01Approach to the Critical Patient/attcp45

Immediate stabilization

›Life threats requiring urgent action

›Hemodynamic instability

›SBP <90 mmHg

›HR <40 bpm or >150 bpm

›Altered mental status

›Active arrhythmia on monitor

›Sustained VT: synchronized cardioversion if pulseless or unstable

›VF or pulseless VT: immediate defibrillation per ACLS

›Complete heart block with hemodynamic compromise: transcutaneous pacing

›Syncope during exertion or while supine

›Highest risk for structural or arrhythmic cause

›Do not discharge without definitive monitoring

Monitoring and targets

›Monitoring bundle

›Continuous cardiac monitoring

›Detect arrhythmia onset or recurrence

›Telemetry >12 hours increases arrhythmia detection sensitivity

›12-lead ECG within 10 minutes of arrival

›Class I recommendation per ACC/AHA/HRS 2017 guidelines

›Identifies high-risk findings in up to 50% of cardiac syncope

›IV access established

›Two large-bore peripheral IVs

›Facilitates rapid medication delivery

›Pulse oximetry and blood pressure monitoring

›SBP target >90 mmHg

›SpO2 target >94%

›Escalation triggers

02History/hx68

Onset and prodrome

›Syncope characterization

›Sudden loss of consciousness without prodrome

›Strongly suggests cardiac etiology

›Brief palpitations as only warning also suggests arrhythmia

›Prolonged prodrome

›Nausea, warmth, diaphoresis favor vasovagal

›Argues against cardiac cause

›Duration of unconsciousness

›Typically brief in cardiac syncope

›Prolonged confusion post-event suggests seizure

›Activity at time of event

›Syncope during exertion

›Highly concerning for structural or arrhythmic cardiac cause

›Distinguishes from post-exertional vasovagal pattern

›Syncope while supine or at rest

›High likelihood ratio for cardiac cause

›Rules against orthostatic or vasovagal mechanism

Alarm features in history

›High-risk historical clues

›Chest pain or dyspnea immediately preceding event

›Suggests ACS, PE, or structural cause

›Requires troponin and ECG at minimum

›Palpitations immediately before loss of consciousness

›Arrhythmic etiology most likely

›Captures tachyarrhythmia or rapid rate change

›Witnessed cyanosis during episode

›Likelihood ratio 6.2 for cardiac syncope

03Physical Exam/exam50

Vital signs

›Hemodynamic snapshot

›Heart rate and rhythm

›Bradycardia below 50 bpm

›Tachycardia above 100 bpm

›Irregularity suggesting AF

›Blood pressure

›SBP below 90 mmHg high-risk finding

›Orthostatic measurements: supine then 1 and 3 minutes upright

›Drop >20 mmHg systolic or >10 mmHg diastolic with symptoms

›Oxygen saturation

›Hypoxia below 94% suggests PE or cardiopulmonary cause

›Normal SpO2 does not exclude cardiac etiology

›Temperature

›Fever points toward infectious trigger of arrhythmia

Cardiovascular exam

›Cardiac auscultation

›Aortic stenosis findings

›Harsh crescendo-decrescendo systolic murmur at right upper sternal border

›Radiation to carotids

›Delayed and diminished carotid upstroke

›Hypertrophic cardiomyopathy findings

›Dynamic outflow murmur that increases with Valsalva

›S4 gallop

›Signs of heart failure

›S3 gallop

›Elevated JVP

›Pulmonary rales

04Differential Diagnosis/ddx62

Life-threatening cardiac causes

›Arrhythmic etiologies

›Ventricular tachycardia

›ICD-10 I47.2

›Most dangerous especially with underlying structural disease

›Ventricular fibrillation

›ICD-10 I49.01

›Often presents as resuscitated cardiac arrest

›High-grade AV block

›Mobitz type II and complete heart block

›ICD-10 I44.1 and I44.2

›Sinus pauses greater than 3 seconds

›Sick sinus syndrome

›ICD-10 I49.5

