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  • Author: Rumm Morag, MD, FACEP; Chief Editor: Erik D Schraga, MD  more...
Updated: Dec 07, 2015

Practice Essentials

Syncope is defined as a transient, self-limited loss of consciousness[1] with an inability to maintain postural tone that is followed by spontaneous recovery. This definition excludes seizures, coma, shock, or other states of altered consciousness. Although most causes of syncope are benign, this symptom presages a life-threatening event in a small subset of patients.

Signs and symptoms

History and physical examination are the most specific and sensitive ways of evaluating syncope. These measures, along with 12-lead electrocardiography (ECG), are the only current level A recommendations listed in the 2007 American College of Emergency Physicians (ACEP) Clinical Policy on Syncope.[2]

A detailed account of the event must be obtained from the patient, including the following:

  • Precipitant factors
  • Activity the patient was involved in before the event
  • Position the patient was in when the event occurred

The following questions should be asked:

  • Was loss of consciousness complete?
  • Was loss of consciousness with rapid onset and short duration?
  • Was recovery spontaneous, complete, and without sequelae?
  • Was postural tone lost?

If the answers are positive, syncope is highly likely; if 1 or more are negative, other forms of loss of consciousness should be considered.[3]

Presyncopal symptoms reported may include the following:

  • Prior faintness, dizziness, or light-headedness (70% of cases of true syncope)
  • Prior vertigo, weakness, diaphoresis, epigastric discomfort, nausea, blurred or faded vision, pallor, or paresthesias
  • Red flag symptoms: Exertional onset, chest pain, dyspnea, low back pain, palpitations, severe headache, focal neurologic deficits, diplopia, ataxia, or dysarthria

Other information that should be obtained includes the following:

  • Detailed account of the event from any available witnesses (eg, whether patient experienced postevent confusion)
  • Patient’s medication history
  • Patient’s personal or familial medical history of cardiac disease

A complete physical examination is required, with particular attention to the following:

  • Analysis of vital signs
  • Measurement of the glucose level by rapid fingerstick
  • Detailed cardiopulmonary examination
  • Detailed neurologic examination
  • Assessment for signs of trauma
  • Stool guaiac examination (if appropriate, based on the patient's history)

See Clinical Presentation for more detail.


No specific laboratory testing has sufficient power to be absolutely indicated for evaluation of syncope. Tests may not be necessary and can be tailored to any signs or symptoms that raise concern for a specific underlying illness. Research-based and consensus guideline recommendations are as follows:

  • Serum glucose
  • Complete blood count
  • Serum electrolytes
  • Cardiac enzymes
  • Total creatine kinase
  • Urinalysis/dipstick

Imaging studies that may be helpful include the following:

  • Chest radiography: May serve to identify pneumonia, congestive heart failure (CHF), lung mass, effusion, or widened mediastinum
  • Computed tomography (CT) of the head (noncontrast): Has a low diagnostic yield in syncope but may be clinically indicated in patients with new neurologic deficits or in patients with head trauma secondary to syncope
  • CT of the chest and abdomen: Indicated only in select cases (eg, suspected aortic dissection, ruptured abdominal aortic aneurysm, or pulmonary embolism [PE])
  • Magnetic resonance imaging (MRI) of the brain and magnetic resonance arteriography (MRA): May be required in select cases to evaluate vertebrobasilar vasculature
  • Ventilation-perfusion (V/Q) scanning: Appropriate for suspected PE
  • Echocardiography: The test of choice for evaluating suspected mechanical cardiac causes of syncope

A standard 12-lead ECG is a level A recommendation in the 2007 ACEP consensus guidelines for syncope.[2] The following considerations are relevant:

  • Normal ECG findings are a good prognostic sign
  • ECG can be diagnostic for acute myocardial infarction or myocardial ischemia and can provide objective evidence of preexisting cardiac disease or dysrhythmia
  • Bradycardia, sinus pauses, nonsustained ventricular tachycardia and sustained ventricular tachycardia, and atrioventricular conduction defects are truly diagnostic only when they coincide with symptoms
  • Loop recorders have a higher diagnostic yield than Holter monitor evaluation, with a marginal cost savings [4]
  • Ambulatory monitoring appears to have a higher negative than positive diagnostic yield [5]

Other diagnostic tests and procedures include the following:

  • Head-up tilt-table test: Useful for confirming autonomic dysfunction and can generally be safely arranged on an outpatient basis
  • Electroencephalography (EEG): Can be performed at the discretion of a neurologist if seizure is considered a likely alternative diagnosis
  • Stress test: A cardiac stress test is appropriate for patients in whom cardiac syncope is suspected and who have risk factors for coronary atherosclerosis
  • Carotid sinus massage (to diagnose carotid sinus syncope)

See Workup for more detail.


Prehospital management of syncope may require the following:

  • Intravenous access
  • Oxygen administration
  • Advanced airway techniques
  • Glucose administration
  • Pharmacologic circulatory support
  • Pharmacologic or mechanical restraints
  • Defibrillation or temporary pacing

Advanced triage decisions, such as direct transport to multispecialty tertiary care centers, may be required in select cases.

