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Syncope - Approach to the Patient

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General Information

General InformationGeneral Information

Description

  • syndrome of transient loss of consciousness secondary to cerebral hypoperfusion characterized by rapid onset, short duration, and complete spontaneous recovery1,4

Also called

  • fainting

Definitions

  • presyncope may be used as noun or adjective1
    • noun refers to state that resembles prodrome of syncope but that is not followed by loss of consciousness
    • adjective refers to symptoms or signs that occur before loss of consciousness
  • transient loss of consciousness defined as state of real or apparent loss of consciousness with loss of awareness characterized by amnesia for unconscious period, abnormal motor control, loss of responsiveness, and short duration1
  • true loss of consciousness refers to failure of both arousal and self-awareness2

Types

  • neurally mediated (reflex syncope)1
  • orthostatic syncope, including autonomic dysfunction1
  • cardiac syncope, including arrhythmia and structural disease causes1

References

General references used

  1. Brignole M, Moya A, de Lange FJ, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J. 2018 Jun 1;39(21):1883-1948OpenInNewfull-textOpenInNew
  2. Jhanjee R, van Dijk JG, Sakaguchi S, Benditt DG. Syncope in adults: terminology, classification, and diagnostic strategy. Pacing Clin Electrophysiol. 2006 Oct;29(10):1160-9OpenInNew
  3. Saklani P, Krahn A, Klein G. Syncope. Circulation. 2013 Mar 26;127(12):1330-9OpenInNewfull-textOpenInNew
  4. Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. J Am Coll Cardiol 2017 Aug 1;70(5):620OpenInNewfull-textOpenInNew

Recommendation grading systems used

  • American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) grading system for recommendations
    • classifications of recommendations
      • Class I - procedure or treatment should be performed or administered
      • Class IIa - reasonable to perform procedure or administer treatment, but additional studies with focused objectives needed
      • Class IIb - procedure or treatment may be considered; additional studies with broad objectives needed, additional registry data would be useful
      • Class III - procedure or treatment should not be performed or administered because it is not helpful or may be harmful
        • Class III ratings may be subclassified as Class III No Benefit or Class III Harm
    • levels of evidence
      • Level A - high-quality evidence from > 1 randomized controlled trial or meta-analysis of high-quality randomized controlled trials
      • Level B-R - moderate-quality evidence from ≥ 1 randomized controlled trial or meta-analysis of moderate-quality randomized controlled trials
      • Level B-NR - moderate-quality evidence from ≥ 1 well-designed nonrandomized trial, observational studies, or registry studies, or meta-analysis of such studies
      • Level C-LD - randomized or nonrandomized studies with methodological limitations or meta-analyses of such studies
      • Level C-EO - consensus of expert opinion based on clinical experience
    • Reference - ACC/AHA/HRS guideline on evaluation and management of patients with syncope (J Am Coll Cardiol 2017 Aug 1;70(5):620OpenInNewfull-textOpenInNew)
  • European Society of Cardiology (ESC) grading system for recommendations
    • classes of recommendations
      • Class I - evidence and/or general agreement that treatment or procedure is beneficial, useful, effective
      • Class II - conflicting evidence and/or divergence of opinion about usefulness/efficacy of treatment or procedure
        • Class IIa - weight of evidence/opinion in favor of usefulness/efficacy
        • Class IIb - weight of usefulness/efficacy less well established by evidence/opinion
      • Class III - evidence or general agreement that given treatment or procedure is not useful/effective and may be harmful in some cases
    • levels of evidence
      • Level A - data from multiple randomized trials or meta-analyses
      • Level B - data from single randomized trial or large nonrandomized studies
      • Level C - expert consensus opinion and/or small studies, retrospective studies, or registries
    • Reference - ESC guideline on diagnosis and management of syncope (29562304Eur Heart J 2018 Jun 1;39(21):1883OpenInNewfull-textOpenInNew)

Synthesized Recommendation Grading System for DynaMed

  • DynaMed systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based MethodologyOpenInNew).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow DynaMed users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed (DM), we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE)OpenInNew to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed (DM) synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

Special acknowledgements

  • Saumya Das, MD, PhD (Assistant Professor of Medicine, Harvard Medical School; Physician in Cardiac Electrophysiology, Massachusetts General Hospital; Massachusetts, United States) has provided peer review.
  • Dr. Das declares no relevant financial conflicts of interest.
  • Allen Shaughnessy, PharmD, M Med Ed, FCCP (Professor of Family Medicine and Director of Master Teacher Fellowship, Tufts University Family Medicine Residency; Cambridge Health Alliance; Massachusetts, United States)
  • Dr. Shaughnessy declares no relevant financial conflicts of interest.
  • Peter Oettgen MD, FACC, FAHA, FACP (Editor in Chief; Cardiologist, Beth Israel Deaconess Medical Center; Associate Professor of Medicine, Harvard Medical School, Massachusetts, United States)
  • Dr. Oettgen declares no relevant financial conflicts of interest.
  • The American College of Physicians (Marjorie Lazoff, MD, FACP; ACP Deputy Editor, Clinical Decision Resource) provided review in a collaborative effort to ensure DynaMed provides the most valid and clinically relevant information in internal medicine.
  • Choosing Wisely Canada acknowledges dissemination of their recommendations through DynaMed Plus to reach the point of clinical decision-making.
  • The Canadian Society of Hospital Medicine provides review for the incorporation of Choosing Wisely Canada recommendations.
  • The Canadian Society of Internal Medicine provides review for the incorporation of Choosing Wisely Canada recommendations.
  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of DynaMed Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors are employees of DynaMed and oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T116050, Syncope - Approach to the Patient; [updated 2018 Nov 30, cited place cited date here]. Available from https://www.dynamed.com/topics/dmp~AN~T116050. Registration and login required.
  • KeyboardArrowRight

