neurocardiogenic vasopressor dysfunction; neurally-mediated syncope; reflex syncope (NVD)

Classification

• vasovagal reaction
• carotid sinus syncope
• situational syncope
  • postmicturition syncope
  • cough syncope
  • heat syncope
  • postprandial syncope
  • postdefecation syncope
• other: vasovagal-type reactions in cardiac transplant patients with denervated hearts

Etiology

• prolonged standing
• orthostatic hypotension
  • hypovolemia
  • pharmaceutical agents
  • autonomic dysfunction
• increased adrenergic or emotional state
• pharmaceutical agents
  • vasodilators
  • diuretics
  • nitrates

Epidemiology

• accounts for the majority of syncopal episodes in the general population

Pathology

• usually seen in patients with normal left ventricular function in the absence of structural heart disease
• generally benign condition

Clinical manifestations

• lightheadedness, wooziness
• nausea, warmth, diaphoresis

Diagnostic procedures

• baseline electrocardiogram (routine)
• not routine
  • echocardiogram to assess structural heart disease
  • event recorder better than HOLTER for capturing rhythm during syncopal event
  • tilt-table testing for patients with recurrent syncope & absence of structural heart disease
    • useful in patients with LVEF > 40% in whom NVD is suspected, in which delayed orthostatic hypotension develops over 15-45 minutes

Management

• general measures
  • adequate hydration
  • use caution with changes in postural position
  • compression stockings may reduce pooling of blood in lower extremities
  • hospitalization generally unnecessary
  • reassurance for young patients
• pharmacologic therapy
  • beta-blockers (cardioselective {beta-1} best); of no benefit
  • disopyramide
  • theophylline
  • anticholinergic agents
  • serotonin reuptake inhibitors
  • fludrocortisone may benefit some patients

More general terms

• syncope

More specific terms

• carotid sinus syndrome; carotid sinus hypersensitivity; carotid sinus syncope
• vasovagal reaction (fainting)