MedSchool: Ace Your OSCEsThe Medical Company
GET - On the App Store
Cardio History

Presyncope / Syncope



  • Presyncope is a feeling of lightheadedness or of being about to ‘faint'. Syncope is the transient loss of consciousness, or the act of ‘fainting'.
  • Often patients present with ‘dizziness', which may refer to lightheadedness, vertigo, motor instability or anxiety. It is important to gain further history and differentiate between these symptoms.


    • Causes of Presyncope / Syncope

    • Neurally Mediated

    • Vasovagal syncope
    • Situational - coughing, micturition, defaecation, playing brass instruments, valsalva
    • Carotid sinus syndrome - hypersensitivity of the carotid sinus
    • Cardiac

    • Arrhythmia - sick sinus, AV block, SVT, AF, VT
    • Structural - aortic stenosis, acute coronary syndrome, obstructive cardiomyopathy
    • Orthostatic

    • Volume loss - dehydration, haemorrhage
    • Primary autonomic failure - Parkinson’s, multisystem atrophy, MS
    • Secondary autonomic failure - diabetic neuropathy, amyloidosis, HIV neuropathy, CIPD
    • Drugs - antihypertensives, vasodilators, diuretics, antidepressants
    • Cerebrovascular

    • Stroke / TIA
    • Vascular steal syndrome
    • Other

    • Pulmonary embolism

Differential Diagnosis

    • Differential Diagnosis for Dizziness

    • Spinning Sensation - that the patient or the room is spinningVertigo, i.e. vestibular pathology
    • Lightheadedness - a feeling of nearly faintingPresyncope
    • Dysequilibrium - a feeling of poor balanceGait disorder
    • Overwhelmed sensation - a disconnection from the worldAnxiety
    • Differential Diagnosis for Loss of Consciousness

    • Intracranial

    • Haemorrhage - intracerebral, subarachnoid, subdural, extradural
    • Infarction
    • Infection - meningitis, encephalitis, abscess
    • Tumour - mass effect, cerebral oedema
    • Post ictal state
    • Head trauma - vascular, hypoxia, cerebral oedema, parenchymal injury
    • Psychiatric - conversion, depression, catatonia
    • Extracranial

    • Cardiovascular - shock, hypertension
    • Infection - septicaemia
    • Metabolic - hypo/hyperosmolar states, hypo/hyperglycaemia, hypothyroidism, hypopituitarism, electrolyte abnormality, hypoxia, hepatic failure, renal failure
    • Endocrine - adrenal crisis, myxoedema coma
    • Drugs / toxins - sedatives, analgesics, alcohol
    • Physical injury - hyper / hypothermia, electrocution

History of Presenting Complaint

    • Trigger

      Whether there was anything that may have precipitated the presyncope or syncope.
    • Standing after lying / sittingSuggestive of vasovagal syncope or orthostatic hypotension
    • NOT triggered by postural changeSuggestive of arrhythmia
    • Pain or emotional stressVasovagal syncope
    • Venesection or seeing bloodVasovagal syncope
    • EatingSituational (postprandial) syncope
    • Micturition or defaecationSituational (micturition / defaecation) syncope
    • Paroxysm of coughSituational syncope
    • Weightlifting or playing a brass instrumentSituational (weightlifter’s / trumpet player’s) syncope
    • Head rotation or wearing a tight collarSuggestive of carotid sinus syndrome
    • ShavingSuggestive of carotid sinus syndrome
    • ExerciseSuggestive of arrhythmia or cardiac structural disease
    • Arm exercisesSuggestive of vascular steal syndrome
    • Before the Episode

      Whether the patient had any symptoms just prior to the episode of syncope.
    • LightheadednessSuggestive of syncope, rather than seizure
    • Nausea, flushing and diaphoresisSuggestive of vasovagal syncope
    • Chest pain +/- diaphoresisSuggestive of acute coronary syndrome or pulmonary embolism
    • Arm / leg weakness or facial droopSuggestive of stroke / TIA
    • Shortness of breathMay represent heart failure in the setting of aortic stenosis
    • PalpitationsSuggestive of arrhythmia
    • Visual changes or altered sense of smellSuggestive of preictal state
    • During the Episode

    • Loss of consciousness for a few secondsMore suggestive of syncope than seizure
    • Short episode of myoclonic movementMore suggestive of vasovagal than seizure
    • Tonic-clonic movementsSuggestive of seizure rather than syncope
    • Tongue biting or urinary incontinenceSuggestive of seizure rather than syncope
    • After the Episode

    • Nausea and vomitingSuggestive of vasovagal syncope
    • Short period of disorientationMay occur post vasovagal
    • ConfusionSuggestive of post-ictal period
    • Arm / leg weakness or facial droopSuggestive of stroke / TIA
    • Timing