    Overview and Recommendations

    • Background

    • Evaluation

    • KeyboardArrowRight

      Management

      • Neurally mediated syncope

      • Orthostatic syncope

      • Cardiac syncope

  • Related Summaries

  • KeyboardArrowRight

    General Information

    • Description

    • Also called

    • Definitions

    • Types

  • KeyboardArrowRight

    Epidemiology

    • Incidence/Prevalence

    • Prevalence of syncope types

    • Risk factors

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    Differential Diagnosis

    • Causes of neurally mediated syncope

    • Causes of orthostatic syncope

    • Causes of cardiac syncope

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      Conditions that mimic syncope

      • Disorders with partial or complete loss of consciousness without global cerebral hypoperfusion

      • Disorders without impairment of consciousness

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      Differentiating seizure from syncope

      • Differentiating seizure from syncope

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    Evaluation

    • Algorithms

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      History and Physical

      • KeyboardArrowRight

        History

        • General history

        • Suggested etiologies of transient loss of consciousness (TLOC) based on triggers

        • Suggested etiologies of transient loss of consciousness (TLOC) based on onset of attack

        • Suggested etiologies of transient loss of consciousness (TLOC) based on witness account during event

        • Suggested etiology of transient loss of consciousness (TLOC) based on history after event

        • Suggested etiologies of transient loss of consciousness (TLOC) based on other features of history

        • Suggested etiologies of transient loss of consciousness (TLOC) based on past medical history

        • Suggested etiologies of transient loss of consciousness (TLOC) based on medication history

        • Suggested etiologies of transient loss of consciousness (TLOC) based on family history

        • History consistent with neurally mediated syncope

        • History consistent with orthostatic syncope

        • History consistent with cardiac syncope

        • History consistent with noncardiac cause of syncope

      • Physical

    • Electrocardiogram (ECG)

    • Laboratory testing

    • Clinical evaluation

    • Neurological evaluation

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    Syncope of Unknown Cause (Cryptogenic Syncope) after Initial Evaluation in Emergency Department

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      Risk Assessment

      • General information and recommendations from professional organizations

      • Factors associated with short-term serious outcomes and longer hospitalization

      • European Society of Cardiology (ESC) proposed risk stratification based on initial syncope evaluation

      • San Francisco Syncope Rule

      • Other risk models

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      Treatment setting

      • Recommendations (including indications for hospitalization)

      • Syncope management unit

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    Additional Testing and Treatment for Neurally Mediated Syncope

    • Tilt testing

    • Carotid sinus massage

    • Autonomic function tests

    • Treatment

  • Treatment for Orthostatic Syncope

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    Additional Testing and Treatment of Cardiac Syncope

    • Differentiating cardiac from non-cardiac syncope based on history and physical

    • KeyboardArrowRight

      Additional testing

      • Testing overview

      • Cardiac biomarkers

      • Echocardiography

      • KeyboardArrowRight

        Electrocardiography (ECG) monitoring

        • Indications and diagnostic criteria

        • In-hospital monitoring

        • Holter monitoring

        • Loop recorders (implantable and external)

      • Electrophysiological studies (EPS)

      • Exercise testing

    • KeyboardArrowRight

      Treatment of cardiac syncope

      • Syncope due to arrhythmias

      • Syncope secondary to structural cardiac or cardiovascular disease

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    Prognosis and Complications

    • Recurrence risk

    • Prognosis

    • Complications

  • KeyboardArrowRight

    Quality Improvement

    • Choosing Wisely

    • Choosing Wisely Australia

    • Choosing Wisely Canada

    • Choosing Wisely Italy

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    Guidelines and Resources

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      Guidelines

      • United States guidelines

      • United Kingdom guidelines

      • Canadian guidelines

      • European guidelines

    • Review articles

    • MEDLINE search

  • Patient Information

  • KeyboardArrowRight

    ICD Codes

    • ICD-10 codes

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    References

    • General references used

    • Recommendation grading systems used

    • Synthesized Recommendation Grading System for DynaMed

    • DynaMed Editorial Process

    • Special acknowledgements

    • How to cite

Topic Editor
Saumya Das MD, PhD
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Affiliations

Assistant Professor of Medicine, Harvard Medical School; Massachusetts, United States; Physician in Cardiac Electrophysiology, Massachusetts General Hospital; Massachusetts, United States

Conflicts of Interest

Dr. Das declares no relevant financial conflicts of interest.

Recommendations Editor
Allen Shaughnessy PharmD, M Med Ed, FCCP
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Affiliations

Professor of Family Medicine and Director of Master Teacher Fellowship, Tufts University; Massachusetts, United States

Conflicts of Interest

Dr. Shaughnessy declares no relevant financial conflicts of interest.

Deputy Editor
Peter Oettgen MD
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Affiliations

Editor in Chief, DynaMed; Cardiologist, Beth Israel Deaconess Medical Center; Massachusetts, United States; Associate Professor of Medicine, Harvard Medical School; Massachusetts, United States

Conflicts of Interest

Dr. Oettgen declares no relevant financial conflicts of interest.

Produced in collaboration with American College of Physicians

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Syncope Additional Evaluation and Diagnosis

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