What is the appropriate workup for syncope (fainting)?

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
  • Cardiac assessment to evaluate for structural heart disease
  • Neurological assessment to exclude symptoms or signs of a separate neurologic process Additional testing depends on risk stratification, with high-risk patients (those with structural heart disease, abnormal ECG, older age, or concerning features) undergoing further evaluation 1.
• High-risk patients should undergo:
  • Echocardiography to assess structural abnormalities
  • Cardiac monitoring for at least 24-48 hours
• If cardiac causes are suspected, consider:
  • Exercise stress testing
  • Longer-term monitoring with event recorders or implantable loop recorders (for recurrent unexplained syncope)
  • Electrophysiology studies for those with suspected arrhythmias For suspected vasovagal syncope, tilt-table testing may be useful 1.
• Laboratory tests should include:
  • Complete blood count
  • Electrolytes
  • Glucose
  • Cardiac biomarkers if cardiac ischemia is suspected Brain imaging (CT or MRI) and EEG are only indicated if neurological causes are suspected based on history or examination findings, as the yield of these tests is low in uncomplicated syncope 1. Carotid sinus massage may be considered in patients over 40 with suspected carotid sinus hypersensitivity, but should be avoided in those with carotid bruits or history of stroke. This systematic approach helps identify the underlying cause of syncope, which is essential for appropriate management and prevention of recurrence.

From the Research

Syncope Workup

• Syncope is a complex presenting symptom defined by a transient loss of consciousness, usually accompanied by falling, and with spontaneous recovery 2.
• The evaluation of syncope begins with a careful history, physical examination, and electrocardiography, with additional testing based on the initial clinical evaluation 2, 3, 4.
• Syncope can be classified into four categories: reflex mediated, cardiac, orthostatic, and cerebrovascular, with cardiac cause associated with significantly higher rates of morbidity and mortality than other causes 2, 3, 4, 5.

Diagnostic Approach

• A structured approach to the patient with syncope is required, with history-taking being the most important aspect of the clinical assessment 5.
• The classification of syncope is based on the underlying pathophysiological mechanism causing the event, including cardiac, orthostatic, and reflex (neurally mediated) mechanisms 5.
• A 12-lead electrocardiogram (ECG) is the only instrumental test recommended for the initial evaluation of patients with suspected syncope, and may disclose an arrhythmia associated with a high likelihood of syncope 6.

Testing and Risk Stratification

• Additional testing, such as prolonged electrocardiographic monitoring, stress testing, and echocardiography, may be beneficial in patients at higher risk of adverse outcomes from cardiac syncope 2, 3, 4.
• Risk stratification tools, such as the Canadian Syncope Risk Score, may be beneficial in informing decisions regarding hospital admission 4.
• Neuroimaging should be ordered only when findings suggest a neurologic event or a head injury is suspected, and laboratory tests may be ordered based on history and physical examination findings 2, 4.

Management

• Patients with life-threatening causes of syncope should be managed urgently and appropriately, and those with reflex or orthostatic syncope should have any exacerbating medication addressed and be provided with general measures to increase blood pressure 5.
• The main objectives of management are to prolong survival, limit physical injuries, and prevent recurrences, which can only be done if a patient is appropriately assessed at presentation, investigated as clinically indicated, and subsequently referred to a cardiologist for appropriate management 5.