Neurally mediated reflex syncope

Neurally mediated reflex syncope (NMRS) refers to a group of related conditions or scenarios in which symptomatic hypotension occurs as a result of neural reflex vasodilation and/or bradycardia.

Vasovagal syncope (VS) refers to a particular type of NMRS also known as the common faint.

VS has many manifestations and is generally considered to encompass faints triggered by emotional upset, fear, and pain, as well as those occurring in less well-defined circumstances.

Patient education is the foundation of treatment for most NMRS syndromes, including VS.

Patients must be informed that, although reflex faints are almost never life-threatening, they tend to recur (often in clusters), and injury can result if preventive measures are not taken seriously.

Strategies for reducing syncope recurrences in the long term comprise 1) physical techniques to improve orthostatic tolerance, 2) pharmacological interventions to prevent depletion of intravascular volume and/or enhance arterial and venous tone, 3) cardiac pacing to avert bradycardia.

Syncope is a syndrome characterised by a relatively sudden, temporary, and self-terminating loss of consciousness, associated with the inability to maintain postural tone, with rapid and spontaneous recovery.[1]Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: a report of the American College of Cardiology/American Heart Association Task Force on clinical practice guidelines, and the Heart Rhythm Society. Heart Rhythm. 2017 Aug;14(8):e155-e217. https://circ.ahajournals.org/content/early/2017/03/09/CIR.0000000000000499 http://www.ncbi.nlm.nih.gov/pubmed/28286247?tool=bestpractice.com The causes vary widely from patient to patient, but they have a common underlying pathophysiology.[2]Brignole M, Moya A, de Lange FJ, et al; ESC Scientific Document Group. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J. 2018 Jun 1;39(21):1883-948. https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehy037/4939241 http://www.ncbi.nlm.nih.gov/pubmed/29562304?tool=bestpractice.com [3]Blanc J-J, Benditt DG. Syncope: definition, classification, and multiple potential causes. In: Benditt DG, Blanc J-J, Brignole M, et al, eds. The evaluation and treatment of syncope: a handbook for clinical practice. Elmsford, NY: Futura/Blackwell; 2003:3-10. The transient loss of consciousness with syncope is the result of a temporary inadequacy of cerebral nutrient flow, most often triggered by a fall in systemic arterial pressure below the minimum needed to sustain cerebral blood flow. Neurally mediated reflex syncope (NMRS) refers to a group of related conditions or scenarios in which symptomatic hypotension occurs as a result of neural reflex vasodilation and/or bradycardia.[1]Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: a report of the American College of Cardiology/American Heart Association Task Force on clinical practice guidelines, and the Heart Rhythm Society. Heart Rhythm. 2017 Aug;14(8):e155-e217. https://circ.ahajournals.org/content/early/2017/03/09/CIR.0000000000000499 http://www.ncbi.nlm.nih.gov/pubmed/28286247?tool=bestpractice.com Vasovagal syncope (VS) refers to a particular type of NMRS also known as the common faint.