Vasovagal faint (typical vasovagal syncope)
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Typical vasovagal syncope, normal ECG
In the practice
- 12-lead ECG; blood pressure lying then standing; cardiac and neurological examination
- No routine laboratory tests: tests only depending on the context
Depending on the context
- FBC (if anaemia or bleeding suspected)if needednon-French guidelineVisible or suspected bleeding, suspected anaemia: NICE has haemoglobin measured in this case, ESC haemoglobin or haematocrit if haemorrhage is suspected [2,3].
- Serum electrolytesif neededDiuretic treatment or other drug involved, dehydration: HAS accepts routine tests when a clinical abnormality, a comorbidity or the treatment justifies them [1,2].
- Serum creatinineif neededDiuretic treatment or other drug involved, dehydration: HAS accepts routine tests when a clinical abnormality, a comorbidity or the treatment justifies them [1,2].
- Plasma glucose (if treated diabetes or suspected hypoglycaemia)if needednon-French guidelineTreated diabetes, suspected hypoglycaemia: NICE has blood glucose checked in this case [2]. In the practice, capillary blood glucose is usually enough.
Do not order
- “Screening” laboratory tests (FBC, serum electrolytes, creatinine, plasma glucose) for typical vasovagal syncope: only exceptionally useful, only if a clinical abnormality, a comorbidity or the treatment justifies them [1]
- Tilt test when the diagnosis of vasovagal syncope is made at initial assessment: NICE recommends not offering it [2]
- Routine EEG in the investigation of brief loss of consciousness: not recommended by NICE [2]
Unexplained or atypical syncope (other than typical vasovagal syncope)
In the practice
- 12-lead ECG (and comparison with previous ECGs); blood pressure lying then standing; auscultation of the heart and supra-aortic vessels; hydration status.
Laboratory tests depending on the context (none is routine)
- FBC (if anaemia or bleeding suspected)if needednon-French guidelineSuspected anaemia or bleeding: NICE has haemoglobin measured in this case [2].
- Serum electrolytesif neededClinical abnormality, comorbidity or treatment that justifies them (diuretic, dehydration) [1].
- Serum creatinineif neededClinical abnormality, comorbidity or treatment that justifies them (diuretic, dehydration) [1].
- Plasma glucose (if treated diabetes or suspected hypoglycaemia)if needednon-French guidelineSuspected hypoglycaemia in a person with treated diabetes: NICE has blood glucose checked [2].
Also consider
Do not order
- Tilt test before ambulatory ECG recording in unexplained syncope: NICE recommends not offering it [2].
Sources (7)
- Haute Autorité de santé. Pertes de connaissance brèves de l'adulte : prise en charge diagnostique et thérapeutique des syncopes. Recommandations professionnelles, mai 2008.
- National Institute for Health and Care Excellence. Transient loss of consciousness ('blackouts') in over 16s. Clinical guideline CG109, août 2010, dernière mise à jour le 21 novembre 2023.
- Brignole M, Moya A, de Lange FJ, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J. 2018;39(21):1883-948.
- Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope. J Am Coll Cardiol. 2017;70(5):e39-e110.
- Runser LA, Gauer RL, Houser A. Syncope: evaluation and differential diagnosis. Am Fam Physician. 2017;95(5):303-312B.
- Deutsches Ärzteblatt. Neurologische Fachgesellschaft stellt neue Leitlinie zu Synkopen vor. 6 mai 2020 (résumé de la recommandation S1 « Synkopen » de la Deutsche Gesellschaft für Neurologie).
- Santé publique France. Quels sont les signes d'une intoxication au monoxyde de carbone ? Dossier thématique, consulté le 12 octobre 2026.