What is the initial workup for a patient presenting with syncope?

From the Guidelines

The initial workup for a patient presenting with syncope should include a thorough history, physical examination, and targeted diagnostic tests, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. Begin with a detailed history focusing on the circumstances surrounding the event, prodromal symptoms, position during the episode, duration, recovery period, and any associated symptoms like chest pain or palpitations. Obtain a complete medication history, as drugs like antihypertensives, antiarrhythmics, and psychiatric medications can contribute to syncope. The physical examination should include:

• Orthostatic vital signs (measuring blood pressure and heart rate while lying, sitting, and standing)
• A comprehensive cardiovascular assessment including heart sounds and carotid bruits
• A neurological examination. An electrocardiogram (ECG) is essential for all syncope patients to evaluate for arrhythmias, conduction abnormalities, or signs of structural heart disease, as stated in the guidelines on management (diagnosis and treatment) of syncope-update 2004 1. Laboratory tests should include complete blood count, basic metabolic panel, and cardiac enzymes if cardiac etiology is suspected. For patients with suspected cardiac syncope, additional tests may include:
• Echocardiography, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1
• Ambulatory cardiac monitoring (Holter or event monitor)
• Exercise stress testing. Neuroimaging (CT or MRI) is generally not indicated unless there are focal neurological findings or suspected seizure activity, as stated in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. This systematic approach helps identify the underlying cause of syncope, which is crucial for appropriate management, as syncope can range from benign vasovagal episodes to life-threatening cardiac conditions requiring immediate intervention. Some key points to consider in the initial evaluation include:
• Differentiating true syncope from ‘non-syncopal’ conditions associated with real or apparent transient loss of consciousness, as discussed in the guidelines on management (diagnosis and treatment) of syncope-update 2004 1
• Assessing the medication list for agents associated with proarrhythmia, as recommended by the AHA/ACCF scientific statement on the evaluation of syncope 1.
• Evaluating the patient's history and physical examination to determine the risk of cardiovascular events or death, as stated in the guidelines for the diagnosis and management of syncope (version 2009) 1. By following this approach, clinicians can provide effective and targeted care for patients presenting with syncope, prioritizing morbidity, mortality, and quality of life as the primary outcomes.

From the Research

Initial Workup for Syncope

The initial workup for a patient presenting with syncope should focus on history, physical examination, and electrocardiogram (ECG) examination 2.

Key Components of Initial Workup

• History: A careful, well-conducted medical history focused on the suspected syncopal event is crucial for the diagnosis 3.
• Physical examination: Information obtained from physical examination should be used to guide the selection of further high yield tests 2.
• Electrocardiogram (ECG): A 12-lead ECG is the only instrumental test recommended for the initial evaluation of patients with suspected syncope 3. The ECG may disclose an arrhythmia associated with a high likelihood of syncope, avoiding further evaluations and permitting institution of specific treatment in some patients 3.

Further Testing

Further testing, such as Holter monitoring, head-up tilt table test (HUTT), treadmill test, CT/MRI of the brain, electroencephalography, carotid sinus massage, coronary angiography, electrophysiological study, and carotid Doppler ultrasound, may be selected based on the findings from medical history, physical examination, ECG, and echocardiography findings 2.

Diagnostic Yield of Various Tests

• ECG: May identify patients with high likelihood of cardiac syncope due to arrhythmic or cardiopulmonary disorder 3.
• Holter monitoring: May show symptomatic correlation with arrhythmias, but this is rarely found (only 4% of patients) 4.
• Electrophysiologic studies: More likely to be abnormal in patients with underlying heart disease or those who have abnormalities on surface electrocardiogram 4.
• Upright tilt testing: May induce vasovagal syncope in patients with syncope of unknown cause, with a positive response found in 26% to 87% of patients undergoing this type of testing 4.