vasovagal reaction (fainting)
Jump to navigation
Jump to search
Introduction
A form of syncope.
Etiology
- precipitating factors
- fear
- pain
- emotional stress
- prolonged standing
- predisposing factors
Epidemiology
- occurs less frequently in the elderly[6]
Pathology
- orthostatic stress
- pooling of blood in the lower extremities (500-800 mL)
- compensatory increased adrenergic tone
- parasympathetic reflex
- decreased preload results in stimulation of mechano-receptors in the left ventricular wall by vigorous cardiac contraction against a relatively empty ventricle
- signals sent to midbrain from left ventricular mechano-receptors resulting in withdrawal of peripheral sympathetic tone & augmentation of vagal tone
- sudden peripheral vasodilatation, especially in skeletal muscle without compensatory rise in cardiac output
- decrease in reflex peripheral vasoconstriction[11]
- drop in blood pressure
- bradycardia may occur
Physical examination
- orthostatic blood pressure examination
Clinical manifestations
- prodrome
- generally occurs when standing, possibly sitting
- recovery
- a few clonic jerks or urinary incontinence may be noted
Diagnostic procedures
- electrocardiography (all)[3]
- tilt table testing for multiple episodes of syncope suspected to be of vasovagal origin[3]
Management
- place patient in supine position or with head in dependent position (below heart, i.e. between legs)
- prophylaxis:
- drinking 16 oz (1 pint) of water prior to risky setting
- compression stockings reduce pooling of blood in the lower extremities[11]
- first line
- muscle-tensing exercises when a prodrome is sensed[5][7]
- hand-clasping with interlocking fingers while pulling the elbows in opposite directions
- squeezing a ball or other object
- standing leg cross-over firmly pushing in thighs while tensing abdominal muscles
- counterpressure maneuvers include leg crossing, limb &/or abdominal contraction & squatting
- first line
- pharmacotherapy
- see neurocardiogenic vasopressor dysfunction
- fludrocortisone may benefit some patients[10]
- midodrine 2.5 mg BID - 10 mg TID may be effective for recurrent vasovagal syncope
- failure of first line therapy[12]
- without hypertension, heart failure, or urinary retention[12]
- beta-blockers for recurrent vasovagal syncope in patients > 42 years
- ablation of ganglionated plexus in the left atrium & right atrium may reduce recurrence of vasovagal syncope[13]
- prognosis:
- reassurance for young patients
- worse for elderly
- 16% have major morbidity/mortality within 6 months
More general terms
Additional terms
References
- ↑ Guide to Physical Examination & History Taking, 6th edition, Bates B, JB Lippincott, Philadelphia, 1995, pg 90-91
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 649
- ↑ 3.0 3.1 3.2 Medical Knowledge Self Assessment Program (MKSAP) 11, 17, 19. American College of Physicians, Philadelphia 1998, 2015, 2022
- ↑ Journal Watch 24(2):15, 2004 Lu CC, Diedrich A, Tung CS et al Water ingestion as prophylaxis against syncope. Circulation 108:2660, 2003 PMID: https://www.ncbi.nlm.nih.gov/pubmed/14623807
- ↑ 5.0 5.1 Internal Medicine News 39(8): April 15, 2006
- ↑ 6.0 6.1 Tan MP, Parry SW. Vasovagal syncope in the older patient. J Am Coll Cardiol. 2008 Feb 12;51(6):599-606. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/18261677
Duncan GW, Tan MP, Newton JL, Reeve P, Parry SW. Vasovagal syncope in the older person: differences in presentation between older and younger patients. Age Ageing. 2010 Jul;39(4):465-70. Epub 2010 May 5. PMID: https://www.ncbi.nlm.nih.gov/pubmed/20444805 - ↑ 7.0 7.1 van Dijk N, Quartieri F, Blanc JJ et al Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope: the Physical Counterpressure Manoeuvres Trial (PC-Trial). J Am Coll Cardiol. 2006 Oct 17;48(8):1652-7. Epub 2006 Sep 26. PMID: https://www.ncbi.nlm.nih.gov/pubmed/17045903
- ↑ Aydin MA, Salukhe TV, Wilke I, Willems S. Management and therapy of vasovagal syncope: A review. World J Cardiol. 2010 Oct 26;2(10):308-15. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21160608
- ↑ Forleo C, Guida P, Iacoviello M et al Head-up tilt testing for diagnosing vasovagal syncope: a meta-analysis. Int J Cardiol. 2013 Sep 20;168(1):27-35. PMID: https://www.ncbi.nlm.nih.gov/pubmed/23041006
- ↑ 10.0 10.1 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. <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/27364043 <Internet> 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 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/27364044 <Internet> http://content.onlinejacc.org/article.aspx?articleid=2530082 - ↑ 11.0 11.1 11.2 Geriatric Review Syllabus, 10th edition (GRS10) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2019
- ↑ 12.0 12.1 12.2 Sheldon R, Faris P, Tang A et al. Midodrine for the prevention of vasovagal syncope: A randomized clinical trial. Ann Intern Med 2021 Aug 3; [e-pub]. PMID: https://www.ncbi.nlm.nih.gov/pubmed/34339231 https://www.acpjournals.org/doi/10.7326/M20-5415
Brignole M. Establishing the efficacy of midodrine to prevent vasovagal syncope. Ann Intern Med 2021 Aug 3; [e-pub]. PMID: https://www.ncbi.nlm.nih.gov/pubmed/34339220 https://www.acpjournals.org/doi/10.7326/M21-2859 - ↑ 13.0 13.1 Piotrowski R et al. Cardioneuroablation for reflex syncope: Efficacy and effects on autonomic cardiac regulation - A prospective randomized trial. JACC Clin Electrophysiol 2022 Aug 28; [e-pub]. PMID: https://www.ncbi.nlm.nih.gov/pubmed/36114133 https://www.sciencedirect.com/science/article/abs/pii/S2405500X22006806
- ↑ Grubb BP Neurocardiogenic Syncope. N Engl J Med 2005;352:1004-10. PMID: https://www.ncbi.nlm.nih.gov/pubmed/15758011 https://www.nejm.org/doi/pdf/10.1056/NEJMcp042601