In patients brought to the emergency department with a presumptive diagnosis of syncope, appropriate initial interventions may include the following:

  • IV access, oxygen administration, and cardiac monitoring
  • ECG and rapid blood glucose evaluation

The treatment choice for syncope depends on the cause or precipitant of the syncope, as follows:

Situational syncope: Patient education regarding the condition

  • Orthostatic syncope: Patient education; additional therapy in the form of thromboembolic disease (TED) stockings, mineralocorticoids, and other drugs (eg, midodrine); elimination of drugs associated with hypotension; intentional oral fluid consumption
  • Cardiac arrhythmic syncope: Antiarrhythmic drugs or pacemaker placement
  • Cardiac mechanical syncope: Beta blockade; if valvular disease is present, surgical correction

See Treatment and Medication for more detail.



Syncope is defined as a transient, self-limited loss of consciousness[1] with an inability to maintain postural tone that is followed by spontaneous recovery. The term syncope excludes seizures, coma, shock, or other states of altered consciousness.

Syncope is a prevalent disorder, accounting for 1-3% of emergency department (ED) visits and as many as 6% of hospital admissions each year in the United States. As much as 50% of the population may experience a syncopal event during their lifetime. Although many etiologies for syncope are recognized, categorization into reflex (neurally mediated), orthostatic, and cardiac (cardiovascular) may be helpful during the initial evaluation. Cardiac syncope is associated with increased mortality, whereas noncardiac syncope is not. Syncope may result in significant morbidity and disability due to falls or accidents that occur as a result.[6] In the United States alone, an estimated $2 billion annually is spent on patients hospitalized with syncope.

Although most causes of syncope are benign, this symptom presages a life-threatening event in a small subset of patients. It is unclear whether hospital inpatient admission of asymptomatic patients after syncope affects outcomes. No current criterion standard exists for diagnosing undifferentiated syncope. Many physicians continue to admit patients because of perceived risk. Recent reviews of the 2001 American College of Emergency Physician (ACEP) clinical policy suggest that evidence-based criteria may decrease admission rates by nearly half by identifying cardiac causes of syncope. Inpatient admission should be reserved for patients in whom identification of specific immediate risk, such as those with structural heart disease or history of ventricular arrhythmia, is needed. Outpatient management can be used for patients who are low risk for a cardiac etiology in order to define a precise cause in order to effect mechanism-specific treatment.



Syncope occurs due to global cerebral hypoperfusion.[1] Brain parenchyma depends on adequate blood flow to provide a constant supply of glucose, the primary metabolic substrate. Brain tissue cannot store energy in the form of high-energy phosphates found elsewhere in the body; therefore, a cessation of cerebral perfusion lasting only 3-5 seconds can result in syncope.

Cerebral perfusion is maintained relatively constant by an intricate and complex feedback system involving cardiac output, systemic vascular resistance, arterial pressure, intravascular volume status, cerebrovascular resistance with intrinsic autoregulation, and metabolic regulation. A clinically significant defect in any one of these or subclinical defects in several of these systems may cause syncope.

Cardiac output (CO) can be diminished secondary to mechanical outflow obstruction, pump failure, hemodynamically significant arrhythmias, or conduction defects. Systemic vascular resistance (SVR) can drop secondary to vasomotor instability, autonomic failure, or vasodepressor/vasovagal response. Mean arterial pressure (MAP) decreases with all causes of hypovolemia. Medications can affect CO, SVR, or MAP.

Other conditions can mimic syncope. A central nervous system event, such as a hemorrhage or an unwitnessed seizure, can present as syncope. Syncope can occur without reduction in cerebral blood flow in patients who have severe metabolic derangements (eg, hypoglycemia, hyponatremia, hypoxemia, hypercarbia).



Cardiac (cardiopulmonary) syncope may be due to vascular disease, cardiomyopathy, arrhythmia, or valvular dysfunction and predicts a worse short-term and long-term prognosis. Obtaining an initial ECG is mandatory if any of these causes are possible for the differential diagnosis.

Low flow states, such as those associated with advanced cardiomyopathy, CHF, and valvular insufficiency, may result in hypotension and cause transient global cerebral hypoperfusion. Often, these patients are on medications that reduce afterload, which may contribute to the cause of syncope.

Ventricular arrhythmias, such as ventricular tachycardia and torsade de pointes, tend to occur in older patients with known cardiac disease. These patients tend to have fewer recurrences and have a more sudden onset with few, if any, presyncopal symptoms. Associated chest pain or dyspnea may be present. This type of syncope is generally unrelated to posture and can occur during lying, sitting, or standing. Often, these arrhythmias are not revealed on the initial ECG but may be captured with prolonged monitoring.

Supraventricular tachyarrhythmias include supraventricular tachycardia and atrial fibrillation with rapid response. These may be associated with palpitations, chest pain, or dyspnea. Patients typically have prodromal symptoms and may have syncope while attempting to stand or walk because of resultant hypotension. These symptoms may spontaneously resolve prior to evaluation but are often noted during initial triage and assessment. Be sure to scrutinize ECG findings for evidence of Wolff-Parkinson-White syndromeBrugada syndrome, and long QT syndrome.

