Vasovagal syncope

Different types of vasovagal syncope

• Young patients
• Old patients
• Post-exercise Syncope
• Blood phobia
• Blood donation
• Vasovagal syncope during sleep

Triggers for Vasovagal Syncope

Vasovagal syncope can occur after exposure of a lot of different triggers. Recognised triggers for vasovagal syncope are prolonged orthostatic stress, blood drawing, medical instrumentation and psychological stressors.

Psychological stressors

Psychological stressors include:

• Stirring emotional news or witnessing a distressing accident [1],[2]
• Unexpected pain or threat [1],[3]
• Unpleasant smells may trigger vasovagal syncope [4],[5]
• During blood drawing,
• Vaccination [6]
• Instrumentation, pain of the procedure may contribute to vasovagal syncope
• Sharp pain is reported to be an important factor during arterial blood sampling [7].
• Blood phobia: However, in a patient with blood phobia just thinking or talking about blood drawing may elicit a common faint [8]

Vasovagal syncope in airliners

Vasovagal episodes are the most common in-flight medical events, and may affect patients of all ages [9]. The following may all predispose vasovagal faints during air travel [10]:

• Prolonged motionless sitting
• The use of alcohol
• Anxiety
• Mild hypoxia during air travel

Cabin pressure in commercial aircraft is usually adjusted to the equivalent of an altitude of 1500 to 2500 m above sea level. It appears that hypoxic syncope results from the super-imposed vasodilator effects of hypoxia on the cardiovascular system [11].

Treatment

Patients, who otherwise never experienced a (severe) vasovagal episode may suffer from convulsive syncope during air travel [12]. These patients should be advised to have:

• A high salt intake in the days prior to travelling by plane
• Reduce anti-hypertensive medication –if feasible-
• And drink non-alcoholic beverages galore during the trip.

Especially during long flights (> 2 hours) they should perform in-chair muscle tensing and relaxing exercise and have a regular walk through the isle. In recurrent cases midodrine prior to flying or supportive stockings can be considered.

References

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2. Engel GL, Romano J, & McLin TR (1944). Vasodepressor and carotid sinus syncope - clinical, eletroencephalographic and electrocardiographic observations. Arch Intern Med 74, 100-119.

3. GREENFIELD AD (1951). An emotional faint. Lancet 1, 1302-1303.

4. Engel GL & Romano J (1947). Studies of Syncope: IV. Biologic interpretation of vasodepressor syncope. Psychosom Med 9, 288-294.

7. Rushmer, R.F. Circulatory collapse following mechanical stimulation of arteries. Am. J. Physiol. 1944;141:722.

20. Jardine DL, Krediet CT, Cortelli P, & Wieling W (2006b). Sleep syncope: clinical features and autonomic profiles. Clin Auton Res 16, 321-322.