Cardiac Imaging Before Cardioversion for Atrial Fibrillation

(LACLOT Trial)

Overseen By Sandina Jamieson

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Ottawa Heart Institute Research Corporation

Disqualifiers: Severe renal insufficiency, Pregnancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new method to prepare individuals with atrial fibrillation (AF) for cardioversion, a procedure that resets the heart's rhythm. Researchers are testing whether a contrast-enhanced ECG-gated cardiac CT (CCT) can replace the usual transesophageal echocardiography (TEE) to expedite the process and reduce hospital visits. The trial is open to patients admitted to the hospital who require heart imaging before undergoing cardioversion. As an unphased trial, it offers patients the chance to contribute to innovative research that could simplify and enhance future heart procedures.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What prior data suggests that contrast enhanced ECG-gated cardiac CT is safe for cardiac imaging?

Research shows that contrast-enhanced ECG-gated cardiac CT (CCT) is generally safe and well-tolerated by patients. This imaging method effectively views the heart and its blood vessels. Strong evidence indicates that CCT can reliably rule out significant heart disease in many patients, making it a dependable tool with a good safety record.

Side effects for patients are rare. Most people handle the procedure well, though some might experience slight discomfort from the contrast dye used during the scan. This discomfort is usually mild and temporary.

Transesophageal echocardiography (TEE), the other procedure being compared, is also common and safe. It involves inserting a probe down the esophagus to obtain detailed images of the heart. Most people tolerate TEE well, although there might be some discomfort from the probe. Serious side effects from TEE are uncommon.

Both CCT and TEE have long been used in medical settings and have well-established safety records. While discomfort can occur, serious risks are rare, making both options generally safe for evaluating heart conditions. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores two different imaging techniques to improve the safety and effectiveness of cardioversion for atrial fibrillation. Unlike the standard Transesophageal Echocardiography (TEE), which is more invasive, the contrast-enhanced ECG-gated cardiac CT (CCT) offers a non-invasive alternative that uses advanced imaging to identify blood clots in the heart with precision. The trial aims to determine if CCT can accurately identify thrombus, potentially reducing the need for TEE in some patients. By comparing these methods, researchers hope to enhance patient safety and streamline the process of preparing for cardioversion.

What evidence suggests that this trial's treatments could be effective for atrial fibrillation?

This trial compares two methods for detecting blood clots in the heart's left atrium before cardioversion for atrial fibrillation. Participants in the CCT arm will undergo a contrast-enhanced ECG-gated cardiac CT (CCT). Research has shown that CCT effectively checks for clots by providing clear heart images and using less radiation than other methods. Participants in the TEE arm will receive transesophageal echocardiography (TEE), which uses sound waves to create detailed heart images and excels at finding clots. Both methods are well-supported by research, but CCT offers a non-invasive option that could simplify patient care by reducing hospital stays. ^{1 2 6 7 8}

Who Is on the Research Team?

Benjamin Chow, MD

Principal Investigator

UOHI

Are You a Good Fit for This Trial?

This trial is for adults over 18 who need imaging of the left atrium before cardioversion, a procedure to correct heart rhythm. Participants must be able to hold their breath for 20 seconds and follow study procedures. It's not for pregnant individuals, those with severe kidney issues (GFR<45ml/min), or certain medical conditions like esophageal problems, unstable heart conditions, or allergies to contrast agents.

Inclusion Criteria

Able and willing to comply with the study procedures

I need a heart scan before a procedure to correct my heart rhythm.

Exclusion Criteria

I cannot undergo a Cardiac CT due to health reasons.

I have a hole in an organ like my stomach or intestines.

I have an unrepaired hole between my windpipe and esophagus.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Imaging

Participants undergo either contrast-enhanced ECG-gated cardiac CT (CCT) or transesophageal echocardiography (TEE) to rule out LA/LAA thrombus

Up to 30 days

1 visit (in-person)

Cardioversion

Participants undergo cardioversion based on imaging results

Up to 30 days

Follow-up

Participants are monitored for safety and effectiveness after cardioversion

Up to 90 days

What Are the Treatments Tested in This Trial?

Interventions

• Contrast enhanced ECG-gated cardiac CT (CCT)
• Transesophageal Echocardiography (TEE)

Trial Overview The study is testing if a type of CT scan can replace an echocardiogram for checking the left atrium in patients with atrial fibrillation before they undergo cardioversion. The goal is to see if this can speed up treatment and reduce hospital stays.

How Is the Trial Designed?

Group I: CCT arm Experimental Treatment 2 Interventions

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.

Group II: TEE arm Active Control 1 Intervention

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.