Bradyarrhythmias include sick sinus syndrome, sinus bradycardia, high-grade atrioventricular blocks, pacemaker malfunction, and adverse medication reactions. Generally, these patients have a history of cardiac problems and are symptomatic. Chest pain, dyspnea, decreased exercise tolerance, and fatigue may all be present. Consider cardiac ischemia and medication side effects as additional causes.

Cardiac outflow obstruction may also result in sudden-onset syncope with little or no prodrome. One critical clue is the exertional nature, and the other is the presence of a cardiac murmur. Young athletes may present with this etiology for syncope. Specific pathology includes aortic stenosis, hypertrophic obstructive cardiomyopathy, mitral stenosis, pulmonary stenosis, pulmonary embolus, left atrial myxoma, and pericardial tamponade.

Syncope can also result from an acute MI, acute aortic dissection, and pulmonary embolus. These conditions can have associated chest pain, neck pain, shoulder pain, dyspnea, epigastric pain, hypotension, alteration of mental status and can result in sudden death.

Reflex (neurally mediated) syncope may be due to vasovagal syncope, which is mediated by emotional distress such as fear or physical pain. Situational syncope describes syncope that occurs with a fixed event such as micturition, deglutition, exercise induced, and carotid sinus syncope. These causes tend to be more benign and do not predict poor outcomes.

Vasovagal syncope is the most common type in young adults but can occur at any age. It usually occurs in a standing position and is precipitated by fear, emotional stress, or pain (eg, after a needlestick). Autonomic symptoms are predominant. Classically, nausea, diaphoresis, fading or "graying out" of vision, epigastric discomfort, and light-headedness precede syncope by a few minutes. Syncope is thought to occur secondary to efferent vasodepressor reflexes by a number of mechanisms, resulting in decreased peripheral vascular resistance. It is not life threatening and occurs sporadically.

Situational syncope is essentially a reproducible vasovagal syncope with a known precipitant. Micturition, defecation, deglutition, tussive, and carotid sinus syncope are types of situational syncope. These stimuli result in autonomic reflexes with a vasodepressor response, ultimately leading to transient cerebral hypotension. These are not life-threatening but can cause morbidity. The treatment involves avoidance of the precipitant when possible and the initiation of counter maneuvers when anticipated.

Syncope due to orthostatic hypotension can occur through several mechanisms. Pure autonomic failure can be associated with Parkinson's disease or dementia. Secondary autonomic insufficiency can be due to diabetes, uremia, or spinal injury. Drugs such as alcohol cause orthostatic intolerance and medications such as vasodilators and antidepressants block orthostatic reflexes. Volume depletion due to blood loss, vomiting, diarrhea, poor oral intake, and diuretics also cause orthostatic syncope.

Dehydration and decreased intravascular volume contribute to orthostasis. Orthostatic syncope describes a causative relationship between orthostatic hypotension and syncope. Orthostatic hypotension increases in prevalence with age as a blunted baroreceptor response results in failure of compensatory cardioacceleration. In elderly patients, 45% of these cases are related to medications. Limited evidence suggests that polydipsia may reduce recurrences. Orthostasis is a common cause of syncope and tends to be recurrent. Bedside orthostatics cannot exclude this as an etiology; if suspected, patients should be referred to a primary care provider for outpatient tilt-table testing.



United States statistics

Framingham data demonstrate a first occurrence rate of 6.2 cases per 1000 patient-years.[7, 8]  Syncope reoccurs in 3% of affected individuals, and approximately 10% of affected individuals have a cardiac etiology.

International statistics

Data from Europe and Japan suggest a similar occurrence rate to the United States, accounting for 1-3.5% of emergency department visits.

Race-, sex-, and age-related demographics

No significant differences regarding race are observed with respect to syncope risk. Larger prospective studies fail to show clinically significant differences between men and women.

National Hospital Ambulatory Medical Care Survey (NHAMCS) data show that syncope occurs in all age groups but is most common in adult populations. Noncardiac causes tend to be more common in young adults, whereas cardiac syncope becomes increasingly more frequent with advancing age.

Syncope is relatively uncommon in pediatric populations. One small retrospective study by Pratt and Fleisher reported a prevalence of less than 0.1% in children.[9]  Pediatric syncope warrants prompt detailed evaluation.

Advancing age is an independent risk factor for both syncope and death. Various studies suggest categorizing patients older than 45 years, 65 years, and 80 years as "higher risk." Advancing age correlates with increasing frequency of coronary artery and myocardial disease, arrhythmia, vasomotor instability, autonomic failure, polyneuropathy, and use of polypharmacy.



Cardiac syncope has a poorer prognosis than other forms of syncope. The 1-year end point mortality rate has been shown to be as high as 18-33%. Studies evaluating mortality rates within 4 weeks of presentation and 1 year after presentation both report statistically significant increases in this patient group. Patients with cardiac syncope may be significantly restricted in their daily activities, and the occurrence of syncope may be a symptom of their underlying disease progression.

