Emergency Care Institute – Clinical tools

Syncope

Published: October 2020. Next review: 2026. Printed on 15 Jan 2025.

On this page

Syncope is defined as a rapid onset of loss of consciousness of short duration as a result of global cerebral hypoperfusion with loss of postural tone, which is followed by spontaneous and complete recovery.1

The goals of assessment in the emergency department are to:

  • recognise life threatening conditions
  • determine if it is syncope or not
  • risk stratify into high risk or low risk and manage accordingly.

Life threatening conditions with syncope include pulmonary embolus, cardiac arrythmia, thoracic aortic dissection, ruptured abdominal aorta, ectopic pregnancy and subarachnoid haemorrhage.

Useful tools

Classification

  1. Neurally mediated (reflex)
  2. Orthostatic hypotension
  3. Cardiac

Access a clear and detailed classification list from the European Society of Cardiology.1

All patients presenting with syncope require a careful history, physical examination (including orthostatic BP measurements), blood glucose and 12-lead electrocardiogram (ECG). A normal serum troponin T has a poor negative predictive value for adverse cardiac outcomes following syncope. View the abstract of the 2005 Hing and Harris study.

Additional examinations (carotid sinus massage, echocardiogram, ECG monitoring or orthostatic challenge), blood tests and imaging are guided by clinical context and disposition.

Risk stratification and management

High-risk episodes

  • High-risk criteria includes severe structural or coronary artery disease, clinical or ECG features suggesting arrhythmic syncope (syncope on exertion or supine, palpitations at the time of syncope, family history of sudden cardiac death or non-sustained ventricular tachycardia) and important co-morbidities (including anaemia and electrolyte disturbance).
  • Patients with high-risk criteria require prompt hospitalisation or intensive evaluation.
  • Access a clear risk stratification list from the European Society of Cardiology.1

Low-risk episodes

  • Single or rare episodes: requires no further investigations and the patient may be discharged home with general practitioner follow-up.
  • Recurrent episodes: can have delayed further investigations. Patients may be discharged depending on circumstances and following senior emergency department review.

Syncope rules

Other risk stratification rules may assist in identifying patients at risk. Examples of these are: San Francisco Syncope rule2, OESIL score3, EGSYS score4 and a study by Martin et al5. The common findings are that abnormal ECG, increased age and history of heart disease imply a worse prognosis at 1 year follow-up.

More information can be found in the further reading section below.

Treatment

Most patients who present with syncope return to normal by the time you assess them.

The goals of treatment are to:

  • prolong survival
  • limit physical injuries
  • prevent recurrences.

Disposition can at times be challenging and particularly in the low-risk recurrent group, despite this group representing patents who may have unknown risk characteristics which are yet to be documented or defined. Inpatient teams are often reluctant to admit them as ‘subspecialisation’ has difficulties with the unknown. These patients  should be reviewed by your senior emergency department doctor prior to discharge (if that is the decision) and a defined follow up should be clearly documented and communicated to the patient and their general practitioner.

Further reading

  • Brignole M, Hamdan M. New concepts in the assessment of syncope. J Am Coll Cardiol. 1 May 2012;59(18):1583-91. DOI: 10.1016/j.jacc.2011.11.056
  • Morag R. Syncope. USA: Medscape; Jun 2012 [updated 13 Jan 2017; cited 18 June 2024].
  • Parry S, Tan M. An approach to the evaluation and management of syncope in
    adults. BMJ. 2010;340:c880. DOI: 10.1136/bmj.c880
  • Strickberger SA, Benson DW, Biaggioni I, et al. AHA/ACCF scientific statement on the evaluation of syncope: from the American Heart Association Councils on Clinical Cardiology, Cardiovascular Nursing, Cardiovascular Disease in the Young, and Stroke, and the Quality of Care and Outcomes Research Interdisciplinary Working Group; and the American College of  Cardiology Foundation in Collaboration With the Heart Rhythm Society. Circulation. 2006; 113: 316–327. DOI: 10.1161/CIRCULATIONAHA.105.170274

References

  1. Moya A, Sutton R. Guidelines for the diagnosis and management of syncope (version 2009): the task force for the diagnosis and management of syncope of the European Society of Cardiology. Eur Heart J 2009; 30: 2631-71. DOI: 10.1093/eurheartj/ehp298
  2. Quinn J, McDermott D, Stiell I, et al. Prospective validation of the San Francisco Syncope Rule to predict patients with serious outcomes. Ann Emerg Med. 2006; 47: 448-454. DOI: 10.1016/j.annemergmed.2005.11.019
  3. Colivicchi F, Ammirati F, Melina D, et al. Development and prospective validation of a risk stratification system for patients with syncope in the emergency department: the OESIL risk score Eur Heart J (2003) 24 (9): 811-819. DOI:10.1016/S0195-668X(02)00827-8
  4. Del Rosso A, Ungar A, Maggi R, et al. Clinical predictors of cardiac syncope at initial evaluation in patients referred urgently to a general hospital: the EGSYS score. Heart. 2008 Dec;94(12):1620-6. DOI: 10.1136/hrt.2008.143123. Epub 2008 Jun 2
  5. Martin TP, Hanusa BH, Kapoor WN. Risk stratification of patients with syncope. Ann Emerg Med 1997;29 (4):459-466. DOI: 10.1016/S0196-0644(97)70217-8

Accessed from the Emergency Care Institute website at https://aci.health.nsw.gov.au/networks/eci/clinical/tools/syncope

Back to top