›Tachycardia-bradycardia syndrome

›Channelopathies

›Long QT syndrome ICD-10 I45.81

›Brugada syndrome ICD-10 I49.8

›CPVT catecholaminergic polymorphic VT

›WPW with rapid accessory pathway conduction

›Structural cardiac causes

›Severe aortic stenosis

›ICD-10 I35.0

›Classic exertional syncope in elderly

›Hypertrophic cardiomyopathy

›ICD-10 I42.1

›Exertional syncope in young patients with family history of SCD

›Acute MI or ischemia

05Laboratory Tests/lt49

Core emergency labs

›Cardiac biomarkers

›Troponin I or T

›High-sensitivity troponin at 0 and 1 or 2 hours

›Elevation indicates ACS as syncope etiology

›Part of high-risk stratification panel

›BNP or NT-proBNP

›Elevation suggests underlying cardiomyopathy or HF

›Supports admission decision in intermediate-risk patients

›Electrolytes and metabolic panel

›Potassium

›Hypokalemia increases arrhythmia risk

›Maintain K above 4.0 mmol/l in QT-prolonging drug users

›Magnesium

›Hypomagnesemia precipitates torsades de pointes

›Target Mg above 0.8 mmol/l in at-risk patients

›Calcium and sodium

›Hypocalcemia prolongs QT interval

›Hyponatremia as trigger for neurological mimics

›Renal function

›CKD alters electrolyte handling and drug clearance

›Creatinine and eGFR for dosing adjustments

›Complete blood count

›Hemoglobin

›Anemia-related low-output state

›GI bleed as hemorrhagic cause of syncope

›WBC

›Infection or myocarditis as arrhythmia trigger

06Diagnostic Tests/dt133

Scoring Systems

›Canadian Syncope Risk Score

›Predisposing conditions

›Vasovagal predisposition: -1 point

›Heart disease history: 1 point

›Symptoms and signs

›Systolic BP below 90 or above 180 at any time: 2 points

›Elevated troponin above 99th percentile: 2 points

›Abnormal QRS axis: 1 point

›QRS duration above 130 ms: 1 point

›QTc above 480 ms: 2 points

›Emergency physician diagnosis of vasovagal: -2 points

›Emergency physician diagnosis of cardiac: 2 points

›Score interpretation

›Very low score less than -2: 0.4% 30-day serious outcome

›Low score -2 to 0: less than 1% 30-day serious outcome; safe discharge

›Medium score 1 to 3: 4 to 5% 30-day serious outcome; observation reasonable

›High score above 3: 14 to 20% 30-day serious outcome; admission indicated

›Multicenter validation

›JAMA Internal Medicine 2020 multicenter ED validation

›Performs well across broad ED syncope populations

›FAINT Score

›Components for patients 40 years or older

›FEV1 reduced

›AF or flutter history

›Ischemia prior

›NT-proBNP elevated

›Troponin elevated

›Performance

›FAINT score 0: 96.7% sensitivity and 98.8% NPV for serious cardiac outcome

›2026 JAMA Network Open US validation study

›San Francisco Syncope Rule

›Five criteria

›Abnormal ECG

›Hematocrit below 30%

›CHF history

›Shortness of breath

›SBP below 90 mmHg

›Performance

›Sensitivity 87% for serious outcomes

›Limited specificity reduces utility for discharge decisions

›Risk stratification framework

›High-risk features requiring admission

›Any high-risk ECG finding

›Known structural heart disease

›SBP below 90 mmHg on presentation

›Syncope during exertion or while supine

›Family history of SCD under age 50

›Elevated troponin or BNP

›2017 ACC/AHA/HRS guidelines Class I admission indications

›Serious medical condition potentially relevant to syncope identified

›Documented arrhythmia as cause requiring treatment

›Syncope with hemodynamic instability or significant injury

Scoring Systems for arrhythmia detection

›ECG high-risk pattern recognition

›AV block findings

›Mobitz type II: dropped QRS after fixed PR; high risk, pacing required