Syncope of any etiology in a patient with cardiac conditions (to be differentiated from cardiac syncope) has also been shown to imply a poor prognosis. Patients with New York Heart Association (NYHA) functional class III or IV who have any type of syncope have a mortality rate as high as 25% within 1 year.

However, some patients do well after definitive surgical treatment or pacemaker placement. Evaluation by a cardiologist for pacemaker placement should be considered in select patients over 40 years of age with recurrent syncope confirmed to be neurally-mediated syncope (NMS) with a documented period of asystole. Preliminary data suggests that although syncope may recur in this subset of patients there is a reduction in frequency of more than 50%.[10]

Noncardiac syncope seems to have no effect on overall mortality rates and includes syncope due to vasovagal response, autonomic insufficiency, situations, and orthostatic positions.

Vasovagal syncope has a uniformly excellent prognosis. This condition does not increase the mortality rate, and recurrences are infrequent.

Situational syncope and orthostatic syncope also have an excellent prognosis. They do not increase the risk of death; however, recurrences do occur and are sometimes a source of significant morbidity in terms of quality of life and secondary injury.

Syncope of unknown etiology generally has a favorable prognosis, with 1-year follow-up data showing a low incidence of sudden death (2%), a 20% chance of recurrent syncope, and a 78% remission rate.


Data suggest that patients with cardiac syncope are more likely to experience a poor outcome. Patients who have a significant cardiac history and those who seem to have a cardiac syncope (because of associated chest pain, dyspnea, cardiac murmur, signs of congestive heart failure [CHF], or ECG abnormalities) should be considered to be at increased risk. Most published methods of risk stratification take into account cardiac symptoms and risk factors.

Morbidity from syncope includes recurrent syncope, which occurs in 20% of patients within one year of the initial episode. Lacerations, extremity fractures, head injuries, and motor vehicle accidents can occur secondary to syncope.

Syncope in a patient with poor baseline cardiac function portends a poor prognosis irrespective of etiology. Middlekauff et al studied 491 patients with NYHA functional class III or IV disease and noted that, regardless of the cause, 45% of those with syncope died within 1 year, whereas 12% of those without syncope died during the same interval.[11]

Patients with cardiac syncope appear to do worse than patients with noncardiac syncope. Soteriades et al followed 7814 patients with syncope for 17 years and found a higher mortality rate for patients with cardiac syncope compared with noncardiac syncope.[12]  Suzuki et al studied 912 patients with syncope for an average of 3 years and found the same result.[13]

Risk of serious outcome and death in patients with syncope increases with higher peak troponin concentrations, according to a prospective cohort study of 338 patients who had plasma troponin I levels measured 12 hours after syncope, using a sensitive assay.[14]  The percentage of patients with a serious outcome increased across patients divided into quintiles on the basis of peak troponin concentration at 1 month (0%, 9%, 13%, 26%, 70%) and at 1 year (10%, 22%, 26%, 52%, 85%).[14]

Decision rules may assist in identifying patients who are at risk. Martin et al describes a risk stratification system that predicts an increased incidence of death at 1 year based on the presence of abnormal electrocardiographic (ECG) findings, a history of ventricular arrhythmia, a history of CHF, and age older than 45 years.[15]

Sarasin et al demonstrates a risk of arrhythmia that is proportional to the number of cardiac risk factors, including abnormal ECG findings, history of CHF, and age older than 65 years.[16]

The San Francisco Syncope Rule identifies patients who are at immediate risk for serious outcomes within 7 days, with a 96% sensitivity based on the presence of abnormal ECG findings, a history of CHF, dyspnea, a hematocrit level of less than 30, and hypotension.[17]  The presence of these findings should prompt serious consideration for hospital admission. In an external retrospective review, validation of the San Francisco Syncope Rule in a Canadian emergency department was undertaken. The rule performed with a sensitivity of 90% (44/49 outcomes; 95% confidence interval [CI] 79-96%) and a specificity of 33%, which was much lower than previously reported. Based on results of this study, implementation of this rule would have significantly increased admission rates. These authors concluded further study is needed.[18]  Another study was also unable to validate the rule, with sensitivity of 74% and specificity of 57% reported.[19]

The Risk stratification Of Syncope in the Emergency department, or ROSE, criteria suggest that an elevated B-type natriuretic peptide (BNP), Hemoccult positive stool, anemia, low oxygen saturation, and presence of Q waves on ECG predict serious outcomes at 30 days.[20]  These rules had a 87% sensitivity and a 98.5% negative predictive value to help risk stratify patients. In this study, the isolated finding of BNP greater than 300 pg/mL was a major predictor of serious outcomes and was present in 89% of patients who died within 30 days.

Constantino et al discovered that 6.1% of patients had severe outcomes within 10 days of syncope evaluation.[21]  The mortality rate was 0.7%, and 5.4% of patients were readmitted or experienced major therapeutic intervention. Risk factors associated with severe short-term outcomes included abnormal ECG, history of CHF, age older than 65 years, male gender, history of chronic obstructive pulmonary disease (COPD), structural heart disease, presence of trauma, and lack of prodromal symptoms.

