Guideline sources The following summarized guidelines for the evaluation and management of syncope are prepared by our editorial team based on guidelines from the European Society of Cardiology (ESC 2022; 2021; 2018; 2014), the American College of Radiology (ACR 2021), the American Heart Association (AHA/HRS/ACC 2019; 2018; 2017), and the Canadian Pediatric Cardiology Association (CPCA/CCS 2017). 1 2 3 4 5 6 7 8 9 Calculator Calculator Calculator Canadian syncope risk score Evaluation of Guidelines in Sync OESIL sco Guidelines 1. Screening and diagnosis https://web.pathway.md/diseases/recxj98tkWyAz2A9n 1/9 6/24/23, 3:14 PM Syncope Pathway Diagnostic criteria (situational syncope): Suspect situational reflex syncope with high probability in patients with syncope occurring during or immediately after specific triggers. B Confirm reflex syncope when syncope is reproduced immediately after exercise in the presence of severe hypotension. B Diagnostic criteria (vasovagal syncope): suspect vasovagal syncope with high probability in patients with syncope precipitated by pain, fear, or standing and associated with the typical progressive prodrome (such as pallor, sweating, and/or nausea). B Diagnostic criteria (carotid sinus syndrome): confirm carotid sinus syndrome when carotid sinus massage causes bradycardia (asystole) and/or hypotension reproducing spontaneous symptoms, and patients have clinical features compatible with a reflex mechanism of syncope. B Diagnostic criteria (orthostatic hypotension-induced syncope): confirm syncope due to orthostatic hypotension when syncope occurs while standing and there is concomitant significant orthostatic hypotension. B Suspect reflex syncope and orthostatic hypotension in the presence of features suggesting reflex syncope or orthostatic hypotension and the absence of features suggesting cardiac syncope. B Show 5 more Diagnostic criteria (cardiac syncope, arrhythmic): Suspect arrhythmic syncope with high probability in the presence of any of the following ECG findings: (Class : I, Level : C) persistent sinus bradycardia < 40 bpm or sinus pauses > 3 seconds in awake state and in the absence of physical training mobitz II second- and third-degree AV block alternating LBBB and RBBB VT or rapid paroxysmal supraVT non-sustained episodes of polymorphic VT and long or short QT interval pacemaker or implantable cardioverter defibrillator malfunction with cardiac pauses. B Show 3 more Diagnostic criteria (cardiac syncope, structural): suspect syncope due to structural cardiopulmonary disorders with high probability when syncope presents in patients with prolapsing atrial myxoma, LA ball thrombus, severe aortic stenosis, pulmonary embolus, or acute aortic dissection. B Show 2 more 2. Classification and risk stratification Risk assessment: As per ESC 2018 guidelines, consider using risk stratification scores for risk stratification in the emergency department. C As per ACC 2017 guidelines: https://web.pathway.md/diseases/recxj98tkWyAz2A9n 2/9 6/24/23, 3:14 PM Syncope Pathway Obtain evaluation of the cause and assessment for the short- and long-term morbidity and mortality risk of syncope. B Consider using risk stratification scores in the management of patients with syncope. C 3. Diagnostic investigations History and physical examination: As per ESC 2018 guidelines, elicit a careful history (concerning present and previous attacks, as well as eyewitness accounts, in person or through a telephone interview) and perform a physical examination (including supine and standing BP measurements) in patients with transient loss of consciousness of suspected syncopal nature. As per AHA 2017 guidelines, elicit a detailed history and perform a physical examination in patients with syncope. B Home video recording: encourage patients and their relatives to obtain home video recordings of spontaneous events. B Show 2 more Initial electrocardiogram: As per ESC 2018 guidelines, obtain an initial ECG in patients with transient loss of consciousness of suspected syncopal nature. As per AHA 2017 guidelines, obtain a resting 12-lead ECG as part of the initial evaluation of patients with syncope. B As per ESC 2014 guidelines, obtain a 12-lead ECG to identify the cause of symptoms in patients with unexplained syncope. B Cardiac monitoring, noninvasive techniques: As per ESC 2022 guidelines, consider obtaining ambulatory ECG monitoring to evaluate whether symptoms, including palpitations, presyncope, or syncope, are caused by ventricular arrhythmia. B As per ESC 2018 guidelines, obtain immediate in-hospital monitoring (in bed or by telemetry) in high-risk patients with syncope. B Show 2 more As per HRS/AHA/ACC 2017 guidelines: Consider obtaining any of the following external cardiac monitoring approaches, depending on the frequency and nature of syncope events, B in ambulatory patients with syncope of suspected arrhythmic etiology: