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.
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
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)
Parallel
Cardiac computed tomography angiography
Diagnostic testPatients 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.
Standard of care management
Other interventionPatients 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.
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
Composite objective outcomes
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 releated reason 4. Repeat presentation to hospital for a cardiac or AF related reason
All-cause death
Death from any cause
Cardiovascular death
Death due to a cardiovascular cause
Stroke, transient ischemic attack, or systemic embolism
Stroke is defined as a central nervous system infarction of the brain, spinal cord, or retina in a vascular distribution based on pathologic, imaging, or clinical evidence with symptoms persisting for ≥24 hours or until death. Transient ischemic attack is defined as a transient episode of neurologic dysfunction due to focal brain, spinal cord, or retinal ischemia without acute infarction or tissue injury. Systemic embolism is defined as an abrupt vascular insufficiency associated with clinical or radiologic evidence of arterial occlusion in the absence of other likely mechanisms.
Cost effectiveness
Cost effectiveness between CCT strategy and standard of care
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