Synonyms:
a.k.a. neurally mediated syncope a.k.a. Vasovagal syncope a.k.a. neurocardiogenic syncope a.k.a. vasodepressor syncope:
Clinical features:
Syncope after emotional stimulus
Syncope after Valsalva & Valsalva like: Cough, defaecation, Micturation, Deglutition, Hyperventilation
Syncope after hemodynamic/orthostatic stress e.g. prolonged standing
Preceded by autonomic activation:
Cold sweat: piloerection, sweating & pallor (vasoconstriction)
Nausea & epigastric discomfort (vagal activation)
Blurred vision (papillary vasoconstriction)
Preceded by lightheadedness & darkening of vision
Findings on Investigations:
+Head up tilt-table testing: positive
After tilt up there is a period of normal BP & HR. Then a sudden drop in BP & HR with recurrence of syncopal symptoms. In contrast in autonomic failure: After tilt up there is a progressive gradual drop in BP & HR.
+excluding heart disease +arrhythmia
Treatment:
Reassurance
Avoidance of precipitants
Increase fluid intake to >2L per day
Exercise training:
Training leg muscles
Stand against a wall for up to 40min, twice daily
Physical countermaneuvers:
- Leg crossing, squating
If recurrent neurocardiogenic syncope, consider:
- Salt loading
- Pacemakers are of no benefit [VPSII RCT]
- Beta blockers are of no benefit [Randomised crossover trial]