holter monitoring transtelephonic monitoring external loop recorder patch recorder mobile cardiac outpatient telemetry. C https://web.pathway.md/diseases/recxj98tkWyAz2A9n 3/9 6/24/23, 3:14 PM Syncope Pathway Obtain continuous ECG monitoring in hospitalized patients admitted for syncope evaluation with suspected cardiac etiology. B As per ESC 2014 guidelines, obtain 48-hour ambulatory ECG monitoring to identify the cause of symptoms in patients with unexplained syncope. B Cardiac monitoring, implantable loop recorder: As per ESC 2021 guidelines, place an implantable loop recorder for long-term ambulatory monitoring in patients with infrequent (< 1 per month) unexplained syncope or other symptoms suspected to be caused by bradycardia, if the initial comprehensive evaluation is nondiagnostic. A As per ESC 2018 guidelines, place an implantable loop recorder in an early phase of evaluation in patients with recurrent syncope of uncertain origin, absence of high-risk criteria, and a high likelihood of recurrence within the battery life of the device. A Show 2 more As per HRS/ACC/AHA 2018 guidelines, consider placing an implanted cardiac monitor in patients with sporadic symptoms (including syncope) suspected to be related to ventricular arrhythmia. C As per HRS/AHA/ACC 2017 guidelines, consider placing an implantable cardiac monitor to evaluate selected ambulatory patients with syncope of suspected arrhythmic etiology. C Carotid sinus massage: As per ESC 2021 guidelines, perform carotid sinus massage in patients with syncope of unknown origin compatible with a reflex mechanism or with symptoms related to pressure/manipulation of the carotid sinus area, if carotid stenosis is ruled out. B As per ESC 2018 guidelines: Perform carotid sinus massage in > 40 years old patients with syncope of unknown origin compatible with a reflex mechanism. B Confirm carotid sinus syndrome when carotid sinus massage causes bradycardia (asystole) and/or hypotension reproducing spontaneous symptoms, and patients have clinical features compatible with a reflex mechanism of syncope. B Orthostatic challenge (active standing): obtain intermittent BP and HR measurement by sphygmomanometer while supine and during active standing for 3 minutes for the initial evaluation of syncope. B Show 7 more Orthostatic challenge, tilt testing: As per ESC 2021 guidelines, consider obtaining tilt testing in patients with suspected recurrent reflex syncope. C As per ESC 2018 guidelines, consider obtaining tilt testing in patients with suspected reflex syncope, orthostatic hypotension, postural orthostatic tachycardia syndrome, or psychogenic pseudosyncope. C Show 3 more https://web.pathway.md/diseases/recxj98tkWyAz2A9n 4/9 6/24/23, 3:14 PM Syncope Pathway As per HRS/AHA/ACC 2017 guidelines, consider obtaining tilt-table testing in patients with suspected vasovagal syncope if the diagnosis is unclear after initial evaluation. C Do not obtain tilt-table testing to predict response to medical treatments for vasovagal syncope. C Show 4 more Autonomic function tests (indications): consider referring selected patients with syncope and known or suspected neurodegenerative disease for autonomic evaluation. C Autonomic function tests (Valsalva maneuver): Consider performing the Valsalva maneuver to assess autonomic function in patients with suspected neurogenic orthostatic hypotension. C Consider performing the Valsalva maneuver to confirm the hypotensive tendency induced by some forms of situational syncope, such as coughing, brass instrument playing, singing, and weightlifting. C Autonomic function tests (deep-breathing test): obtain deep-breathing tests to assess autonomic function in patients with suspected neurogenic orthostatic hypotension. B Autonomic function tests (other tests): consider obtaining other autonomic function tests (such as the 30:15 ratio, cold pressure test, sustained hand grip test, and mental arithmetic test) to assess autonomic function in patients with suspected neurogenic orthostatic hypotension. C Ambulatory blood pressure monitoring: obtain ambulatory BP monitoring to detect nocturnal hypertension in patients with autonomic failure. B Show 2 more Cardiac imaging, echocardiography: As per ACR 2021 guidelines, obtain resting TTE as the initial imaging in patients with presyncope or syncope with clinical suspicion for cardiovascular etiology based on history, physical examination, and ECG findings. B As per ESC 2018 guidelines: Obtain echocardiography for diagnosis and risk stratification in patients with suspected structural heart disease. B Obtain 2D and Doppler echocardiography during exercise in the standing, sitting, or semi- supine position to detect provocable LV outflow tract obstruction in patients with hypertrophic cardiomyopathy, a history of syncope, and a resting or provoked peak instantaneous LV outflow tract gradient < 50 mmHg. B As per HRS/AHA/ACC 