›Third-degree AV block: complete dissociation of P and QRS

›Alternating LBBB and RBBB: severe conduction system disease

›Channelopathy patterns

›Brugada Type 1: coved ST elevation V1-V2 with inverted T waves

›Long QT: QTc above 470 ms in males or above 480 ms in females

›Epsilon waves and T-wave inversions V1 to V3 suggest ARVC

›Short PR with delta wave indicates WPW

›Ischemia and LV pathology

›Q waves or acute ST changes indicate ACS

›LVH voltage criteria suggests HCM or hypertensive disease

›Bifascicular block carries risk of intermittent complete heart block

›Bradycardia findings

›Sinus bradycardia below 40 bpm

›Sinus pauses greater than 3 seconds indicating sick sinus syndrome

MRI

›Cardiac MRI indications

›Structural and myocardial assessment

›Evaluation for HCM, ARVC, or non-ischemic cardiomyopathy

›Late gadolinium enhancement for fibrosis and scar mapping

›Assessment of LVEF and regional wall motion abnormalities

›ARVC diagnosis

›RV morphology, fat infiltration, and regional dysfunction

›Task force criteria support for ARVC diagnosis

›Sensitivity for ARVC higher than echocardiography

›When to use

›Unexplained syncope with normal or non-diagnostic echo

›Suspected myocarditis or infiltrative cardiomyopathy

›Family history of channelopathy or SCD without clear diagnosis

›Limitations

›Limited availability in acute ED setting

›Pacemaker or ICD may be contraindication

›Requires stable patient and expertise in interpretation

CT

›CT coronary angiography

›Indications

›Suspected coronary artery disease as syncope trigger

›Low to intermediate pretest probability for obstructive CAD

›Radiation and contrast exposure considerations

›Performance

›High sensitivity and specificity for obstructive CAD

›Useful when functional stress testing not feasible

›Limitations

›Does not assess arrhythmia substrate

›Requires beta-blockade for optimal image quality

›CT pulmonary angiography

›Indications

›Syncope with suspected massive PE

›Tachycardia, hypoxia, and pleuritic chest pain constellation

›Use Wells or Geneva score to guide ordering

›Performance

›Near 100% sensitivity for central PE when performed correctly

›Negative predictive value sufficient to exclude PE in intermediate-low risk

›CT aorta

›Indications

›Syncope with tearing chest or back pain

›Pulse or blood pressure asymmetry between limbs

›Suspected aortic dissection or aortic aneurysm

›Sensitivity and specificity near 100% for Type A and B aortic dissection

Ultrasound

›Point-of-care echocardiography

›Immediate structural assessment

›LVEF and global systolic function

›RV size and function for PE assessment

›Pericardial effusion and tamponade physiology

›Valvular assessment

›Aortic valve calcification and stenosis gradient estimation

›Mitral valve pathology

›IVC assessment

›Collapsibility index for volume status

›Plethoric IVC in tamponade or RV failure

›Formal echocardiography

›Indications

›All patients with unexplained syncope and suspected structural disease

›Assessment of LVEF for ICD decision-making

›Doppler gradients across aortic or mitral valve

›Performance

›LVEF under 35% identifies high-risk ICD candidates

›Severe AS peak gradient above 40 mmHg confirms critical stenosis

›Limitations

›Does not capture paroxysmal arrhythmias

›Acoustic windows limited in obese or COPD patients

07Disposition/dispo50

Admission indications

›High-risk: admit for monitoring and treatment

›Documented arrhythmia causing syncope

›Class I ACC/AHA/HRS 2017 recommendation

›Telemetry monitoring while awaiting definitive therapy

›Syncope with hemodynamic instability at presentation