Contrast enhanced ECG-gated cardiac CT (CCT) is already approved in European Union, United States, Canada for the following indications:

Approved in European Union as Contrast Enhanced Cardiac CT for:

• Coronary artery disease diagnosis
• Cardiac structural anomalies
• Thoracic vascular congenital and acquired diseases
• Preoperative assessment for noncoronary cardiac surgery
• Evaluation of coronary artery bypass grafts

Approved in United States as Contrast Enhanced Cardiac CT for:

• Intermediate pretest probability for coronary artery disease
• Unexplained or atypical chest pain
• Preoperative assessment for transcatheter aortic valve implantation (TAVI/TAVR)
• Evaluation of coronary artery stents >3 mm
• New onset heart failure

Approved in Canada as Contrast Enhanced Cardiac CT for:

• Noninvasive evaluation of coronary artery anomalies and other thoracic vessels
• Symptomatic patients with low/moderate probability of coronary artery disease
• Normal or uninterpretable/non-diagnostic ECG
• Normal or equivocal cardiac biomarkers

Who Is Running the Clinical Trial?

Ottawa Heart Institute Research Corporation

Lead Sponsor

Trials

200

Recruited

95,800+

Published Research Related to This Trial

A multicenter survey of 15 European centers involving 10,419 transesophageal echocardiography (TEE) examinations found that the procedure has a low complication rate, with a mortality rate of only 0.0098%.

The majority of patients (88.7%) underwent TEE without intravenous sedation, and the procedure was generally safe when performed by experienced operators, indicating its practicability in clinical cardiology.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of transesophageal echocardiography. A multicenter survey of 10,419 examinations. Daniel, WG., Erbel, R., Kasper, W., et al.[2022]

In a study of 535 patients undergoing coronary computed tomography angiography (CCTA), automatic image reconstruction using AI-assisted motion correction provided better image quality than manual reconstruction, with average Likert scores of 3.48 versus 3.32.

The automatic reconstruction was particularly effective, as 9.5% of patients required manual intervention due to higher heart rates during scanning, indicating that the AI system can enhance efficiency and reduce the need for radiologist involvement in the CCTA workflow.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Automatic vs manual coronary CT angiography reconstruction for whole-heart coverage CT scanner: a comparison study in general patient population. Yan, C., Liu, J., Yang, X., et al.[2022]

In a study of 126 patients with atrial fibrillation, TEE-guided early cardioversion allowed for a significantly shorter time to cardioversion (0.6 weeks) compared to conventional therapy (4.8 weeks), demonstrating its feasibility and efficiency.

The TEE-guided approach showed no embolic events, while conventional therapy had one peripheral embolic event, suggesting that TEE may reduce the risk of embolism associated with cardioversion.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cardioversion guided by transesophageal echocardiography: the ACUTE Pilot Study. A randomized, controlled trial. Assessment of Cardioversion Using Transesophageal Echocardiography. Klein, AL., Grimm, RA., Black, IW., et al.[2019]

Using a prospectively electrocardiogram-triggered scanning method with an arrhythmia protection algorithm allows for high-quality coronary computed tomographic angiography (CCTA) images in patients with atrial fibrillation, which is typically challenging due to irregular heart rates.

This approach not only improves image quality but also helps in reducing radiation exposure, making CCTA safer and more effective for patients with atrial fibrillation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Advanced adaptive axial-sequential prospectively electrocardiogram-triggered dual-source coronary computed tomographic angiography in a patient with atrial fibrillation. Sidhu, MS., Venkatesh, V., Hoffmann, U., et al.[2016]

In a study involving 40 dogs with congenital heart disease, transesophageal echocardiography (TEE) was found to have a low complication rate, with only mild issues such as mucosal damage in 4 dogs, indicating that TEE is generally safe for use in veterinary practice.

The study highlighted that factors like dog size and the type of probe used can affect the success of TEE, as difficulties were noted in probe placement and imaging in some cases, but overall, major complications were rare.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prospective evaluation of complications associated with transesophageal echocardiography in dogs with congenital heart disease. Stoner, CH., Saunders, AB., Heseltine, JC., et al.[2022]

In a study of 600 patients with atrial fibrillation undergoing transesophageal echocardiography (TEE) before cardioversion, left atrial thrombus (LAT) was found in 11.6% of patients, highlighting the importance of TEE in identifying this risk factor for systemic embolization.

Key clinical factors associated with LAT included a history of myocardial infarction, hypertension, and a higher CHADS(2) score, while lower left atrial emptying velocity was the strongest independent predictor of LAT, suggesting that TEE is crucial for assessing embolization risk in AF patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prevalence and predictors of left atrial thrombus in patients with atrial fibrillation: is transesophageal echocardiography necessary before cardioversion? Malik, R., Alyeshmerni, DM., Wang, Z., et al.[2016]

Cardiac computed tomography angiography (CCTA) is more effective than transesophageal echocardiography (TEE) in detecting left atrial appendage (LAA) patency after device closure, with a significant odds ratio of 2.79 based on a meta-analysis of six studies.

