Using a quick CT scan to check for left atrial clots before cardioversion in the Emergency Department

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

This will test whether a rapid cardiac CT in the ED to look for left atrial clots lets people with symptomatic atrial fibrillation or flutter have safe same‑day cardioversion instead of being admitted or delayed.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 190 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Ottawa Heart Institute Research Corporation (Academic / other)
• Drugs / interventions: radiation
• Locations: 1 site (Ottawa, Ontario)
• Trial ID: NCT07002450 on ClinicalTrials.gov

What this trial studies

This randomized multicenter trial compares cardiac computed tomography angiography (CCT)–facilitated cardioversion in the emergency department to current standard care for patients with symptomatic atrial fibrillation or flutter who need left atrial imaging before cardioversion. Patients randomized to the CCT arm will have a CT to rule out thrombus and, if no clot is seen, may undergo immediate chemical or electrical cardioversion in the ED; the control arm follows local standard practice (which may include TEE, admission, or outpatient anticoagulation). The study will measure hospital admission rates, repeat ED presentations, and patient quality of life with follow-up at 30 days. CCT is more widely available than TEE and has shown high sensitivity and specificity for detecting left atrial thrombus in diagnostic studies, so this trial tests the pathway impact of using CCT in real-world ED care.

Who should consider this trial

Good fit: Adults (≥18) with symptomatic atrial fibrillation or atrial flutter who require left atrial imaging before cardioversion and who are hemodynamically stable and able to receive iodinated contrast and hold their breath for the scan are ideal candidates.

Not a fit: Patients who need emergency cardioversion for instability or who cannot undergo CCT (severe renal impairment, contrast allergy, pregnancy, or inability to breath‑hold) are unlikely to benefit from this CT‑facilitated approach.

Why it matters

Potential benefit: If successful, eligible patients could be cardioverted safely in the ED after a rapid CT, reducing hospital admissions, repeat visits, and time spent in symptomatic arrhythmia.

How similar studies have performed: Diagnostic studies show CCT has high sensitivity and specificity compared with TEE for detecting atrial thrombus, but randomized trials of ED CCT‑guided cardioversion are limited, making this approach relatively novel in trial form.

Eligibility criteria

Inclusion Criteria:

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

Exclusion Criteria:

1. 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
2. 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)

Where this trial is running

Ottawa, Ontario

• The Ottawa Hospital Civic Campus — Ottawa, Ontario, Canada (Recruiting)

Study contacts

• Principal investigator: Benjamin Chow, MD PhD FRCPC FACC FESC FA — Ottawa Heart Institute Research Corporation
• Study coordinator: Farrah Ahmed

Conditions Atrial Fibrillation; Atrial Flutter; Cardiac computed tomography angiography; Cardioversion; Atrial flutter; Atrial fibrillation