Syncope

Dr. Seana Nelson PGY 5

Cardiology

Objectives

• Understand etiologies of syncope
• Review syncope work up
• Review management of cardiac syncope
  • Review manamgement of other forms of syncope
• Driving and Syncope

Key References

• Brignole, M., Moya, A., de Lange, F.J., Deharo, J.C., Elliott, P.M., Fanciulli, A., Fedorowski, A., Furlan, R., Kenny, R.A., Martín, A. and Probst, V., 2018. Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope. European heart journal, 39(21), pp.e43-e80.

• Sandhu, R.K., Raj, S.R., Thiruganasambandamoorthy, V., Kaul, P., Morillo, C.A., Krahn, A.D., Guzman, J.C., Sheldon, R.S., Banijamali, H.S., MacIntyre, C. and Manlucu, J., 2020. Canadian Cardiovascular Society clinical practice update on the assessment and management of syncope. Canadian Journal of Cardiology, 36(8), pp.1167-1177.
• Shen, W.K., Sheldon, R.S., Benditt, D.G., Cohen, M.I., Forman, D.E., Goldberger, Z.D., Grubb, B.P., Hamdan, M.H., Krahn, A.D., Link, M.S. and Olshansky, B., 2017. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Journal of the American College of Cardiology, 70(5), pp.e39-e110.

Syncope: Definition

Total loss of consciousness due to cerebral hypoperfusion.

Onset is rapid.

Duration is short.

Recovery is spontaneous and complete.

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Total loss of consciousness Definition

Loss of awareness =

amnesia for the period of loss of consciousness

+ unresponsive

Associated with abnormal motor control

Duration is short

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope Mechanism

Reduced blood flow for 6-8 seconds.

Reduced SBP 50-60 mmHg at the level of the heart or

 SBP 30-45 mmHg at the level of the brain

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Total loss of consciousness Differential 

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope Differential

Reflex Mediated

• Vasovagal
• Situational
• Carotid Sinus
• Non-classical forms

Orthostatic hypotension

• Drug-induced
• Volume depletion
• Primary autonomic (neurogenic)
• Secondary autonomic (neurogenic

Cardiac

• Bradycardia
• Tachycardia
• Structural
• Cardiopulmonary
• Great vessel (e.g. PE, dissection)

Syncope due to a reflex: Differential

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope due to Orthostatic Hypotension: Differential

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope due to Cardiac causes: Differential

Clinical Syncope Assessment

Key clinical features

• Was there actual loss of consciousness
• If loss of consciousness- was it syncopal or non-syncopal: historical clues 
• If syncope- is the cause clear?
• Is the patient high risk for cardiovascular events or death

Key clinical features

• Was there actual loss of consciousness
  • Short duration?
  • Loss of awareness and responsiveness?
• If loss of consciousness- was it syncopal or non-syncopal: historical clues 
• If syncope- is the cause clear?
• Is the patient high risk for cardiovascular events or death

Key clinical features

• Was there actual loss of consciousness
• If loss of consciousness- was it syncopal or non-syncopal? Some historical clues-
  • Features of the attack
  • The onset of the attack
  • Occurred during the attack or reported from bystanders
  • After the attack
• If syncope- is the cause clear?
• Is the patient high risk for cardiovascular events or death

Key clinical features

• Was there actual loss of consciousness
• If loss of consciousness- was it syncopal or non-syncopal
• If syncope- is the cause clear?
  • History & Physical (*include supine and standing BP)
  • ECG
  • Additional testing based on findings
• Is the patient high risk for cardiovascular events or death

Syncope: Key historical features

Reflex Syncope

• Long history, starting <40 yo
• After unpleasant sight, sound, smell
• Prolong standing
• During a meal
• In crowded, hot places
• Autonomic activation before: pallor, sweating, N/V
• No HD

Orthostatic hoTN

• While or after standing
• Prolonged standing
• Standing after exertion
• Post-prandial hypotension
• Temporal relationship with start/stop of related medication
• Autonomic neuropathy or PD

Cardiac

• During exercise
• Supine
• Sudden onset palpitations--> syncope
• FHx of sudden death at a young age
• Structural HD
• Coronary HD
• ECG findings

N/V = nausea and or vomiting; HD = heart disease;

PD = Parkinson's disease; FHx = family history

Key clinical features

• Was there actual loss of consciousness
• If loss of consciousness- was it syncopal or non-syncopal
• If syncope- is the cause clear?
• Is the patient high risk for cardiovascular events or death

Diagnostic Criteria

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope Risk

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope Risk

Sandhu et al. 2020 CCS Syncope Guidelines Clinical Practice Update

Syncope Risk: ECG

Sandhu et al. 2020 CCS Syncope Guidelines Clinical Practice Update

Syncope: Arrhythmic ECG features

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Syncope Decision Tool? 

