Atrial FibrillationLACLOTNCT04223505
Left Atrial Imaging Prior to Cardioversion: Leveraging Computed Tomography to Rule Out Thrombus
A study testing Contrast enhanced ECG-gated cardiac CT (CCT) and Transesophageal Echocardiography (TEE) in people with Atrial Fibrillation, run by Ottawa Heart Institute Research Corporation at 1 site in Canada.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Atrial Fibrillation
- What is being tested?
- Contrast enhanced ECG-gated cardiac CT (CCT) and Transesophageal Echocardiography (TEE)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 102 participants
- Where
- 1 siteCanada
- Study dates
- 26 Jun 2020to 12 Jan 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Admitted patients who require LA imaging prior to cardioversion
- Age ≥18 years old
- Able and willing to comply with the study procedures
Who cannot join
- Indication for acute cardioversion (e.g. hemodynamic instability, acute coronary syndrome (ACS), or pulmonary edema)
- Unwillingness or inability to provide informed consent
- Contraindication to Cardiac CT
- Severe renal insufficiency(GFR< 45ml/min)
- Allergy to intravenous contrast agents
- Contraindications to radiation exposure (for example, pregnancy)
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- Inability to perform 20-second breath-hold
- Contraindication to TEE
- Unrepaired tracheoesophageal fistula
- Esophageal obstruction or stricture
- Perforated hollow viscus
- Poor airway control
- Severe respiratory depression
- Uncooperative, unsedated patient
Trial locations and contacts
1 site in 1 country.
About this study
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.
- Conditions
- Atrial Fibrillation
- Being tested
- Contrast enhanced ECG-gated cardiac CT (CCT), Transesophageal Echocardiography (TEE)
- Medical subject headings
- Atrial Fibrillation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Contrast enhanced ECG-gated cardiac CT (CCT)Diagnostic test
Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude of left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated. CCT, compared to TEE, for the exclusion of thrombus in the LAA had a sensitivity and specificity of 100% and 99.3%, respectively. A high sensitivity is needed to minimize risk of embolus, and if a thrombus is detected on CT, a confirmatory TEE may be performed or patients may receive anticoagulation. Some argue that the potential benefits of CT and its lower associated procedural risk, the risk:benefit ratio would still favour CT.
Transesophageal Echocardiography (TEE)Diagnostic test
TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.
| Study group | Role | What they receive |
|---|---|---|
| TEE arm | Active comparator | 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. Receives: Diagnostic Test: Transesophageal Echocardiography (TEE) |
| CCT arm | Experimental | 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. Receives: Diagnostic Test: Contrast enhanced ECG-gated cardiac CT (CCT); Diagnostic Test: Transesophageal Echocardiography (TEE) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to Imaging
This outcome was measured by calculating the time between admission and imaging.
Measured: From admission to imaging/spontaneous cardioversion, up to approximately 30 days.
Secondary outcomes (1)
Time to Cardioversion
This outcome was measured by calculating the time between admission and cardioversion.
Measured: From admission to cardioversion, up to approximately 30 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jan 2020
- Study start26 Jun 2020
- Primary completion21 Nov 2023
- Study completion12 Jan 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Atrial FibrillationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 102 participants (actual)
Sponsor and investigators
- Lead sponsor
- Ottawa Heart Institute Research Corporation
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Benjamin Chow, MD, Principal investigator, UOHI
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04223505
- Sponsor's protocol ID
- 201900117-01H
- Acronym
- LACLOT
- Status last verified
- Sep 2024
- First submitted
- 6 Jan 2020
- Last updated
- 12 Mar 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Left Atrial Imaging Prior to Cardioversion: Leveraging Computed Tomography to Rule Out Thrombus
- ClinicalTrials.gov ID
- NCT04223505
- Acronym / sponsor ID
- LACLOT / 201900117-01H
- Conditions
- Atrial Fibrillation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 102 participants (actual)
- Lead sponsor
- Ottawa Heart Institute Research CorporationUniversity, hospital or other
- Study start
- 26 Jun 2020 (actual)
- Primary completion
- 21 Nov 2023 (actual)
- Study completion
- 12 Jan 2024 (actual)
- First posted
- 10 Jan 2020 (actual)
- Results
- Posted 12 Mar 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| TEE arm | Active comparator | Diagnostic Test: 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 | Experimental | Diagnostic Test: Contrast enhanced ECG-gated cardiac CT (CCT), Diagnostic Test: 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Admitted patients who require LA imaging prior to cardioversion
- Age ≥18 years old
- Able and willing to comply with the study procedures
Key exclusion criteria (14 listed)
- Indication for acute cardioversion (e.g. hemodynamic instability, acute coronary syndrome (ACS), or pulmonary edema)
- Unwillingness or inability to provide informed consent
- Contraindication to Cardiac CT
- Contraindication to TEE
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Contrast enhanced ECG-gated cardiac CT (CCT)Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude of left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated. CCT, compared to TEE, for the exclusion of thrombus in the LAA had a sensitivity and specificity of 100% and 99.3%, respectively. A high sensitivity is needed to minimize risk of embolus, and if a thrombus is detected on CT, a confirmatory TEE may be performed or patients may receive anticoagulation. Some argue that the potential benefits of CT and its lower associated procedural risk, the risk:benefit ratio would still favour CT. | Diagnostic test | CCT arm |
| Transesophageal Echocardiography (TEE)TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%. | Diagnostic test | CCT arm, TEE arm |
Primary outcome
Time to Imaging
Time frame: From admission to imaging/spontaneous cardioversion, up to approximately 30 days.
This outcome was measured by calculating the time between admission and imaging.
1 secondary outcome
Time to Cardioversion
Time frame: From admission to cardioversion, up to approximately 30 days
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Mar 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Benjamin Chow, MD principal investigator
UOHI
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Contrast enhanced ECG-gated cardiac CT (CCT) and Transesophageal Echocardiography (TEE) in people with Atrial Fibrillation, run by Ottawa Heart Institute Research Corporation at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 12 Mar 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to Imaging (time frame: From admission to imaging/spontaneous cardioversion, up to approximately 30 days.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Mar 2025.