Syncope

1. What is Syncope?

2. High Risk Features?

3. 3 Common Causes

What is Syncope?

• “a transient, self-limited loss of consciousness due to acute global impairment of cerebral blood flow. The onset is rapid, duration brief, and recovery spontaneous and complete”

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High Risk Features

• History of  angina chest pain, 

• EKG features of ischemia

• Features of:

  • Heart Failure, 

  • valvular disease

  • other structural heart defect or disease

• EKG Evidence of:

  • Long QT interval, 

  • heart block, 

  • interventricular conduction delay with QRS complex >120ms, 

  • atrial fibrillation, 

  • ventricular arrythmias, 

  • Non- sustained ventricular tachycardia or pre-excitation syndrome\

  • evidence of Brugada pattern

• Family History of Sudden Death

• Palpitations at the time of the syncopal event

• Syncope during exercise or at rest

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• 3 common causes

  • Neurally Mediated Syncope

  • Orthostatic Mediated Syncope

  • Cardiac Syncope

List out the Ddx for syncope

Describe Neurally Mediated Syncope

• MOA

• Common Causes?

  • Vasovagal

  • Situational reflex

    • Pulmonary

    • Urogenital

    • GI

    • Cardiac

    • Carotid Sinus

    • Ocular

• Clinical features

  • Biggest difference from seizures?

• Tx

MOA:

• sudden, transient change in autonomic activity ->

  • Increased para outflow + sympathetic inhibition ->

    • Bradycardia + vasodilation + reduced vasoconstrictor tone ->

      • BP fall result in reduced cerebral blood flow 

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Common Causes

• Vasovagal Syncope

  • intense emotion + unpleasant sights/odors

• Situational Reflex Syncope

  • Pulmonary- 

    • Cough syncope, 

    • wind instrument players’ syncope, 

    • Weightlifters syncope, 

    • “the fainting game”, 

    • sneeze syncope, 

    • airway instrumentation

  • Urogenital- 

    • Post-micturition syncope, 

    • GU tract instrumentation, 

    • prostatic massage

  • GI- 

    • Swallow syncope, 

    • glossopharyngeal neuralgia, 

    • esophageal stimulation, 

    • GI tract instrumentation, 

    • rectal examination, 

    • defecation

  • Cardiac

    • Bezold-Jarisch reflex, 

    • cardiac outflow obstruction

  • Carotid Sinus

    • Carotid sinus sensitivity, 

    • carotid sinus massage

  • Ocular

    • Increased ocular pressure (usually sudden), 

    • ocular surgery

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Clinical Features

• Autonomic Activation

  • Diaphoresis, pallor, palpitations, nausea, hyperventilation and yawning.

• Myoclonic Movements/Jerks

  • multifocal + arrhythmic.

• Eyes:

  • open + deviate up . 

  • Mydriasis 

  • Roving eye movements

• Incontinence

  • Urinary possible; fecal rare

• Confusion:

  • Resolves quickly

    • ***Biggest differentiator from seizure!***

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Tx:

• Reassurance

• Avoidance of provocative stimuli

• Increase intravascular volume 

• Acutely- Isometric counter-pressure maneuvers of limbs

  • Knees to chest or legs elevation 

  • Pre-syncope: teach pts to cross legs, or handgrip and flex arms

NOTE:

• Family history of 1st degree relative with similar symptoms is risk factor

Describe Orthostatic Mediated Syncope

• MOA

• 2 Main Categories/Causes

• Other Causes

• Clinical features

• Tx

MOA:

• -> Systolic/Diastolic  Reduction w/in 3 min of standing/head-up tilt 

  • Systolic: at least 20mm Hg 

  • Diastolic: at least 10mm Hg  

• -> no compensatory (or not enough) HR increase despite hypotension 

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2 Main Categories

• Primary Autonomic Failure

  • Lewy body diseases

    • Parkinson’s, Lewy body dementia, pure autonomic failure

  • Multiple system Atrophy

• Secondary Autonomic Failure due to Autonomic Peripheral Neuropathies

  • Diabetes

  • Amyloidosis

  • Hereditary sensory and autonomic neuropathies

  • Idiopathic immune-mediated autonomic neuropathy

  • Sjogren’s Syndrome

  • Paraneoplastic autonomic neuropathy

  • HIV Neuropathy

• Other Causes:

  • Postprandial hypotension

  • Iatrogenic/ Drug Induced

  • Volume Depletion

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Clinical Features

• Autonomic Failure! (usually)

• Light-headedness, Dizziness

• Vision problems

  • Blurring, Blacking out, seeing stars, tunnel vision

• Coat Hanger Headache 

  • (sub-occipital, posterior neck and posterior shoulder pain)

• Supine Hypertension 

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Tx

• Stop offending agents (medications)

• Control underlying disease

• Education 

• Increasing salt in meals

• Elevating head of bed -> avoid supine hypertension

• Medications if above fail

  • Fludrocortisone, midodrine, dihydroxyphenylserine and pseudoephedrine

  • 2nd line include pyridostigimine, yohimbine, desmopressin (DDAVP) and erythropoietin

Describe Cardiac Syncope

• MOA

• Common Causes

• Clinical Features

• Tx

MOA:

• Arrhythmias and/or structural heart disease 

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Common Causes

• Arrhythmias

  • Sinus Node Dysfunction

  • AV Node Dysfunction

  • Supraventricular Tachycardias

  • Inherited Channelopathies

• Cardiac Structural Disease

  • Valvular Disease

  • Obstructive Cardiomyopathies

  • Atrial Myxoma

  • Pericardial Effusions or Tamponade

  • Other Cardiomyopathies

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Clinical Features

• History of:

  • arrhythmia or known structural heart disease

  • palpitations or chest pain associated with syncope

• Suspect Meds + EKGs + Echocardiogram

NOTE:

• usually takes a Ventricular Heart Rate above 200 or below 40 to cause syncope

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Tx:

• Depends on ID of underlying patho; EX:

  • Vagal Maneuvers

  • Medication- Beta Blockers and Antiarrhythmic medications

  • Cardioversion

  • Valve Replacement

  • Cardiac Surgery

  • Cardiac Ablation

  • Implanted Cardioversion and Pacemaker devices