• There are numerous tools, e.g. Canada Syncope Tool
• Outside of Canada perform no better than clinical judgement
• Features consistently associated with poor outcomes:
  • ​older age
  • heart disease
  • abnormal vital signs
  • abnormal ECG
  • abnormal lab values—
    • hemoglobin/hematocrit, troponin, or natriuretic peptides;
  • presumed etiology

To admit or not to admit?

Sandhu et al. 2020 CCS Syncope Guidelines Clinical Practice Update

Possible specific testing

• Carotid hypersensitivity
• Orthostatic Challenges:
  • Active standing
  • Tilt Testing
• Autonomic function testing
  • Valsalva manoeuvre
  • Deep breathing
  • 24-hour ambulatory blood pressure monitoring
• Arrhythmia monitoring
• Structural disease
  • Echocardiography
  • Stress echocardiography

**Persued based on clinical suspicion**

Tilt Table Testing

• Syncope triggered by prolonged standing.
  • Confirm reflex syncope diagnosis
  • Assessment of autonomic failure by initial evaluation
    • Postural orthostatic tachycardia syndrome
    • Delayed orthostatic hypotension

Specific testing: Arrhythmia monitoring

Specific testing:

Arrhythmia monitoring

Sandhu et al. 2020 CCS Syncope Guidelines Clinical Practice Update

Specific testing:

Arrhythmia monitoring

• Symptom rhythm correlation
• Finding of a significant rhythm:
  • Pause > 3 seconds
  • Rapid SVT (>160 bpm for >32 beats)
  • Ventricular tachycardia

Specific testing: EP Study

• In the broad population, there is limited use of EPS
  • Often etiology can be identified by rhythm monitoring
• Indications per ESC:
  • Asymptomatic sinus bradycardia (suspected sinus arrest)
  • Bifascicular bundle branch block- concern for impending high-degree AV block
  • Suspected tachycardia

Specific testing: EP Study Indications for PM

• Asymptomatic sinus bradycardia (suspected sinus arrest)
  • High pre-test probability
    • if sinus bradycardia HR < 50
    • Sinoatrial block
  • Prolong sinus node recovery time on EPS >1.6 or 2 seconds or >525 ms corrected
• Bifascicular bundle branch block- concern for impending high-degree AV block
• Suspected tachycardia

Specific testing: EP Study Indications for PM

• Asymptomatic sinus bradycardia (suspected sinus arrest)
• Bifascicular bundle branch block- concern for impending high-degree AV block
  • Prolonged His-Purkinje conduction time (HV interval) >70 ms
  • Induction of 2' or 3' AV block with procainamide or disopyramide
• Suspected tachycardia

Specific testing: EP Study Indications for PM/ICD

• Asymptomatic sinus bradycardia (suspected sinus arrest)
• Bifascicular bundle branch block- concern for impending high-degree AV block
• Suspected tachycardia
  • Induction of VT in patients with previous MI and Normal LVEF

Managemenent of Cardiac syncope

Cardiac pacing

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Cardiac pacing in SND

2018 ACC/AHA/HRS bradycardia and conduction guidelines

Cardiac pacing

2018 ACC/AHA/HRS Bradycardia and conduction delay guidelines

Cardiac syncope due to tachyarrhythmias

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

 Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope

Management of Syncope in structural heart disease

• ICD for low EF  following OMT >3 months,  if syncope occurs ICD can be considered or monitoring (ILR ) (ESC IIa)
• HCM patients should have ICD following syncope if HCM (2a AHA/ACC)
• ICD for ARVC with syncope, or ILR if low risk based on multiparametric analysis
• Long QT Syndrome with syncope: ICD + Beta-blockers
  • Left cardiac sympathetic denervation in symptomatic LQTS: beta-blockers not tolerated, ICD contraindicated, on beta-blockers and multiple ICD shocks
• Brugada Syndrome: ICD for type 1 ECG pattern and syncope

LQTS: Long QT Syndrome

Management of Non-Cardiac Syncope

Vasovagal syncope management

• Reassurance of benign nature
• Avoidance of triggers
• Lying down at the onset of pre-syncope symptoms
• Failure of non-pharmacologic treatment occurs in 15-20% 
  • Combination therapy is occasionally needed for patients with refractory VVS.
  • β-Blockers may be used in patients older than 42 years
  • Fludrocortisone (0.2 mg/d once a day) or midodrine (5-15 mg every 4 hours, 3 times a day)
• ​Pacemaker indications for vagal syncope: only if very symptomatic and other options have been exhausted.
  • Documented symptomatic asystole > 3 seconds or asymptomatic asystole > 6 seconds
  • Tilt-induced: asystole > 3 seconds or heart rate < 40 beats per minute for > 10 seconds.

Management of syncope from orthostatic hypotension

• Reassurance
• Salt + Water intake (if no contraindications)
• Discontinue offending medications
• Counter pressure manoeuvres, compression stockings
• Failure of non-pharmacologic interventions: 
  • Fludrocortisone
  • Midrodine

Syncope and Driving

Syncope and Driving

CMAJ 2017 Driver's guide 9th Ed.