    • The frequency and duration of these episodes.
    • Associated Symptoms

      Whether the patient has been unwell recently.
    • Vomiting or diarrhoeaSuggestive of orthostatic hypotension due to volume loss
    • PR bleeding, malaena or haematemesisSuggestive of orthostatic hypotension due to volume loss
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Sign Up Now


 Abbott AV. Diagnostic approach to palpitations. Am Fam Physician. 2005 Feb 15;71(4):743-50. Arthur W, Kaye GC. The pathophysiology of common causes of syncope. Postgraduate medical journal. 2000 Dec 1;76(902):750-3. Benditt DG. Neurally mediated syncopal syndromes: pathophysiological concepts and clinical evaluation. Pacing and clinical electrophysiology. 1997 Feb 1;20(2):572-84. Cayley J,William E. Chest pain--tools to improve your in-office evaluation. J Fam Pract. 2014;63:246.
Constant J. The diagnosis of nonanginal chest pain.  Keio J Med. 1990;39:187-192.
 Cotter L. History and Examination of the Cardiovascular System. Medicine. 2010; 38(7): 344-347. Eriksson B, Vuorisalo D, Sylven C. Diagnostic potential of chest pain characteristics in coronary care.  J Intern Med. 1994;235:473-478 Faselis C, Doumas M, Papademetriou V. Common secondary causes of resistant hypertension and rational for treatment. International journal of hypertension. 2011 Mar 2;2011.
Kass S. Pleurisy. Am Fam Physician. 2007;75:1357.
 Khot UN, Khot MB, Bajzer CT, Sapp SK, Ohman EM, Brener SJ, Ellis SG, Lincoff AM, Topol EJ. Prevalence of conventional risk factors in patients with coronary heart disease. Jama. 2003 Aug 20;290(7):898-904. Kim EJ, Kim BH, Seo HS, Lee YJ, Kim HH, Son HH, Choi MH. Cholesterol-induced non-alcoholic fatty liver disease and atherosclerosis aggravated by systemic inflammation. PloS one. 2014 Jun 5;9(6):e97841. Mak SM, Strickland N, Gopalan D. Complications of pulmonary hypertension: a pictorial review. The British journal of radiology. 2017 Feb;90(1070):20160745.
Miller TH, Kruse JE. Evaluation of syncope. Am Fam Physician. 2005 Oct 15;72(8):1492-500.
Mosterd A, Hoes AW. Clinical epidemiology of heart failure. Heart. 2007 Sep 1;93(9):1137-46.
 National Vascular Disease Prevention Alliance. Guidelines for the management of absolute cardiovascular disease risk. 2012.
Onusko E. Diagnosing secondary hypertension. American family physician. 2003 Jan;67(1):67-74.
 Payne RA. Cardiovascular Risk. British Journal of Clinical Pharmacology. 2012; 74(3): 396-410. Petersen P. Thromboembolic complications in atrial fibrillation. Stroke. 1990 Jan;21(1):4-13.
Schoenkerman A, Goldschlager N. Chest Pain: Does This Patient Have Cardiac Ischaemia? Consultant. 2013; 53(8): 556-560.
 Simonneau G, Gatzoulis MA, Adatia I, Celermajer D, Denton C, Ghofrani A, Sanchez MA, Kumar RK, Landzberg M, Machado RF, Olschewski H. Updated clinical classification of pulmonary hypertension. Journal of the American College of Cardiology. 2013 Dec 24;62(25 Supplement):D34-41. Susanto M. Dizziness: if not vertigo could it be cardiac disease?. Australian family physician. 2014 May;43(5):264. Swap CJ, Nagurney JT. Value and Limitations of Chest Pain History in the Evaluation of Patients With Suspected Acute Coronary Syndromes. JAMA. 2005;294:2623-2629. Vodnala D, Rubenfire M, Brook RD. Secondary causes of dyslipidemia. The American journal of cardiology. 2012 Sep 15;110(6):823-5. Wahls SA. Causes and evaluation of chronic dyspnea. American family physician. 2012 Jul 15;86(2). Watson RD, Gibbs CR, Lip GY. ABC of heart failure: clinical features and complications. BMJ: British Medical Journal. 2000 Jan 22;320(7229):236. Weber BE, Kapoor WN. Evaluation and outcomes of patients with palpitations. The American journal of medicine. 1996 Feb 29;100(2):138-48.
Wexler RK, Pleister A, Raman S. Outpatient approach to palpitations. heart disease. 2011 Jul 1;100:6.
 Yuan G, Al-Shali KZ, Hegele RA. Hypertriglyceridemia: its etiology, effects and treatment. Cmaj. 2007 Apr 10;176(8):1113-20. Zimetbaum P, Josephson ME. Evaluation of patients with palpitations. New England Journal of Medicine. 1998 May 7;338(19):1369-73.