2017 guidelines: Do not obtain routine cardiac imaging in patients with syncope unless cardiac etiology is suspected based on initial evaluation (including history, physical examination, or ECG). D Consider obtaining a TTE in selected patients with suspected structural heart disease. C As per ESC 2014 guidelines, obtain resting and exercise 2D and Doppler echocardiography to identify the cause of symptoms in patients with unexplained syncope. B Cardiac imaging (CT/MRI): consider obtaining cardiac CT or MRI in selected patients presenting with syncope of suspected cardiac etiology. C https://web.pathway.md/diseases/recxj98tkWyAz2A9n 5/9 6/24/23, 3:14 PM Syncope Pathway Exercise stress testing: As per ESC 2018 guidelines, obtain exercise testing in patients experiencing syncope during or shortly after exertion. B Show 2 more As per AHA 2017 guidelines, consider obtaining exercise stress testing to establish the cause of syncope in selected patients experiencing syncope or presyncope during exertion. C As per ESC 2014 guidelines, obtain upright exercise testing to identify the cause of symptoms in patients with unexplained syncope. B Chest imaging: consider obtaining a CXR in patients with presyncope or syncope with a low probability of cardiovascular etiology based on history, physical examination, and ECG findings. C Neurological evaluation: obtain neurological evaluation when syncope is due to autonomic failure to evaluate the underlying disease. B Show 2 more Cerebrovascular imaging: As per ESC 2018 guidelines: Do not obtain neck ultrasound or brain MRI/CT in patients with syncope. D Obtain brain MRI in patients with neurological findings indicating Parkinsonism, ataxia, or cognitive impairment. B As per AHA 2017 guidelines: Do not obtain MRI or CT of the head in the routine evaluation of patients with syncope without focal neurological findings or head injury requiring further evaluation. D Do not obtain carotid artery imaging in the routine evaluation of patients with syncope without focal neurological findings on examination. D Electroencephalogram: As per ESC 2018 guidelines: Do not obtain an EEG in patients with syncope. D Consider obtaining tilt testing, preferably with concurrent EEG and video monitoring, for the diagnosis of psychogenic pseudosyncope. C As per AHA 2017 guidelines, do not obtain an EEG routinely in patients with syncope with no specific neurological features suggestive of a seizure. D Laboratory testing: As per ESC 2018 guidelines, obtain testing for paraneoplastic antibodies and anti-ganglionic AChR antibodies in patients with acute or subacute onset of multidomain autonomic failure. B As per ACC 2017 guidelines, do not obtain routine and comprehensive laboratory testing in patients with syncope. D Show 2 more https://web.pathway.md/diseases/recxj98tkWyAz2A9n 6/9 6/24/23, 3:14 PM Syncope Pathway Genetic testing: obtain further evaluation for genetic arrhythmia syndromes in young patients (aged < 40 years) with unexplained sudden cardiac arrest, unexplained near-drowning, or recurrent exertional syncope in the absence of ischemic or other structural heart diseases. B 4. Diagnostic procedures Electrophysiological studies: As per ESC 2022 guidelines, consider obtaining electrophysiological evaluation when syncope remains unexplained after noninvasive evaluation in patients with dilated cardiomyopathy/hypokinetic non-dilated cardiomyopathy. C As per ESC 2021 guidelines: Consider obtaining electrophysiological studies in patients with syncope and bifascicular block when syncope remains unexplained after noninvasive evaluation or when an immediate decision about pacing is needed due to severity unless empirical pacemaker implantation is preferred (especially in elderly and frail patients). C Consider obtaining electrophysiological studies in patients with syncope and sinus bradycardia when noninvasive evaluations have failed to show a correlation between syncope and bradycardia. C As per ACC 2019 guidelines: Consider evaluating sinus node function as part of the electrophysiology study in patients with symptoms suggestive of bradycardia (such as syncope, lightheadedness) undergoing an electrophysiology study for another indication. C Consider obtaining an electrophysiology study in patients with symptoms suggestive of intermittent bradycardia (such as lightheadedness, syncope) with conduction system disease identified by ECG and no demonstrated AV block. C As per ESC 2018 guidelines, obtain electrophysiological studies in patients with unexplained syncope (after noninvasive evaluation) and previous myocardial infarction or other scar-related conditions. B Show 3 more As per ACC 2018 guidelines, consider obtaining electrophysiologic testing for assessing the risk of sustained VT in patients with ischemic or non-ischemic cardiomyopathy or adult congenital heart disease having syncope or other ventricular arrhythmia