Classical Vasovagal Syncope
Vasovagal syncope triggered by fear, pain, or emotional stress is termed "classical VVS" (classical vasovagal syncope) according to the European Society of Cardiology guidelines. 1
Terminology and Classification
The 2018 ESC guidelines specifically designate syncope occurring in response to "fear, pain, instrumentation" as "Classical VVS" to distinguish it from other subtypes of vasovagal syncope. 1
Key Distinguishing Features:
Classical VVS is primarily triggered by emotional distress (fear, anxiety, blood phobia) or pain, as opposed to orthostatic stress alone 1, 2
This differs from orthostatic VVS, which occurs predominantly during prolonged standing without a specific emotional trigger 1
It is also distinct from situational syncope, which requires specific physical triggers like coughing, micturition, or defecation 1, 3, 2
Pathophysiological Mechanism
Classical VVS represents an inappropriate autonomic reflex where emotional or pain stimuli trigger:
- Excessive vasodilation throughout the body, causing blood pooling and systemic hypotension 4, 2
- Reflex bradycardia (slowing of heart rate), further reducing cardiac output 4, 5
- The combination results in cerebral hypoperfusion and loss of consciousness 4, 2, 5
Clinical Recognition
Prodromal symptoms that typically precede classical VVS include:
- Nausea and sweating (diaphoresis) 1, 4
- Pallor 1, 4
- Lightheadedness and visual changes 4, 2
- These autonomic activation symptoms distinguish it from cardiac syncope, which often lacks a prodrome 2
Common Pitfall:
Do not confuse classical VVS with cardioinhibitory VVS occurring in the supine position through pain or fear—while both involve emotional triggers, supine syncope suggests a more profound cardioinhibitory response and warrants closer cardiac evaluation. 1