From the Guidelines
The workup for syncope should begin with a thorough history, physical examination, and 12-lead ECG for all patients, as recommended by the most recent guidelines 1. The history should focus on circumstances surrounding the event, prodromal symptoms, position at onset, and any associated symptoms.
- Physical examination should include:
- Orthostatic vital signs (measuring blood pressure and heart rate supine, then after standing for 1 and 3 minutes)
- Cardiac examination
- Neurological assessment Additional first-line testing includes basic laboratory studies (complete blood count, electrolytes, glucose, renal function) to rule out metabolic causes.
- If cardiac etiology is suspected based on history, examination, or ECG abnormalities, further cardiac evaluation with:
- Echocardiography
- Ambulatory cardiac monitoring (24-hour to 30-day event monitors depending on frequency of symptoms)
- Possibly exercise stress testing should be performed, as suggested by the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society 1. For recurrent unexplained syncope, tilt-table testing may help diagnose vasovagal syncope, as recommended by the European Heart Journal guidelines 1. In selected cases with suspected seizures, electroencephalography and brain imaging might be warranted. Carotid sinus massage can be considered in older patients without carotid bruits or history of cerebrovascular disease. The workup should be guided by the initial evaluation findings, as extensive testing in all patients is not cost-effective and rarely yields diagnostic information beyond what a careful history, physical examination, and ECG provide, as emphasized by the Journal of the American College of Radiology 1.
From the Research
Syncope Workup
- The evaluation of syncope begins with a careful history, physical examination, and electrocardiography 2
- A standardized approach to syncope evaluation reduces hospital admissions and medical costs, and increases diagnostic accuracy 3
- The initial assessment for all patients presenting with syncope includes a detailed history, physical examination, and electrocardiography 3
Classification of Syncope
- Syncope can be classified into four categories: reflex mediated, cardiac, orthostatic, and cerebrovascular 2
- Neurally mediated syncope is the most common type and has a benign course, whereas cardiac syncope is associated with increased morbidity and mortality 3
- Reflex syncope can be categorised into vasovagal syncope, situational syncope, carotid sinus syncope, and atypical reflex syncope 4
Diagnostic Evaluation
- Additional testing should be based on the initial clinical evaluation 2
- Older patients and those with underlying organic heart disease or abnormal electrocardiograms generally will need additional cardiac evaluation, which may include prolonged electrocardiographic monitoring, echocardiography, and exercise stress testing 2
- The use of tests such as head computed tomography, magnetic resonance imaging, carotid and transcranial ultrasonography, and electroencephalography to detect cerebrovascular causes of syncope should be reserved for those few patients with syncope whose history suggests a neurologic event or who have focal neurologic signs or symptoms 2
- A 12-lead electrocardiogram (ECG) is the only instrumental test recommended for the initial evaluation of patients with suspected syncope 5
Risk Stratification
- Useful clinical rules to assess the short-term risk of death and the need for immediate hospitalization include the San Francisco Syncope Rule and the Risk Stratification of Syncope in the Emergency Department rule 6
- Patients with cardiovascular disease, abnormal electrocardiography, or family history of sudden death, and those presenting with unexplained syncope should be hospitalized for further diagnostic evaluation 6
- High-risk patients with cardiovascular or structural heart disease, history concerning for arrhythmia, abnormal electrocardiographic findings, or severe comorbidities should be admitted to the hospital for further evaluation 3