Both CCTA and TEE showed no significant difference in detecting peridevice gaps of 5 mm or more, suggesting that while CCTA is better for assessing LAA patency, both methods are comparable for evaluating device gaps.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

CT assessment of the left atrial appendage post-transcatheter occlusion - A systematic review and meta analysis. Banga, S., Osman, M., Sengupta, PP., et al.[2021]

In a study of 78 congenital heart disease patients, cardiac computed tomography angiography (CCTA) demonstrated excellent diagnostic performance with a sensitivity of 97.5% and specificity of 100%, making it a highly reliable tool for pre-operative evaluation.

CCTA not only provided critical information for surgical planning but also had a low radiation exposure of 1.41 mSv per study, highlighting its safety and practicality in managing congenital heart disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cardiac computed tomography angiography in the pre-operative assessment of congenital heart disease in Thailand. Chaosuwannakit, N., Makarawate, P., Jantachum, N.[2022]

In a study of 120 patients (60 with atrial fibrillation and 60 controls), the optimal reconstruction phase for coronary computed tomographic angiography (CCTA) in most patients with atrial fibrillation was found to be end-diastole, which helps reduce motion artefacts.

For patients with higher heart rates, the end-systolic phase was more optimal, indicating that controlling heart rate and using ECG monitoring are important for achieving high-quality images in CCTA.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

256-Slice coronary computed tomographic angiography in patients with atrial fibrillation: optimal reconstruction phase and image quality. Oda, S., Honda, K., Yoshimura, A., et al.[2020]

A predictive model for successful prospectively gated coronary computed tomographic angiography (CCTA) was developed, identifying key factors such as heart rate, heart rate variability, body mass index, and coronary calcium score that influence image quality.

In a study of 162 patients, the model showed that by using these predictors, only 5 segments in 4 additional patients were nondiagnostic, while the mean radiation dose for the procedure was low at 2.2 mSv, indicating a safe and effective approach to CCTA.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Predicting success of prospective and retrospective gating with dual-source coronary computed tomography angiography: development of selection criteria and initial experience. Gutstein, A., Wolak, A., Lee, C., et al.[2019]

In a study of 32 patients with ischemic stroke, cardiac-gated computerized tomography (CGCT) demonstrated a high correlation with transesophageal echocardiography (TEE) in detecting aortic atherosclerosis (AA), with an intraclass correlation of 0.93.

CGCT was more effective than TEE in identifying smaller atheromas and provided better details about the shape of atheromatous plaques, suggesting it may be a superior tool for evaluating AA in stroke patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparing multislice electrocardiogram-gated spiral computerized tomography and transesophageal echocardiography in evaluating aortic atheroma in patients with acute ischemic stroke. Hussain, SI., Gilkeson, RC., Suarez, JI., et al.[2019]

ECG-gated coronary CT angiography (CCTA) is an effective diagnostic tool for identifying post-procedural complications in heart and thoracic aorta surgeries, with a 9.2% complication rate observed in a study of 294 patients over three years.

The most common complications detected included coronary intimal dissection after percutaneous coronary interventions and right atrial or ventricular perforation after pacemaker implantation, highlighting the importance of CCTA in guiding patient management post-surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

ECG-Gated CCTA in the Assessment of Post-Procedural Complications. Liguori, C., Lassandro, G., Ferrandino, G., et al.[2023]

In a study of 283 patients with atrial fibrillation, a new scanning protocol (R+800 ms) was successfully used in 95% of cases, resulting in motion-free images for 91% of patients, which is crucial for accurate diagnosis.

The R+800 ms protocol not only provided high-quality images but also resulted in a lower radiation exposure compared to the alternative R+210 ms protocol, enhancing the safety of the procedure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Coronary Computed Tomography Angiography for Patients with Atrial Fibrillation: Feasibility of Prospective Electrocardiography-gated Diastolic Acquisition with a Manual Exposure-termination Technique]. Matsutani, H., Amanuma, M., Sano, T., et al.[2018]

In a study of 33 patients with atrial fibrillation, using electrocardiogram (ECG) editing techniques significantly improved the image quality of coronary computed tomography angiography (CCTA), especially when short RR intervals were deleted.

The best image quality was achieved by reconstructing images using the 'R-absolute time method' or 'R+absolute time method', which outperformed traditional methods like Phase Navi, indicating that these ECG-editing techniques are effective for enhancing CCTA in patients with Afib.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Reconstruction of coronary 64-multidetector-row computed tomography angiography in patients with atrial fibrillation: delete short RR intervals using electorocardiogram]. Matsutani, H., Sano, T., Kondo, T., et al.[2019]

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