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. 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 and neurological assessment. Additional testing depends on risk stratification. High-risk patients (those with structural heart disease, abnormal ECG, older age, or concerning features) should undergo echocardiography to assess structural abnormalities and cardiac monitoring for at least 24-48 hours. If cardiac causes are suspected, exercise stress testing or electrophysiology studies may be indicated. For recurrent unexplained syncope, extended cardiac monitoring with implantable loop recorders for up to 3 years may be necessary. If orthostatic hypotension is suspected, tilt-table testing can be useful. Carotid sinus massage may be performed in patients over 40 with recurrent unexplained syncope. Laboratory tests should include complete blood count, electrolytes, glucose, and cardiac biomarkers if cardiac ischemia is suspected. Neuroimaging (CT or MRI) is only indicated if neurological examination is abnormal or if seizure is suspected, as stated in the 2021 guidelines 1. This approach helps identify the underlying cause, which is essential for appropriate management and prevention of recurrence.

Some key points to consider in the workup of syncope include:

• A thorough history and physical examination are essential in identifying the underlying cause of syncope
• A 12-lead ECG should be performed on all patients to detect arrhythmias or abnormality indicative of higher risk for arrhythmia
• Additional testing, such as echocardiography, cardiac monitoring, and electrophysiology studies, should be guided by risk stratification and clinical presentation
• Neuroimaging should only be performed if there are abnormal neurological examination findings or if seizure is suspected, as recommended by the American College of Radiology Appropriateness Criteria 1
• The use of implantable loop recorders and tilt-table testing may be useful in certain cases, such as recurrent unexplained syncope or suspected orthostatic hypotension, as suggested by the European Heart Journal guidelines 1.

Overall, a systematic and stepwise approach to the evaluation of syncope, as outlined in the guidelines from the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society 1, is essential in identifying the underlying cause and guiding management.

From the Research

Syncope Workup

• Syncope is an abrupt, transient, and complete loss of consciousness associated with an inability to maintain postural tone, with rapid and spontaneous recovery 2.
• The primary classifications of syncope are cardiac, reflex (neurogenic), and orthostatic 2, 3.
• Evaluation of syncope focuses on:
  • History
  • Physical examination (including orthostatic blood pressure measurements)
  • Electrocardiographic results 2, 3, 4, 5, 6
• Additional testing may be considered if the findings are inconclusive and indicate possible adverse outcomes, but testing has limited utility except in patients with cardiac syncope 2.
• Prolonged electrocardiographic monitoring, stress testing, and echocardiography may be beneficial in patients at higher risk of adverse outcomes from cardiac syncope 2.
• Neuroimaging should be ordered only when findings suggest a neurologic event or a head injury is suspected 2, 3.
• Laboratory tests may be ordered based on history and physical examination findings 2, 3.

Risk Stratification

• Patients are designated as having lower or higher risk of adverse outcomes according to history, physical examination, and electrocardiographic results 2, 3.
• Risk stratification tools, such as the Canadian Syncope Risk Score, may be beneficial in this decision 2.
• Low-risk patients with a single episode of syncope can often be reassured with no further investigation 3.
• 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.

Diagnostic Approach

• A standardized approach to syncope evaluation reduces hospital admissions and medical costs, and increases diagnostic accuracy 3.
• Syncope units have been shown to improve the rate of diagnosis while reducing cost and thus are highly recommended 4.
• A careful, well-conducted medical history focused on the suspected syncopal event is crucial for the diagnosis 6.
• A 12-lead electrocardiogram (ECG) is the only instrumental test recommended for the initial evaluation of patients with suspected syncope 6.