The Evaluation of Guidelines in SYncope Study 2 (EGSYS 2) prospectively followed nearly 400 patients at 1 month and 2 years. The death rate was 2% at 1 month and 9% at 2 years. Patients with advancing age, presence of structural heart disease, and/or abnormal ECG had higher risk.[22]

Clinical judgement, Osservatorio Epidemiologico sulla Sincope nel Lazio (OESIL) score, and San Francisco Syncope Rule all have relatively low sensitivities individually for predicting severe short-term outcomes. Some evidence suggests that combining various risk stratification tools may increase sensitivity and reduce unnecessary admissions.[23]  A review and meta-analysis by Serrano et al assessed the methodological quality and prognostic accuracy of the San Francisco Syncope Rule and the OESIL risk score.[24]  The analysis of 18 eligible studies determined that the quality and accuracy of both sets of clinical decision rules are limited.


Patients with recurrent syncope should be cautioned to avoid tall ledges and to refrain from driving.

Recurrent falls due to syncope can result in lacerations, orthopedic injuries, and intracranial trauma.


Patient Education

Patients who present to the emergency department with syncope should be instructed not to drive. Syncope-related injury during driving is rare, but it has been documented.

Education may have a substantial impact on the prevention of recurrence, especially in situational and orthostatic syncope.

Patients may be trained to avoid situations that prompt syncope in situational cases.

In orthostatic syncope, patients should drink 500 mL of fluid each morning in addition to their usual routine and should avoid standing up too quickly.

For patient education resources, see Brain and Nervous System Center, as well as Fainting.

Contributor Information and Disclosures

Rumm Morag, MD, FACEP Member of Salem Emergency Physician Services, PC (SEPS), Salem Hospital

Rumm Morag, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.


Barry E Brenner, MD, PhD, FACEP Professor of Emergency Medicine, Professor of Internal Medicine, Program Director for Emergency Medicine, Case Medical Center, University Hospitals, Case Western Reserve University School of Medicine

Barry E Brenner, MD, PhD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Heart Association, American Thoracic Society, Arkansas Medical Society, New York Academy of Medicine, New York Academy of Sciences, Society for Academic Emergency Medicine, American Academy of Emergency Medicine, American College of Chest Physicians, American College of Emergency Physicians, American College of Physicians

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Eddy S Lang, MDCM, CCFP(EM), CSPQ Associate Professor, Senior Researcher, Division of Emergency Medicine, Department of Family Medicine, University of Calgary Faculty of Medicine; Assistant Professor, Department of Family Medicine, McGill University Faculty of Medicine, Canada

Eddy S Lang, MDCM, CCFP(EM), CSPQ is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, Canadian Association of Emergency Physicians

Disclosure: Nothing to disclose.

Chief Editor

Erik D Schraga, MD Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Disclosure: Nothing to disclose.

Additional Contributors

David A Peak, MD Associate Residency Director of Harvard Affiliated Emergency Medicine Residency; Attending Physician, Massachusetts General Hospital; Assistant Professor, Harvard Medical School

David A Peak, MD is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, Undersea and Hyperbaric Medical Society, American Medical Association

Disclosure: Partner received salary from Pfizer for employment.

  1. Walsh K, Hoffmayer K, Hamdan MH. Syncope: diagnosis and management. Curr Probl Cardiol. 2015 Feb. 40 (2):51-86. [Medline].

  2. [Guideline] Huff JS, Decker WW, Quinn JV, et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with syncope. Ann Emerg Med. 2007 Apr. 49(4):431-44. [Medline]. [Full Text].

  3. Moya A, Sutton R, Ammirati F, et al. 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 (ESC). Eur Heart J. 2009 Nov. 30(21):2631-71. [Medline].

  4. Rockx MA, Hoch JS, Klein GJ, et al. Is ambulatory monitoring for "community-acquired" syncope economically attractive? A cost-effectiveness analysis of a randomized trial of external loop recorders versus Holter monitoring. Am Heart J. 2005 Nov. 150(5):1065. [Medline].

  5. Gibson TC, Heitzman MR. Diagnostic efficacy of 24-hour electrocardiographic monitoring for syncope. Am J Cardiol. 1984 Apr 1. 53(8):1013-7. [Medline].

  6. Ungar A, Mussi C, Nicosia F, et al. The "syncope and dementia" study: a prospective, observational, multicenter study of elderly patients with dementia and episodes of "suspected" transient loss of consciousness. Aging Clin Exp Res. 2015 Dec. 27 (6):877-82. [Medline].

  7. Chen L, Chen MH, Larson MG, Evans J, Benjamin EJ, Levy D. Risk factors for syncope in a community-based sample (the Framingham Heart Study). Am J Cardiol. 2000 May 15. 85(10):1189-93. [Medline].

  8. Savage DD, Corwin L, McGee DL, Kannel WB, Wolf PA. Epidemiologic features of isolated syncope: the Framingham Study. Stroke. 1985 Jul-Aug. 16(4):626-9. [Medline].

