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

University of Ottawa Heart Institute

Status: Completed

Conditions: Atrial Fibrillation

Treatments: Diagnostic Test: Transesophageal Echocardiography (TEE); Diagnostic Test: Contrast enhanced ECG-gated cardiac CT (CCT)

Study type: Interventional

Funder types: Other

Identifiers

NCT04223505

201900117-01H

Details and patient eligibility

About

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.

Enrollment: 102 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Diagnostic

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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102 participants in 2 patient groups

TEE arm

Active Comparator group

Description:

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.

Treatment:

Diagnostic Test: Transesophageal Echocardiography (TEE)

CCT arm

Experimental group

Description:

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.

Treatment:

Diagnostic Test: Contrast enhanced ECG-gated cardiac CT (CCT)

Diagnostic Test: Transesophageal Echocardiography (TEE)