›ICU or high-dependency unit placement

›Continuous arterial line monitoring for unstable patients

›Significant injury from syncopal fall

›Head injury requiring CT

›Fractures requiring orthopedic management

›Abnormal ECG with high-risk pattern

›New bundle branch block or Mobitz II or complete heart block

›Active ischemic changes

›Known structural heart disease with any syncope

›Class IIa: observation with expedited cardiac testing reasonable

›LVEF below 35% requires ICD evaluation before discharge

›Intermediate-risk: structured ED observation

›Observation unit protocol

›Telemetry monitoring minimum 6 to 12 hours

›Serial ECGs and troponin measurements

›Cardiology consultation from observation unit

›Criteria for successful observation discharge

›No arrhythmia detected on monitoring

›Serial troponin negative

›Stable ECG without new high-risk findings

Discharge criteria

›Low-risk safe discharge criteria

08Treatment/t78

Immediate arrhythmia management

›Ventricular fibrillation and pulseless VT

›Defibrillation

›Biphasic 200 J initial shock

›CPR 2 minutes between shocks

›Epinephrine 1 mg IV every 3 to 5 minutes

›Amiodarone 300 mg IV bolus after third shock

›Repeat 150 mg IV bolus if refractory VF

›Sustained VT with pulse and hemodynamic compromise

›Synchronized cardioversion

›100 to 200 J biphasic initial

›Conscious sedation with midazolam 1 to 2 mg IV or propofol 0.5 to 1 mg/kg

›Stable VT: antiarrhythmic options

›Amiodarone 150 mg IV over 10 minutes loading dose

›Followed by 1 mg/min infusion for 6 hours

›Then 0.5 mg/min for 18 hours

›Procainamide 20 to 50 mg/min IV until arrhythmia suppressed

›Maximum loading dose 17 mg/kg

›Maintenance 1 to 4 mg/min infusion

›Bradyarrhythmia management

›Atropine 0.5 mg IV for symptomatic sinus bradycardia or AV block

›Repeat every 3 to 5 minutes to maximum 3 mg total

›Ineffective below the AV node

›Transcutaneous pacing

›For symptomatic complete heart block or Mobitz II not responding to atropine

›Rate 60 to 80 bpm initial setting

›Output 50 to 100 mA starting, titrate to capture

›Transvenous pacing

›Bridge to permanent pacemaker implantation

›Preferred over transcutaneous for sustained pacing requirement

Reversible cause correction

›Electrolyte repletion

›Potassium repletion

›Target K above 4.0 mmol/l in arrhythmia risk patients

›IV KCl 10 to 20 mmol/hour via central or large peripheral line

›Oral supplementation if mild depletion and tolerating PO

›Magnesium repletion

›Target Mg above 0.8 mmol/l

›IV MgSO4 2 g over 10 to 15 minutes for torsades de pointes

›Repeat 2 g dose if torsades persists

›Torsades de pointes management

›IV MgSO4 2 g IV bolus first-line regardless of Mg level

›Overdrive pacing at rate 90 to 100 bpm to shorten QT

›Discontinue all QT-prolonging medications

›Volume resuscitation

›IV crystalloid 500 mL bolus for volume-depleted patients

›Reassess hemodynamics after each bolus

›Avoid excess volume in suspected cardiogenic cause

Definitive and device therapy

›Permanent pacemaker implantation

›Indications

›Symptomatic sinus node dysfunction: Class I recommendation

›High-grade AV block (Mobitz II or complete): Class I recommendation

›Syncope with documented pause greater than 3 seconds

›Dual-chamber pacing preferred for AV block

›Maintains AV synchrony

›Reduces pacemaker syndrome

›ICD implantation

›Indications

›Unexplained syncope with LVEF below 35% and NYHA class II-III: Class I

›Unexplained syncope with structural disease and inducible sustained VT on EPS: Class I

›Unexplained syncope with non-ischemic DCM and significant LV dysfunction: Class IIa

