The role of Psychological Factors in the Aetiology and Treatment of Vasovagal Syncope

Syncope is a sudden transient loss of consciousness with loss of postural tone, followed by spontaneous recovery1. Around 30 percent of the general population have one syncopal event in their lifetime, with 3% having recurrent episodes2. Vasovagal syncope (VVS) is an exaggerated tendency towards the common faint that accounts for up to 29% of syncope3 and affects all age groups. VVS is characterised by profound hypotension with or without bradycardia. Those with VVS are at risk of injury during episodes and the long term implications of recurrent episodes of hypotension are unclear1. The underlying pathophysiology of VVS is uncertain and current treatments involve salt and fluid replacement and maintenance of blood pressure using mineralocorticoids or alpha agonists1. These treatments are largely symptomatic and may be associated with side effects that make their use in younger age groups inappropriate4. VVS can generally be differentiated from other causes of syncope through clinical evaluation. A definitive diagnosis of VVS is made by Head-up Tilt Table (HUT) test with the diagnosis of VVS being confirmed when a patient develops hypotension and/or bradycardia in association with syncopal or presyncopal symptoms5. One of the main methodological threats to current research into VVS is the appropriate measurement of VVS. A HUT is the most sensitive tool to diagnose VVS5. The majority of studies however have recruited participants diagnosed by medical evaluation and symptom pattern recognition only6,7,8,9,10. Although this method of diagnosis has some degree of reliability and validity, it is not as reliable as a diagnosis made by HUT. There can be a wide range of reported illness and disability associated with the same level of disease11. The experience of VVS is at best inconvenient, and may be perceived as threatening and disabling. In this review we will consider the evidence that psychological factors play a role in the development and maintenance of the symptoms of syncope, and more specifically vasovagal syncope, and whether psychological interventions might impact upon the manifestation and consequences of these symptoms. Research into the psychological factors in syncope has mainly involved groups of participants who have syncope of mixed origin. There are very few studies that have focussed exclusively on VVS as a separate condition. Further, it is also important to appreciate that there are no measures specific to VVS and that in many studies the diagnosis of VVS is by clinical evaluation rather than by a positive diagnostic test, raising the question that all that is syncopemay not be vasovagal in origin.