symptoms and not meeting indications for a primary prevention ICD. C As per AHA 2017 guidelines, consider obtaining electrophysiological studies in selected patients with syncope of suspected arrhythmic etiology. C Show 2 more Coronary angiography: consider obtaining coronary angiography in patients with syncope for to the same indications as in patients without syncope. C https://web.pathway.md/diseases/recxj98tkWyAz2A9n 7/9 6/24/23, 3:14 PM Syncope Pathway 5. Medical management Setting of care: As per ESC 2018 guidelines, discharge patients with low-risk features, likely to have reflex syncope or situational syncope, or syncope due to orthostatic hypotension, from the emergency department. B Show 3 more As per AHA 2017 guidelines, consider managing patients with presumptive reflex-mediated syncope without serious medical conditions in an outpatient setting. C Show 3 more Management of reflex syncope (general principles): Explain the diagnosis, provide reassurance, and explain the risk of recurrence and the avoidance of triggers and situations in all patients. B Consider modifying or discontinuing hypotensive drugs in patients with vasodepressor syncope, if possible. C Management of reflex syncope (nonpharmacological management): Consider offering isometric physical counter-pressure maneuvers in < 60 years old patients with prodromes. C Consider offering tilt training for the education of young patients. C Management of reflex syncope (pharmacotherapy): consider offering fludrocortisone in young patients with the orthostatic form of vasovagal syncope, low-normal values of arterial BP, and the absence of contraindication to the drug. C Show 2 more Management of reflex syncope, cardiac pacing: As per ESC 2021 guidelines, perform dual-chamber pacing to reduce recurrent syncope in patients aged > 40 years, with severe, unpredictable, recurrent syncope having any of the following: spontaneous documented symptomatic asystolic pauses > 3 sec or asymptomatic pauses > 6 sec due to sinus arrest or AV block cardioinhibitory carotid sinus syndrome asystolic syncope during tilt testing. A Show 2 more As per ESC 2018 guidelines, consider performing cardiac pacing to reduce syncopal recurrences in > 40 years old patients with spontaneous documented symptomatic asystolic pauses > 3 seconds or asymptomatic pauses > 6 seconds due to sinus arrest, AV block, or both. C Show 3 more Management of carotid sinus syndrome: As per ESC 2018 guidelines, consider performing cardiac pacing to reduce syncopal recurrences in > 40 years old patients with cardioinhibitory carotid sinus syndrome with https://web.pathway.md/diseases/recxj98tkWyAz2A9n 8/9 6/24/23, 3:14 PM Syncope Pathway recurrent frequent unpredictable syncope. C As per ACC 2017 guidelines: Consider performing permanent cardiac pacing in patients with carotid sinus syndrome (cardioinhibitory or mixed). C Consider performing dual-chamber pacing in patients with carotid sinus syndrome requiring permanent pacing. C Management of vasovagal syncope (general principles): Educate patients with vasovagal syncope about their diagnosis and prognosis. B Consider reducing or withdrawing medications causing hypotension when appropriate in selected patients with vasovagal syncope. C Management of vasovagal syncope (nonpharmacological management): consider offering physical counter-pressure maneuvers in patients with vasovagal syncope having a sufficiently long prodromal period. C Show 2 more Management of vasovagal syncope (pharmacotherapy): consider offering midodrine in patients with recurrent vasovagal syncope with no history of hypertension, HF, or urinary retention. C Show 3 more Management of vasovagal syncope (cardiac pacing): consider performing dual-chamber pacing in selected 40 years old patients with recurrent vasovagal syncope and prolonged spontaneous pauses. C Management of OH-induced syncope, general principles: As per ESC 2018 guidelines, explain the diagnosis, provide reassurance, and explain the risk of recurrence and the avoidance of triggers and situations in all patients. B Show 2 more As per HRS/AHA/ACC 2017 guidelines, advise acute water ingestion for occasional, temporary relief in patients with syncope caused by neurogenic orthostatic hypotension. B Administer fluid resuscitation via PO or IV bolus in patients with syncope due to acute dehydration. B Show 2 more Management of OH-induced syncope, nonpharmacological management: As per ESC 2018 guidelines, consider offering isometric physical counter-pressure maneuvers. C Show 2 more As per HRS/AHA/ACC 2017 guidelines: Consider offering physical counter-pressure maneuvers in patients with syncope due to neurogenic orthostatic hypotension. C Consider offering compression garments in patients with syncope and orthostatic hypotension. C Management of OH-induced syncope, pharmacotherapy: https://web.pathway.md/diseases/recxj98tkWyAz2A9n 9/9