What is the workup for syncope (fainting)?

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, an electrocardiogram (ECG), and basic laboratory tests including complete blood count, basic metabolic panel, and cardiac enzymes.

• Key components of the history include:
  • Circumstances surrounding the event
  • Prodromal symptoms
  • Associated features such as palpitations, chest pain, or neurological symptoms
• The physical examination should include:
  • Orthostatic vital signs
  • Cardiac examination
  • Neurological examination If cardiac causes are suspected, an echocardiogram should be performed to assess structural heart disease and ejection fraction.
• Cardiac causes of syncope include:
  • Arrhythmias such as bradycardia or tachycardia
  • Structural heart disease such as valvular disease or cardiomyopathy
  • Cardiac ischemia or infarction For recurrent unexplained syncope, ambulatory cardiac monitoring is recommended, ranging from 24-48 hour Holter monitoring to 30-day event monitors or implantable loop recorders depending on the frequency of episodes, as suggested by the European Heart Journal guidelines 1.
• The choice of monitoring device depends on:
  • Frequency of episodes
  • Duration of episodes
  • Presence of underlying cardiac disease Tilt table testing may be useful for suspected vasovagal syncope, while exercise stress testing is appropriate when exertional syncope is reported.
• Additional testing may include:
  • Carotid sinus massage in older patients with suspected carotid sinus hypersensitivity
  • Neurological evaluation including electroencephalogram (EEG) and brain imaging if seizure activity is suspected or there are focal neurological findings The depth of investigation should be guided by the initial risk stratification, with high-risk features such as abnormal ECG, history of heart disease, sudden onset without warning, or syncope during exertion warranting more extensive cardiac evaluation and possible hospitalization.
• High-risk features include:
  • Abnormal ECG
  • History of heart disease
  • Sudden onset without warning
  • Syncope during exertion
  • Presence of underlying cardiac disease

From the Research

Evaluation of Syncope

The evaluation of syncope focuses on history, physical examination, and electrocardiographic results 2. A thorough history and physical examination, including orthostatic blood pressure measurements, are crucial for making the diagnosis 3. The classification of syncope is based on the underlying pathophysiological mechanism causing the event, and includes:

• Cardiac syncope
• Reflex (neurogenic) syncope
• Orthostatic syncope

Diagnostic Tests

Additional testing may be considered if the findings are inconclusive and indicate possible adverse outcomes 2. Diagnostic tests that may be beneficial in patients with cardiac syncope include:

• Prolonged electrocardiographic monitoring
• Stress testing
• Echocardiography Neuroimaging should be ordered only when findings suggest a neurologic event or a head injury is suspected 2. Laboratory tests may be ordered based on history and physical examination findings, such as hemoglobin measurement if gastrointestinal bleeding is suspected 2.

Risk Stratification

Patients are designated as having lower or higher risk of adverse outcomes according to history, physical examination, and electrocardiographic results 2. Risk stratification tools, such as the Canadian Syncope Risk Score, may be beneficial in this decision 2. Short-term risk assessment should be performed to determine the need for admission 3. If the short-term risk is high, inpatient evaluation is needed, while outpatient evaluation is recommended if the short-term risk is low 3.

Management

The main objectives of management are to prolong survival, limit physical injuries, and prevent recurrences 4. In patients with reflex or orthostatic syncope, it is essential to address any exacerbating medication and provide general measures to increase blood pressure, such as physical counter-pressure maneuvers 4. Where heart disease is found to be the cause of the syncope, a specialist opinion is warranted, and the problem should be corrected if possible 4. Syncope units have been shown to improve the rate of diagnosis while reducing cost and are highly recommended 3.