  9. Pratt JL, Fleisher GR. Syncope in children and adolescents. Pediatr Emerg Care. 1989 Jun. 5(2):80-2. [Medline].

  10. Brignole M, Menozzi C, Moya A, et al. Pacemaker therapy in patients with neurally mediated syncope and documented asystole: Third International Study on Syncope of Uncertain Etiology (ISSUE-3): a randomized trial. Circulation. 2012 May 29. 125(21):2566-71. [Medline].

  11. Middlekauff HR, Stevenson WG, Stevenson LW, Saxon LA. Syncope in advanced heart failure: high risk of sudden death regardless of origin of syncope. J Am Coll Cardiol. 1993 Jan. 21(1):110-6. [Medline].

  12. Soteriades ES, Evans JC, Larson MG, et al. Incidence and prognosis of syncope. N Engl J Med. 2002 Sep 19. 347(12):878-85. [Medline].

  13. Suzuki M, Hori S, Nakamura I, Soejima K, Aikawa N. Long-term survival of Japanese patients transported to an emergency department because of syncope. Ann Emerg Med. 2004 Sep. 44(3):215-21. [Medline].

  14. Reed MJ, Mills NL, Weir CJ. Sensitive troponin assay predicts outcome in syncope. Emerg Med J. 2012 Dec. 29(12):1001-3. [Medline].

  15. Martin TP, Hanusa BH, Kapoor WN. Risk stratification of patients with syncope. Ann Emerg Med. 1997 Apr. 29(4):459-66. [Medline].

  16. Sarasin FP, Hanusa BH, Perneger T, Louis-Simonet M, Rajeswaran A, Kapoor WN. A risk score to predict arrhythmias in patients with unexplained syncope. Acad Emerg Med. 2003 Dec. 10(12):1312-7. [Medline].

  17. Quinn JV, Stiell IG, McDermott DA, Sellers KL, Kohn MA, Wells GA. Derivation of the San Francisco Syncope Rule to predict patients with short-term serious outcomes. Ann Emerg Med. 2004 Feb. 43(2):224-32. [Medline].

  18. Thiruganasambandamoorthy V, Hess EP, Alreesi A, Perry JJ, Wells GA, Stiell IG. External validation of the San Francisco Syncope Rule in the Canadian setting. Ann Emerg Med. 2010 May. 55(5):464-72. [Medline].

  19. Birnbaum A, Esses D, Bijur P, Wollowitz A, Gallagher EJ. Failure to validate the San Francisco Syncope Rule in an independent emergency department population. Ann Emerg Med. 2008 Aug. 52(2):151-9. [Medline].

  20. Reed MJ, Newby DE, Coull AJ, Prescott RJ, Jacques KG, Gray AJ. The ROSE (risk stratification of syncope in the emergency department) study. J Am Coll Cardiol. 2010 Feb 23. 55(8):713-21. [Medline].

  21. Costantino G, Perego F, Dipaola F, et al. Short- and long-term prognosis of syncope, risk factors, and role of hospital admission: results from the STePS (Short-Term Prognosis of Syncope) study. J Am Coll Cardiol. 2008 Jan 22. 51(3):276-83. [Medline].

  22. Andrea U, Attilio DR, Franco G, et al. Early and late outcome of treated patients referred for syncope to emergency department: the EGSYS 2 follow-up study. Eur Heart J. 2010 Feb 18. [Medline].

  23. Dipaola F, Costantino G, Perego F, Borella M, Galli A, Cantoni G. San Francisco Syncope Rule, Osservatorio Epidemiologico sulla Sincope nel Lazio risk score, and clinical judgment in the assessment of short-term outcome of syncope. Am J Emerg Med. 2010 May. 28(4):432-9. [Medline].

  24. Serrano LA, Hess EP, Bellolio MF, et al. Accuracy and quality of clinical decision rules for syncope in the emergency department: a systematic review and meta-analysis. Ann Emerg Med. 2010 Oct. 56(4):362-373.e1. [Medline].

  25. Atkins D, Hanusa B, Sefcik T, Kapoor W. Syncope and orthostatic hypotension. Am J Med. 1991 Aug. 91(2):179-85. [Medline].

  26. Calkins H, Shyr Y, Frumin H, Schork A, Morady F. The value of the clinical history in the differentiation of syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope. Am J Med. 1995 Apr. 98(4):365-73. [Medline].

  27. Martin GJ, Adams SL, Martin HG, Mathews J, Zull D, Scanlon PJ. Prospective evaluation of syncope. Ann Emerg Med. 1984 Jul. 13(7):499-504. [Medline].

  28. Azizi Malamiri R, Momen AA, Nikkhah A, et al. Usability of the head upright tilt test for differentiating between syncopal and seizure-like events in children. Acta Neurol Belg. 2015 Dec. 115 (4):575-9. [Medline].

  29. Klemenc M, Strumbelj E. Predicting the outcome of head-up tilt test using heart rate variability and baroreflex sensitivity parameters in patients with vasovagal syncope. Clin Auton Res. 2015 Dec. 25 (6):391-8. [Medline].

