SYNCOPE

1
SYNCOPE

• General Medicine lecture
• John Liuzzo, M.D.

2
Outline

• Define syncope
• Distinguish syncope from other symptoms
• Differential diagnosis
• Diagnose the cause of syncope
• Diagnostic tests
• Determine need for hospitalization
• Drug therapy

3
Definition

• Syncope is a sudden and brief loss of
  consciousness associated with loss of postural
  tone, from which recovery is spontaneous.
• The pathophysiology of all forms of syncope
  consists of a sudden decrease in or brief
  cessation of cerebral blood flow.
• Associated symptoms lightheadness, visual
  blurring proceding to blindness, visual spots,
  diaphoresis, heaviness in LE, postural sway,
  nausea, vomiting, pallor or ashen gray face,
  sense of feeling bad

4
Prevalence

• Syncope is common and it is disabling
• Approximately 5-20 of adults will have one or
  more episodes of syncope by age 75
• Accounts for about 1 of hospital admissions and
  about 3 of emergency room visits
• Annual incidence in institutionalized elderly
  (gt75 y/o) is 6 previous lifetime episodes is
  23
• (JAMA 1992 2682553-60)

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Is it syncope?

• Distinguishing syncope from other symptoms
• Dizziness, presyncope, and vertigo do not result
  in loss of consciousness or postural tone
• Vertigo is associated with a sense of motion
• Drop attack which is falling without warning,
  often due to compression of the vertebral
  arteries or a hyperirritable carotid sinus,
  occurs without loss of consciousness
• The use of cardioversion to regain consciousness
  is by definition cardiac arrest, not syncope

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Distinguishing syncope from seizure

• Loss of consciousness precipitated by pain,
  exercise, micturition, defecation, or stressful
  events is usually syncope
• Sweating or nausea before or during the episode
  are associated with syncope an aura is typical
  of seizures
• Rhythmic movements, e.g. clonic or myoclonic
  jerks, suggests seizure, (but syncope can cause
  movements)
• Disorientation after the event, headaches, slow
  to return to consciousness, and unconsciousness
  lasting more than five minutes suggest a seizure

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Differential Diagnosis
(NEJM 2000 3431856-62)
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Neurally-mediated syncope(neurocardiogenic or
vasovagal syncope)

• Most common
• Result of reflex-mediated changes in vascular
  tone and heart rate
• Examples
• emotional fainting
• situational syncope (e.g. in response to
  micturition,
• cough, or
  defecation)
• carotid sinus syncope
• Glossopharyngeal neuralgia (and other painful
  states)
• panic
• exercise in athletes without heart disease

9
Neurally-mediated Syncope (cont.)

• Mechanism is poorly understood
• emotional upset may trigger CNS fainting
• activation of receptors in wall of bladder,
  esophagus, heart, respiratory tract, and carotid
  sinus lead to reflex vagal efferent activity and
  sympathetic withdrawal
• Net effect is a vicious cycle of inappropriate
  peripheral vasodilitation and relative
  bradycardia ? progressive hypotension and
  syncope (reversible by a supine posture or
  elevation of legs)
• Possible role of neurohormonal factors (e.g.
  serotonin, vasopressin, endorphins, epinephrine)

10
Cardiac Syncope

• Organic heart disease with reduced cardiac
  output
• Obstruction to LV outflow (e.g. aortic
  stenosis, hypertrophic obstructive
  cardiomyopathy, mitral stenosis, left atrial
  myxoma, ball-valve thrombus)
• Obstruction to pulmonary flow (e.g. pulmonic
  stenosis, primary pulmonary hypertension,
  pulmonary emboli)
• Myocardial massive MI with pump failure
• Pericardial cardiac tamponade
• Aortic dissection
• Reduced venous return Valsalva maneuver

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Cardiac Syncope (cont.)

• Arrhythmias
• Bradyarrhythmias
• Atrioventricular block (2nd or 3rd degree)
  with Stokes Adams attacks
• Sinus bradycardia, sinoatrial block,
  transient sinus arrest, sick sinus syndrome
• Pacemaker malfunction
• Tachyarrhythmias
• Episodic ventricular tachycardia with or
  without associated bradyarrhythmias
• Supraventricular tachycardia without AV block

12
Neurologic Diseases

• Primary autonomic disturbances with CNS signs
  (e.g. Shy Drager syndrome, Parkinsons Disease)
  or with peripheral nerve signs (e.g. GBS, and
  FDA)
• Secondary autonomic dysfunction (e.g. chronic
  ethanol, diabetes)
• Surgical sympathectomy
• Spinal cord disorders (e.g. syringobulbia)
• Posterior fossa tumors
• Cerebrovascular disturbance (e.g. TIAs,
  vertebral-basilar or carotid insufficiency, spasm
  of cerebral arterioles)