›High-risk Brugada or LQTS refractory to beta-blocker: Class I

›Catheter ablation

›SVT including AVNRT, AVRT, WPW: often curative

›VT ablation for recurrent VT post-ICD shocks

›CPVT in selected patients

›Medical therapy by etiology

›Channelopathy treatment

›LQTS: beta-blocker nadolol or propranolol

›Nadolol 40 to 80 mg daily

›Avoid QT-prolonging medications

›CPVT: beta-blocker nadolol or flecainide adjunct

›Flecainide 100 to 150 mg twice daily as adjunct

›Brugada: ICD for high risk; quinidine or isoproterenol for electrical storm

›Structural cardiomyopathy

›Guideline-directed medical therapy for underlying HF

›ACE inhibitor or ARNI for HFrEF

›Beta-blocker: carvedilol or metoprolol succinate

›MRA: spironolactone or eplerenone

›SGLT2 inhibitor: dapagliflozin or empagliflozin

09Special Populations/sp82

Pregnancy

›Cardiac syncope in pregnancy

›Physiologic changes affecting assessment

›Increased plasma volume and cardiac output by 40 to 50%

›Physiologic tachycardia and reduced SVR

›Supine hypotension syndrome from IVC compression by gravid uterus

›Causes specific to or more common in pregnancy

›Peripartum cardiomyopathy presenting with syncope

›LVEF below 45% with new HF in late pregnancy or post-partum

›PE risk 5-fold higher in pregnancy; highest risk post-partum

›ECG changes in normal pregnancy

›Left axis deviation from diaphragm elevation

›ST-T wave changes are non-specific

›Do not omit ECG: benefits outweigh fetal radiation risk

›Management considerations in pregnancy

›Radiation minimization

›Echo preferred over CT when possible for structural assessment

›Use CT-PA for definitive PE exclusion when clinical probability high

›Fetal shielding for abdominal CT

›Medication safety

›Adenosine safe for SVT conversion in pregnancy

›Amiodarone: avoid if possible due to fetal thyroid toxicity

›Beta-blockers: use with awareness of IUGR risk but generally safe

›Cardioversion safe in any trimester: no evidence of fetal harm

›Consult

›Maternal-fetal medicine and cardiology co-management

›Delivery planning for peripartum cardiomyopathy

Geriatric

›Age-related risk elevation

›Highest incidence of cardiac syncope in patients over 60 years

›Male sex additional demographic risk factor

›Atrial fibrillation prevalence increases with age

›Multifactorial syncope common in older adults

›Orthostatic hypotension plus arrhythmia plus polypharmacy interaction

›Frailty and autonomic dysfunction lower threshold for syncope

›Assessment modifications

›Polypharmacy review

›QT-prolonging drug burden assessment

›Anticholinergic burden contributing to orthostasis

›Diuretic and antihypertensive combinations causing volume depletion

›Atypical presentations

›Syncope presenting as unexplained fall without witnessed LOC

›Retrograde amnesia for prodrome common

›Higher injury severity from syncope due to osteoporosis

›Treatment considerations

›Rate and dose adjustment

›Reduced renal clearance alters antiarrhythmic drug levels

›Start low go slow principle for antiarrhythmics

›Pacemaker outcomes

›Excellent outcomes for AV block and sick sinus syndrome at any age

›Physiological pacing preferred to reduce pacing-induced cardiomyopathy

›Falls risk mitigation

›Occupational therapy and physiotherapy for discharge planning

›Medication reconciliation before discharge

Pediatrics

›Cardiac syncope in children and adolescents

›Epidemiology

›Cardiac syncope in children accounts for 15 to 25% of pediatric syncope

›Vasovagal most common overall but cardiac carries highest mortality

›Peak presentation in adolescence during growth and sports activity

›Structural causes in young patients

›HCM most common structural cause of SCD in young athletes

›Congenital long QT syndrome presenting in childhood

›ARVC more commonly presents in adolescence or early adulthood

›Congenital coronary anomalies causing exertional syncope

›Red flags in pediatric syncope

›Exertional syncope

›Highest risk: evaluate urgently for structural disease

›Screen with ECG and echocardiography

›Family history triggers

›Family history of SCD under age 40 mandates urgent evaluation

›Screening of first-degree relatives for channelopathies

›ECG findings in pediatric patients

›Congenital LQTS: QTc above 460 ms in children

›WPW pattern with short PR and delta wave

›Brugada: rare before puberty but screen family members

›Management in pediatrics

›Drug dosing

›Adenosine 0.1 mg/kg IV for SVT, maximum 6 mg first dose

›Repeat 0.2 mg/kg, maximum 12 mg second dose

›Beta-blockers for LQTS: propranolol 2 to 4 mg/kg/day divided

›Cardiology referral

›Pediatric cardiology for all unexplained syncope in children

›Sports restriction pending evaluation for exertional syncope

›Genetic testing for suspected channelopathy and family screening

10Background/b74

Epidemiology

›Incidence and prevalence

›Syncope accounts for 1 to 3% of all ED visits

›Cardiac syncope comprises 5 to 21% of ED syncope presentations

›Approximately 10% of ED syncope patients have serious underlying cardiac condition

›Mortality burden

›1-year mortality 2 to 5 times higher than noncardiac syncope

›Annual mortality up to 30% in patients with structural heart disease and syncope

