From the Guidelines
To evaluate for cardioembolic causes of a patient's stroke, I recommend a comprehensive cardiac workup that includes electrocardiogram (ECG), transthoracic echocardiogram (TTE), and prolonged cardiac monitoring, as supported by the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack 1.
Diagnostic Approach
The diagnostic approach should begin with a 12-lead ECG to identify atrial fibrillation, flutter, or evidence of prior myocardial infarction, as recommended by the American Heart Association/American Stroke Association guideline 1.
- This initial step is crucial for identifying potential cardioembolic sources.
- Follow-up tests may include:
- Transthoracic echocardiogram (TTE) to assess for left ventricular thrombus, valvular disease, patent foramen ovale, or other structural abnormalities.
- Transesophageal echocardiogram (TEE) for superior visualization of the left atrium, left atrial appendage, and thoracic aorta, particularly in cases where the initial evaluation is unrevealing but suspicion remains high.
- Prolonged cardiac monitoring for at least 24-72 hours in the acute setting, with consideration for prolonged monitoring (14-30 days) using Holter monitors or implantable loop recorders in cryptogenic stroke cases, as suggested by the Canadian stroke best practice recommendations 1.
Additional Tests
Additional tests may include:
- Cardiac MRI if myocardial disease is suspected.
- Laboratory studies such as troponin levels, brain natriuretic peptide, and lipid profiles.
- Imaging of the cervical arteries, such as CTA or MRA, to evaluate for stenosis and/or occlusion, as recommended by the American Society of Neuroradiology, the American College of Radiology, and the Society of Neurointerventional Surgery 1.
Importance of Comprehensive Workup
This systematic approach is crucial because cardioembolic strokes account for approximately 20-30% of ischemic strokes, and identifying the source guides appropriate secondary prevention strategies, particularly anticoagulation for conditions like atrial fibrillation, where warfarin, direct oral anticoagulants (apixaban 5mg twice daily, rivaroxaban 20mg daily, dabigatran 150mg twice daily, or edoxaban 60mg daily) significantly reduce recurrence risk, as supported by the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack 1.
From the Research
Diagnostic Approaches for Cardioembolic Stroke
The diagnostic approaches for evaluating cardioembolic causes of a patient's cerebrovascular accident (CVA) or stroke include:
- Medical history and physical examination 2
- 12-lead ECG recording 2
- Rhythm monitoring for 72 hours 2
- Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) 2, 3, 4
- Extended cardiac work-up, such as MRI/CT, and prolonged rhythm monitoring, in selected patients based on diagnostic findings 2
- Biomarkers, such as BNP and NT-proBNP, which have been shown to be helpful in diagnosing cardioembolic stroke and predicting the risk of stroke recurrence 5
Role of Echocardiography
Echocardiography is a crucial diagnostic tool in evaluating cardioembolic stroke, with TTE and TEE being the most commonly used techniques 3, 4.
- TEE is superior to TTE in detecting cardiac sources of embolism (CSE) 3
- TTE should be used for all patients admitted for ischemic stroke, while TEE should be limited to younger patients or those with a high suspicion of cardioembolic origin 3
Other Diagnostic Tools
Other diagnostic tools, such as cardiac computed tomography and magnetic resonance imaging, can provide additional information in specific situations, but are not recommended as first-line modalities 4.