From the Guidelines
The workup for syncope should begin with a thorough history and physical examination, focusing on the circumstances surrounding the event, prodromal symptoms, and any associated features, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. The initial evaluation should include orthostatic vital signs, electrocardiogram (ECG), and basic laboratory tests (complete blood count, electrolytes, glucose, and renal function) to identify potential cardiac or non-cardiac causes of syncope.
- Key components of the history and physical examination include:
- Circumstances surrounding the event, such as precipitating factors or prodromal symptoms
- Associated features, such as palpitations, chest pain, or neurological symptoms
- Past medical history, including cardiovascular or neurological conditions
- Initial testing should also include:
- Orthostatic vital signs to evaluate for orthostatic hypotension
- ECG to evaluate for cardiac arrhythmias or conduction abnormalities
- Basic laboratory tests to evaluate for electrolyte imbalances, anemia, or other potential causes of syncope If cardiac causes are suspected, additional tests may include:
- Echocardiography to evaluate for structural heart disease
- Ambulatory cardiac monitoring (Holter or event monitor for 24 hours to 30 days depending on frequency of symptoms) to evaluate for arrhythmias
- Exercise stress testing to evaluate for ischemia or arrhythmias For recurrent unexplained syncope, extended cardiac monitoring with implantable loop recorders may be warranted 1. Neurological evaluation with electroencephalogram (EEG) or brain imaging (CT or MRI) should be considered if seizure activity is suspected or if there are focal neurological findings. Tilt-table testing can help diagnose vasovagal syncope when history is suggestive but not diagnostic. Carotid sinus massage may be performed in older patients to evaluate for carotid sinus hypersensitivity, though this should be done with caution and cardiac monitoring, as recommended by the European Heart Journal guidelines on management of syncope-update 2004 1. The workup should be tailored to the patient's presentation, as syncope has many potential causes including cardiac (arrhythmias, structural heart disease), neurological (seizures, TIA), and reflex-mediated (vasovagal, situational) etiologies. Identifying the underlying cause is crucial for appropriate management and prevention of recurrence.
From the Research
Evaluation of Syncope
The evaluation of syncope involves a thorough history, physical examination, and electrocardiographic results 2, 3, 4. The primary goal is to identify the underlying cause of syncope, which can be classified as cardiac, reflex (neurogenic), or orthostatic 2, 3.
Initial Assessment
The initial assessment includes:
- A detailed history to identify the most likely diagnosis 4, 5
- Physical examination, including orthostatic blood pressure measurements 2, 6
- Electrocardiographic results to identify potential cardiac causes 2, 3, 5
Risk Stratification
Risk stratification is crucial to determine the need for hospital admission 2, 3, 6. Patients can be designated as having lower or higher risk of adverse outcomes based on history, physical examination, and electrocardiographic results 2. Risk stratification tools, such as the Canadian Syncope Risk Score, may be beneficial in this decision 2.
Diagnostic Testing
Diagnostic testing, such as laboratory tests and neuroimaging, should be ordered only if clinically indicated 2, 3, 6. Prolonged electrocardiographic monitoring, stress testing, and echocardiography may be beneficial in patients at higher risk of adverse outcomes from cardiac syncope 2.
Management
The management of syncope depends on the underlying cause 3, 6. Patients with cardiac syncope may require cardiac device placement or ablation, while those with reflex or orthostatic hypotension syncope may require supportive treatment or pharmacotherapy 3, 6. Syncope units have been shown to improve the rate of diagnosis while reducing cost and are highly recommended 6.