›Short-term mortality highest in first 7 days after presentation

›Demographics

›Age above 60 strongest demographic predictor of cardiac etiology

›Male sex independently associated with cardiac syncope

›Age at first episode above 35 has likelihood ratio 3.3 for cardiac etiology

›Population distributions

›Arrhythmic versus structural breakdown

›Arrhythmias account for 50 to 60% of cardiac syncope causes

›Structural disease accounts for remainder

›Device therapy prevalence

›1 to 2% of ED syncope patients require pacemaker or ICD during index visit

›Up to 5% implanted within 30 days of presentation

Pathophysiology

›Mechanism of consciousness loss

›Final common pathway

›Global cerebral hypoperfusion causing loss of postural tone and consciousness

›CBF reduction below 35 ml per 100g per minute for 6 to 8 seconds

›Cardiac output reduction is the primary mechanism in cardiac syncope

›Arrhythmic mechanisms

›Tachyarrhythmia: rate too fast for adequate ventricular filling and output

›Bradyarrhythmia: rate too slow for cardiac output maintenance

›Both cause sudden reduction in forward flow

›Structural mechanisms

›Fixed outflow obstruction: AS or HCM causing inadequate output with demand

›Exertional vasodilation without ability to augment output precipitates syncope

›Ischemia: acute wall motion abnormality or arrhythmia from ischemia

›Channelopathy mechanisms

›Long QT syndrome

›Delayed repolarization from abnormal ion channel function

›Early afterdepolarizations triggering torsades de pointes

›Torsades causing rapid VT with hemodynamic compromise

›Brugada syndrome

›SCN5A mutation in 20 to 30% of cases

›Phase 2 reentry causing VF predominantly during sleep or rest

›Exaggerated by fever, sodium channel blockers, and vagal tone

›CPVT

›RYR2 mutation causing calcium overload in cardiomyocytes

›Triggered by catecholamine surge during exercise or emotion

›Bidirectional or polymorphic VT on exercise testing

›Autonomic contributions

›Reflex arc in vasovagal differs from cardiac syncope

›Cardiac syncope lacks the vagal bradycardia-vasodilation reflex

›Primary cardiac output failure distinguishes from reflex syncope

Therapeutic Considerations

›Risk stratification guides therapy

›ICD decision framework

›LVEF is the most important single predictor of arrhythmia risk

›LVEF below 35% threshold for primary prevention ICD in ischemic cardiomyopathy

›Syncope with structural disease lowers threshold for ICD consideration

›Electrophysiology study role

›Inducible sustained VT or VF on EPS guides ICD implantation

›Negative EPS has high NPV for subsequent spontaneous VT

›Most useful in ischemic cardiomyopathy

›Drug-induced arrhythmia prevention

›QT surveillance in at-risk patients

›Baseline and follow-up QTc monitoring for patients on QT-prolonging drugs

›Combination of two or more QT-prolonging agents dramatically increases risk

›crediblemeds.org resource for updated QT-prolonging drug lists

›Electrolyte targets in arrhythmia prevention

›K above 4.0 mmol/l and Mg above 0.8 mmol/l for at-risk patients

›AHA scientific statement 2020 recommendation

›Evidence base for monitoring technology

›Ambulatory monitoring duration

›15-day monitoring superior sensitivity to 7-day for arrhythmia detection

›Implantable loop recorder for unexplained syncope up to 3 years monitoring

›ILR diagnostic yield 35 to 55% at 2 years in unexplained syncope

