• Study Completion (Estimated): June 15, 2028
• Last Updated: April 17, 2026

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: Study completion
• Access Criteria: The above will be made publicly available.

Locations

CA (1)