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

Classification: 1) vasovagal reaction 2) carotid sinus syncope 3) situational syncope a) postmicturition syncope b) cough syncope c) heat syncope d) postprandial syncope e) postdefecation syncope 7) other: vasovagal-type reactions in cardiac transplant patients with denervated hearts Etiology: - prolonged standing - orthostatic hypotension a) hypovolemia b) pharmaceutical agents c) autonomic dysfunction - increased adrenergic or emotional state - pharmaceutical agents a) vasodilators b) diuretics c) 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 [3] Clinical manifestations: - lightheadedness, wooziness - nausea, warmth, diaphoresis Special laboratory: - 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: 1) general measures a) adequate hydration b) use caution with changes in postural position c) compression stockings may reduce pooling of blood in lower extremities [6] d) hospitalization generally unnecessary [3] e) reassurance for young patients 2) pharmacologic therapy a) beta-blockers (cardioselective {beta-1} best) [1,3]; of no benefit [2] b) disopyramide c) theophylline d) anticholinergic agents e) serotonin reuptake inhibitors f) fludrocortisone may benefit some patients [5]

Specific

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

General

syncope

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 204
  2. Sheldon R et al, Prevention of Syncope Trial (POST): A randomized, placebo- controlled study of metoprolol in the prevention of vasovagal syncope Circulation 2006; 113:1164 PMID: 16505178
  3. Medical Knowledge Self Assessment Program (MKSAP) 14, 16. American College of Physicians, Philadelphia 2006, 2012
  4. Duplyakov D, Golovina G, Garkina S, Lyukshina N. Is it possible to accurately differentiate neurocardiogenic syncope from epilepsy? Cardiol J. 2010;17(4):420-7. Review. PMID: 20690104
  5. Sheldon R, Raj SR, Rose MS et al Fludrocortisone for the Prevention of Vasovagal Syncope. A Randomized, Placebo-Controlled Trial. J Am Coll Cardiol. 2016;68(1):1-9. PMID: 27364043 http://content.onlinejacc.org/article.aspx?articleid=2530086 - Brignole M Finally, a Drug Proves to Be Effective Against Vasovagal Syncope! But Not in All Patients. J Am Coll Cardiol. 2016;68(1):10-12 PMID: 27364044 http://content.onlinejacc.org/article.aspx?articleid=2530082
  6. Geriatric Review Syllabus, 10th edition (GRS10) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2019