  30. Quinn J, McDermott D. Electrocardiogram findings in emergency department patients with syncope. Acad Emerg Med. 2011 Jul. 18(7):714-8. [Medline].

  31. Shen WK, Decker WW, Smars PA, et al. Syncope Evaluation in the Emergency Department Study (SEEDS): a multidisciplinary approach to syncope management. Circulation. 2004 Dec 14. 110(24):3636-45. [Medline].

  32. Bachinsky WB, Linzer M, Weld L, Estes NA 3rd. Usefulness of clinical characteristics in predicting the outcome of electrophysiologic studies in unexplained syncope. Am J Cardiol. 1992 Apr 15. 69(12):1044-9. [Medline].

  33. Baron-Esquivias G, Errazquin F, Pedrote A, et al. Long-term outcome of patients with vasovagal syncope. Am Heart J. 2004 May. 147(5):883-9. [Medline].

  34. Bass EB, Curtiss EI, Arena VC, et al. The duration of Holter monitoring in patients with syncope. Is 24 hours enough?. Arch Intern Med. 1990 May. 150(5):1073-8. [Medline].

  35. Benditt DG, Can I. Initial evaluation of "syncope and collapse" the need for a risk stratification consensus. J Am Coll Cardiol. 2010 Feb 23. 55(8):722-4. [Medline].

  36. Bhatia A, Dhala A, Blanck Z, Deshpande S, Akhtar M, Sra AJ. Driving safety among patients with neurocardiogenic (vasovagal) syncope. Pacing Clin Electrophysiol. 1999 Nov. 22(11):1576-80. [Medline].

  37. Calkins H, Shyr Y, Frumin H, Schork A, Morady F. The value of the clinical history in the differentiation of syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope. Am J Med. 1995 Apr. 98(4):365-73. [Medline].

  38. Claydon VE, Schroeder C, Norcliffe LJ, Jordan J, Hainsworth R. Water drinking improves orthostatic tolerance in patients with posturally related syncope. Clin Sci (Lond). 2006 Mar. 110(3):343-52. [Medline].

  39. Colivicchi F, Ammirati F, Melina D, Guido V, Imperoli G, Santini M. 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 May. 24(9):811-9. [Medline].

  40. Crane SD. Risk stratification of patients with syncope in an accident and emergency department. Emerg Med J. 2002 Jan. 19(1):23-7. [Medline].

  41. Day SC, Cook EF, Funkenstein H, Goldman L. Evaluation and outcome of emergency room patients with transient loss of consciousness. Am J Med. 1982 Jul. 73(1):15-23. [Medline].

  42. Denes P, Uretz E, Ezri MD, Borbola J. Clinical predictors of electrophysiologic findings in patients with syncope of unknown origin. Arch Intern Med. 1988 Sep. 148(9):1922-8. [Medline].

  43. Dovgalyuk J, Holstege C, Mattu A, Brady WJ. The electrocardiogram in the patient with syncope. Am J Emerg Med. 2007 Jul. 25(6):688-701. [Medline].

  44. Eagle KA, Black HR. The impact of diagnostic tests in evaluating patients with syncope. Yale J Biol Med. 1983 Jan-Feb. 56(1):1-8. [Medline]. [Full Text].

  45. Eagle KA, Black HR, Cook EF, Goldman L. Evaluation of prognostic classifications for patients with syncope. Am J Med. 1985 Oct. 79(4):455-60. [Medline].

  46. Farwell DJ, Sulke AN. Does the use of a syncope diagnostic protocol improve the investigation and management of syncope?. Heart. 2004 Jan. 90(1):52-8. [Medline].

  47. Freed LA, Eagle KA, Mahjoub ZA, et al. Gender differences in presentation, management, and cardiac event-free survival in patients with syncope. Am J Cardiol. 1997 Nov 1. 80(9):1183-7. [Medline].

  48. Gatzoulis K, Sideris S, Theopistou A, Sotiropoulos H, Stefanadis C, Toutouzas P. Long-term outcome of patients with recurrent syncope of unknown cause in the absence of organic heart disease and relation to results of baseline tilt table testing. Am J Cardiol. 2003 Oct 1. 92(7):876-9. [Medline].

  49. Glasser SP, Clark PI, Applebaum HJ. Occurrence of frequent complex arrhythmias detected by ambulatory monitoring: findings in an apparently healthy asymptomatic elderly population. Chest. 1979 May. 75(5):565-8. [Medline].

  50. Hammill SC. Value and limitations of noninvasive assessment of syncope. Cardiol Clin. 1997 May. 15(2):195-218. [Medline].

  51. Harding A. Head-up Tilt Test Useful for Ruling Out Epilepsy in Patients With Syncope: Study. Medscape Medical News. Available at Accessed: April 8, 2014.

  52. Henderson MC, Prabhu SD. Syncope: current diagnosis and treatment. Curr Probl Cardiol. 1997 May. 22(5):242-96. [Medline].

