Syncope

Table Of Contents
1 Syncope
2 Presyncope
3 Clinical
4 Types of Syncope
5 Orthostatic Hypotension
6 Neurological Syncope
7 Cardiac Related Syncope
8 Cardiopulmonary Syncope
9 Dysthymias Syncope

Syncope

  • Brief loss of consciousness with the inability to maintain postural tone 
  • Spontaneously resolves without medical intervention 
  • Accounts for 1-2% of ED visits 
  • Accounts for 6% of hospital admissions 

Presyncope

  • Feeling of imminent fainting without LOC
  • Same physiologic process as syncope 

Clinical

  • History:
    • Details of preceding events – Witnesses?
    • Prodromal symptoms 
    • Duration of LOC
    • Symptoms occurring after return of consciousness 
    • Previous illnesses, alcohol, or drug use
    • PMH
    • Prior Hx of syncope
    • Medications 
  • Physical Exam:
    • Cardio: Murmurs 
    • Neuro: Focal neuro deficits 
    • Rectal: r/o GI bleeding 
    • Orthostatic BP – lying, standing, sitting 

Types of Syncope

PresentationCausesDiagnoseTreatment
Arrhythmia sudden with no prodrome arrhythmia EKG
24 hr Holter monitor or
event recorder		 Arrhythmia specific
Mechanical Cardiac Excersional Valve issue Echo Valve lesion – dependent
Neurogenic No prodrome, sudden, + focal neuronal deficit Posterior circulation Carotid U/S, CT angiogram Vascular disease
Orthostatic OrthostaticVolume decreased
(4D’s” diarrhea, dehydration, diuresis, and hemorrhage);
AMS = DM,
Parkinson’s age		 Systolic change of 20
Diastolic change of 10
HR change of 15		 Fluid resolves intravascular volume depletion
Vasovagal Visceral organ stimulation => cough, sit down to pee

Carotid bodies => boxers hit under the jaw, tight ties

Psychogenic => sight of blood		Situational, reproducible, and + prodrome beta-blockers

Orthostatic Hypotension

  • MOA:

    • When moving to an upright position –> gravity shifts blood to lower extremities –> Sympathetic nervous system increase output and decreases parasympathetic output –> HR increases + SVR increases –> Increase in CO and BP

    • If the autonomic compensatory response is insufficient –> decreased cerebal blood blood flow –> syncope 

  • Path: 
    • Ten second disruption of blood flow to cerebral cortices or to the brainstem, OR
    • Reduction in cerebral perfusion by 35-50%
  • Common Causes:
    • Intravascular volume loss 
    • Poor vascular tone caused by alpha receptor disorders 
    • Medications 
      • Erectile dysfx drugs
      • Anti-HTNs
      • Beta Blockers
      • Diuretics
      • Anti-dysrhythmics
      • Anti-psychotics 
      • Antidepressants
      • Antiparkinsonism drugs 
      • Nitrates
      • ETOH
      • Cocaine 

Neurological Syncope

  • Types: 
    • Vasovagal 
      • MOA: Associated with inappropriate vasodilation + bradycardia –> results in decreased vagal or sympathetic tone 
      • Triggers: prolonged standing or emotional distress, painful stimuli
      • Prodrome symptoms: 
        • Lightheadedness 
        • +/- N/V
        • Pallor 
        • Diaphoresis 
        • Feelings of warmth
      • Common Causes:
        • Exposure to unexpected or unpleasant stimuli 
        • – Sight, sound, smell
        • – Fear
        • – Pain
        • – Emotional distress 
        • – Instrumentation 
        • Reflex Mediated Syncope – Prolonged standing or kneeling
        • Carotid Sinus Syndrome 
    • Situational 
      • Trigger: cough, micturition, defecation. cardioinhibitory, vasodepressor or mixed, urinating, swallowing, neuralgia
  • DDX:
    • Must be dx of exclusion
    • Syncope or Seizure

Cardiac Related Syncope

  • Aortic stenosis, Hypertrophic Cardiomyopathy, Anomalous coronary arteries
    • Syncope with exertion or during exercise
  • Ventricular arrhythmias
    • prior history of CAD, MI, cardiomyopathy or decrease ejection fraction
  • Sick Sinus, bradyarrhythmia, AV block
    • sinus pauses, increase PR or increase QRS duration
  • Torsades de point (acquired QT prolongation)
    • hypokalemia, hypomagnesemia, medication causing increase QT interval
  • Congenital long QT syndrome
    • Family history of sudden death, increase QT interval, syncope with triggers (e.g., exercise, startle, sleeping)
 

Cardiopulmonary Syncope

  • Types:
    • Valvular stenosis 
    • CMPY
    • Pulmonary HTN
    • Congenital heart disease
    • Myxoma
    • Pericardial disease
    • Aortic dissection
    • Myocardial ischemia/infarction 
    • PE

Dysthymias Syncope

  • Bradydysrhythmias
    • – Short or long QT syndromes 
    • – Stokes-Adams attack
    • – Sinus node disease
    • – 2nd or 3rd-degree heart block
    • – Pacemaker malfunction 
  • Tachydysrhythmias
    • – VTach
    • – Torsade de Pointes
    • – SVT
    • – Afib/Aflutter