›Tilt table testing limitations

›Primarily for reflex syncope evaluation; not for cardiac arrhythmia workup

›Limited sensitivity and specificity in older populations

11Patient Discharge Instructions/pdi31

copy discharge instructions

›Discharge instructions for Syncope (Cardiac)

›What happened today

›You passed out because your heart temporarily beat too fast, too slow, or had an electrical problem

›We ran tests including ECG, blood tests, and monitored your heart rhythm

›The cause may not be fully identified yet and further testing is needed

›Driving restrictions

›Do not drive until your doctor tells you it is safe

›Driving restrictions depend on the cause and your local laws

›Ask your doctor specifically about return to driving

›Activity restrictions

›Avoid operating heavy machinery until cause is identified and treated

›Avoid swimming or working at heights alone until cleared

›Avoid strenuous exercise if the episode occurred during activity

›Medications

›Take all heart medications exactly as prescribed

›Do not stop any medications without speaking to your doctor first

›Avoid medications that can affect heart rhythm unless your doctor approves

›Return to the emergency department immediately for

›Another episode of fainting or near-fainting

›Chest pain or chest tightness

›Shortness of breath at rest or with minimal exertion

›Heart racing, pounding, or irregular rhythm that you feel

›New weakness, numbness, or difficulty speaking

›Dizziness that does not resolve on sitting or lying down

›Follow-up

›Follow up with your cardiologist or family doctor within 1 to 2 weeks

›You may need additional heart monitoring such as a Holter monitor or loop recorder

12References/r33

Guidelines and key sources

›Primary guidelines

›2017 ACC/AHA/HRS Guideline for Evaluation and Management of Syncope

›Shen WK, Sheldon RS, Benditt DG, et al. J Am Coll Cardiol. 2017

›Class I: ECG in all syncope patients

›Class I: Admission for documented arrhythmia, hemodynamic instability, or significant injury

›2017 AHA/ACC/HRS Guideline for Management of Ventricular Arrhythmias and Prevention of Sudden Cardiac Death

›Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. J Am Coll Cardiol. 2018

›AHA/ACCF Scientific Statement on Evaluation of Syncope 2006

›Strickberger SA, Benson DW, Biaggioni I, et al. J Am Coll Cardiol. 2006

›Key clinical studies

›Canadian Syncope Risk Score validation

›Thiruganasambandamoorthy V, et al. JAMA Internal Medicine. 2020

›Multicenter ED validation; robust risk stratification tool

›FAINT score validation

›Suh EH, Winskill C, Sacco DL, et al. JAMA Network Open. 2026

›96.7% sensitivity for serious cardiac outcome at FAINT score 0

›San Francisco Syncope Rule systematic review

›Wakai A, Sinert R, Zehtabchi S, et al. Academic Emergency Medicine. 2025

›Did this patient have cardiac syncope: Rational Clinical Examination

›Albassam OT, Redelmeier RJ, Shadowitz S, et al. JAMA. 2019

›Likelihood ratios for history and exam features

›Syncope Evaluation and Differential Diagnosis

›Bayard M, Gerayli F, Holt J. American Family Physician. 2023

›Drug-Induced Arrhythmias AHA Scientific Statement

›Tisdale JE, Chung MK, Campbell KB, et al. Circulation. 2020

›Canadian Syncope Risk Score practice recommendations

›Hudek N, Brehaut JC, Rowe BH, et al. CJEM. 2023

Evidence & Review