  53. Hilgard J, Ezri MD, Denes P. Significance of ventricular pauses of three seconds or more detected on twenty-four-hour Holter recordings. Am J Cardiol. 1985 Apr 1. 55(8):1005-8. [Medline].

  54. Junaid A, Dubinsky IL. Establishing an approach to syncope in the emergency department. J Emerg Med. 1997 Sep-Oct. 15(5):593-9. [Medline].

  55. Kapoor WN. Diagnostic evaluation of syncope. Am J Med. 1991 Jan. 90(1):91-106. [Medline].

  56. Kapoor WN. Evaluation and management of the patient with syncope. JAMA. 1992 Nov 11. 268(18):2553-60. [Medline].

  57. Kapoor WN, Karpf M, Wieand S, Peterson JR, Levey GS. A prospective evaluation and follow-up of patients with syncope. N Engl J Med. 1983 Jul 28. 309(4):197-204. [Medline].

  58. Krahn AD, Klein GJ, Yee R, Hoch JS, Skanes AC. Cost implications of testing strategy in patients with syncope: randomized assessment of syncope trial. J Am Coll Cardiol. 2003 Aug 6. 42(3):495-501. [Medline].

  59. Krahn AD, Klein GJ, Yee R, Takle-Newhouse T, Norris C. Use of an extended monitoring strategy in patients with problematic syncope. Reveal Investigators. Circulation. 1999 Jan 26. 99(3):406-10. [Medline].

  60. Kushner JA, Kou WH, Kadish AH, Morady F. Natural history of patients with unexplained syncope and a nondiagnostic electrophysiologic study. J Am Coll Cardiol. 1989 Aug. 14(2):391-6. [Medline].

  61. Linzer M, Pritchett EL, Pontinen M, McCarthy E, Divine GW. Incremental diagnostic yield of loop electrocardiographic recorders in unexplained syncope. Am J Cardiol. 1990 Jul 15. 66(2):214-9. [Medline].

  62. Lu CC, Diedrich A, Tung CS, et al. Water ingestion as prophylaxis against syncope. Circulation. 2003 Nov 25. 108(21):2660-5. [Medline].

  63. McIntosh S, Da Costa D, Kenny RA. Outcome of an integrated approach to the investigation of dizziness, falls and syncope in elderly patients referred to a 'syncope' clinic. Age Ageing. 1993 Jan. 22(1):53-8. [Medline].

  64. Meyer MD, Handler J. Evaluation of the patient with syncope: an evidence based approach. Emerg Med Clin North Am. 1999 Feb. 17(1):189-201, ix. [Medline].

  65. Mozes B, Confino-Cohen R, Halkin H. Cost-effectiveness of in-hospital evaluation of patients with syncope. Isr J Med Sci. 1988 Jun. 24(6):302-6. [Medline].

  66. Narkiewicz K, Cooley RL, Somers VK. Alcohol potentiates orthostatic hypotension : implications for alcohol-related syncope. Circulation. 2000 Feb 1. 101(4):398-402. [Medline].

  67. Parry SW, Tan MP. An approach to the evaluation and management of syncope in adults. BMJ. 2010 Feb 19. 340:c880. [Medline].

  68. Racco F, Sconocchini C, Alesi C, Zappelli L, Pratillo G. Long-term follow-up after syncope. A group of 183 patients observed for 5 years. Minerva Cardioangiol. 2000 Mar. 48(3):69-78. [Medline].

  69. Rangel I, Freitas J, Correia AS, Sousa A, Lebreiro A, de Sousa C, et al. The usefulness of the head-up tilt test in patients with suspected epilepsy. Seizure. 2014 Feb 17. [Medline].

  70. Sarasin FP, Louis-Simonet M, Carballo D, et al. Prospective evaluation of patients with syncope: a population-based study. Am J Med. 2001 Aug 15. 111(3):177-84. [Medline].

  71. Sheldon R, Connolly S, Rose S, et al. Prevention of Syncope Trial (POST): a randomized, placebo-controlled study of metoprolol in the prevention of vasovagal syncope. Circulation. 2006 Mar 7. 113(9):1164-70. [Medline].

  72. Sloane PD, Linzer M, Pontinen M, Divine GW. Clinical significance of a dizziness history in medical patients with syncope. Arch Intern Med. 1991 Aug. 151(8):1625-8. [Medline].

  73. Sun BC, Derose SF, Liang LJ, et al. Predictors of 30-day serious events in older patients with syncope. Ann Emerg Med. 2009 Dec. 54(6):769-778.e1-5. [Medline]. [Full Text].

  74. Tan MP, Parry SW. Vasovagal syncope in the older patient. J Am Coll Cardiol. 2008 Feb 12. 51(6):599-606. [Medline].

  75. Tretter JT, Kavey RE. Distinguishing cardiac syncope from vasovagal syncope in a referral population. J Pediatr. 2013 Dec. 163(6):1618-1623.e1. [Medline].

  76. Guse SE, Neuman MI, O'Brien M, et al. Implementing a guideline to improve management of syncope in the emergency department. Pediatrics. 2014 Nov. 134 (5):e1413-21. [Medline].

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