How to diagnose neurogenic (neurocardiogenic) syncope?

From the Guidelines

Neurogenic syncope can be diagnosed through a combination of clinical evaluation and specific tests, starting with a thorough medical history and physical examination, including orthostatic vital signs, and utilizing tests such as electrocardiogram (ECG) and occasionally tilt table testing, as recommended by the most recent guidelines 1. The diagnostic approach to neurogenic syncope involves several key steps:

• A thorough medical history focusing on syncope triggers, associated symptoms, and frequency of episodes
• Physical examination, including orthostatic vital signs, measuring blood pressure and heart rate while lying down and then standing
• Utilization of an electrocardiogram (ECG) to detect arrhythmias or abnormality indicative of higher risk for arrhythmia, as suggested by multisociety guidelines 1
• Consideration of tilt table testing, although its sensitivity and specificity depend on the technique used, and it may contribute little to establishing the diagnosis in patients with a negative evaluation and no evidence of ischemia or structurally normal heart 1
• Other useful tests may include ambulatory blood pressure monitoring, echocardiogram, and occasionally blood tests to rule out other causes
• Holter monitoring may be recommended to detect any cardiac rhythm abnormalities during daily activities It is essential to note that the mainstay of syncope and presyncope assessment is a detailed history and physical examination, and additional testing should be limited to select patients based on clinical assessment, as nonfocused testing does not improve diagnostic yield but increases hospitalization rate and cost 1.

From the Research

Diagnosis of Neurogenic (Neurocardiogenic) Syncope

To diagnose neurogenic (neurocardiogenic) syncope, the following steps can be taken:

• A careful history and physical examination are essential in evaluating syncope 2, 3, 4, 5, 6
• Classification of syncope into four categories: reflex mediated, cardiac, orthostatic, and cerebrovascular can help in identifying the cause 2
• Electrocardiography is a crucial initial test in the evaluation of syncope 2, 3
• Additional testing such as head-up tilt-table testing and carotid sinus massage may be performed to diagnose neurogenic reflex-mediated syncope 2
• Tests such as head computed tomography, magnetic resonance imaging, carotid and transcranial ultrasonography, and electroencephalography may be reserved for patients with a history suggesting a neurologic event or those with focal neurologic signs or symptoms 2

Evaluation Approach

The evaluation approach for syncope includes:

• History-taking as the most important aspect of the clinical assessment 4
• Classification of syncope based on the underlying pathophysiological mechanism causing the event 4
• Identification of the precise cause to implement a mechanism-specific and effective therapeutic strategy 4
• Quantification of the risk to the patient, which depends on the underlying disease rather than the mechanism of the syncope 4

Specific Considerations

Specific considerations in the diagnosis and management of neurogenic syncope include:

• Older patients and those with underlying organic heart disease or abnormal electrocardiograms may require additional cardiac evaluation 2
• 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 3
• Patients with neurally mediated or orthostatic syncope usually require no additional testing 3