From the Guidelines
A comprehensive workup for syncope includes a detailed history, physical examination, and targeted investigations, as outlined in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1.
Key Components of the Workup
- Begin with a thorough history focusing on circumstances surrounding the event, prodromal symptoms, position, exertion, and associated symptoms.
- Physical examination should include:
- Orthostatic vital signs (measuring blood pressure and heart rate while lying, sitting, and standing)
- Cardiovascular assessment
- Neurological examination
- Initial testing should include:
- A 12-lead ECG to identify arrhythmias, conduction abnormalities, or structural heart disease
- Laboratory tests to assess for anemia, electrolyte disturbances, and hypoglycemia
Additional Testing Based on Clinical Suspicion
- For suspected cardiac causes, additional testing may include:
- Echocardiography to evaluate structural heart disease
- Ambulatory cardiac monitoring (24-hour Holter, event recorder, or implantable loop recorder) for intermittent arrhythmias
- Exercise stress testing if exertional syncope is suspected
- For suspected neurological causes, consider:
- EEG
- Brain imaging
- Carotid ultrasound
- Tilt-table testing may help diagnose vasovagal syncope in unclear cases
Special Considerations
- For older adults or those with risk factors for cardiac disease, more extensive cardiac evaluation is warranted
- The systematic approach helps identify the underlying cause, which is essential for appropriate management, as syncope can range from benign conditions to life-threatening cardiac disorders requiring immediate intervention, as noted in guidelines from the European Heart Journal 1.
From the Research
Evaluation of Syncope
The evaluation of syncope begins with a careful history, physical examination, and electrocardiography 2. Additional testing should be based on the initial clinical evaluation. The primary classifications of syncope are:
- Cardiac
- Reflex (neurogenic)
- Orthostatic
Diagnostic Testing
Diagnostic testing for syncope includes:
- Electrocardiography (ECG) as the only instrumental test recommended for the initial evaluation of patients with suspected syncope 3
- Prolonged electrocardiographic monitoring, stress testing, and echocardiography may be beneficial in patients at higher risk of adverse outcomes from cardiac syncope 2, 4
- Neuroimaging should be ordered only when findings suggest a neurologic event or a head injury is suspected 2, 4
- Laboratory tests may be ordered based on history and physical examination findings (e.g., hemoglobin measurement if gastrointestinal bleeding is suspected) 4
- Tilt-table testing and carotid sinus massage for suspected reflex-mediated syncope 2
- Holter monitoring, or intracardiac electrophysiologic studies for patients with suspected cardiac syncope 5
Risk Stratification
Patients are designated as having lower or higher risk of adverse outcomes according to history, physical examination, and electrocardiographic results, which can inform decisions regarding hospital admission 4, 6. Risk stratification tools, such as the Canadian Syncope Risk Score, may be beneficial in this decision 4.
Hospitalization
Hospitalization may be indicated for patients at high risk for cardiac syncope (those with an abnormal electrocardiogram, organic heart disease, chest pain, history of arrhythmia, age > 70 years) or with acute neurologic signs 5. Syncope units have been shown to improve the rate of diagnosis while reducing cost and thus are highly recommended 6.