13
Orthostatic (Postural) Hypotension

• Defined as low blood pressure induced upon
  standing upright
• Criteria a decrease in systolic BP of gt20 mm
  Hg, or diastolic BP gt 10 mm Hg, after standing
  for at least 2 minutes
• Causes
• Volume depletion (e.g. acute illness,
  dehydration, GI bleeding, Addisons disease)
• Medications that alter vascular tone and HR
• Dysfunction of the vasoconstrictive
  reflexes in the blood vessels of the lower
  extremities

14
Medications Causing Syncope

• Vasodilators
• Nitrates
• ACE inhibitors
• Ca Channel blockers
• Hydralazine
• Alpha-adrenergic blockers
• Psychoactive Drugs
• Phenothiazines
• Tricyclic Antidepressants
• Barbiturates
• Narcotics
• Diuretics

• Drugs associated w/ Torsades de pointes
• Quinidine
• Procainamide
• Amioderone
• Sotolol
• Others
• Digitalis
• Insulin
• Marijuana
• Ethanol
• Cocaine

15
Psychiatric disorders

• Generalized anxiety disorder
• Panic disorder
• Major depression
• Alcohol and substance abuse
• Hysteria
• Conversion disorders
• predispose to neurally-mediated reaction

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Diagnosing the Cause of Syncope

• Careful history and physical exam (56-85)
• Electrocardiography is recommended, despite low
  yield because it can lead to decisions about
  immediate treatment (5)
• Routine use of basic laboratory tests
  (electrolytes, blood counts, renal function,
  glucose level) is not recommended because of low
  yield use only when specifically indicated by
  the H P (2)
• This initial assessment may lead to the diagnosis

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Initial Assessment Suggesting a Diagnosis

• Episodes occur after sudden unexpected pain,
  fear, or unpleasant sight, sound, or smell
• Episodes occur after prolonged standing at
  attention
• Episodes occur in well-trained athletes without
  heart disease after exertion
• Episodes occur during or immediately after
  micturition, cough, swallowing, or defecation

• Vasovagal syncope
• Vasovagal syncope
• Vasovagal syncope
• Situational syncope

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Initial Assessment Suggesting Diagnosis (cont.)

• Syncope is accompanied by throat or facial pain
  (glossopharyngeal or trigeminal neuralgia)
• Episodes occur with head rotation or pressure on
  carotid sinus (tumors, shaving, tight collars)
• Episodes occur immediately upon standing
• Patients take medications that may lead to a long
  QT interval or orthostasis and bradycardia

• Neurally mediated syncope with neuralgia
• Carotid sinus syncope
• Orthostatic hypotension
• Drug-induced syncope

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Initial Assessment Suggesting Diagnosis (cont.)

• Syncope is associated with headaches
• Patient is confused after episode, or loss of
  consciousnes lasts more than 5 minutes
• Syncope is associated with vertigo, dysarthria,
  or diplopia
• Episodes occur with arm exercise

• Migraines, seizures
• Seizure
• TIA, subclavian steal
• Subclavian steal

20
Initial Assessment Suggesting Diagnosis (cont.)

• Differences are found in BP or pulse between two
  arms
• Syncope and murmur occur with changes in position
  (from sitting to lying, bending, turning over in
  bed)
• Syncope occurs with exertion

• Subclavian steal or aortic dissection
• Atrial myxoma or thrombus
• Aortic stenosis, pulmonary hypertension, mitral
  stenosis, HOCM, CAD

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Initial Assessment Suggesting Diagnosis (cont.)

• Patient has a family history of sudden death
• Patient has a brief loss of consciousness with no
  prodrome, and has heart disease
• Patient has frequent syncope with no symptoms,
  but no heart disease

• Long-QT syndrome, the Brugada syndrome
• Arrhythmia
• Psychiatric Illness

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Importance of Heart Disease

• In evaluating syncope, the presence of structural
  heart disease is the most important factor for
  predicting the risk of death, and likelihood of
  arrhythmias.
• Patients with structural heart disease or an
  abnormal ECG have an increased risk of death in 1
  year
• Early studies showed that cardiac causes of
  syncope are associated with increased mortality
  and an increased risk of sudden death. It was
  later shown that underlying heart disease,
  despite the cause of the syncope, is the factor
  associated with increased risk of death.
• (Ann Emerg Med, 1997 29 459-66 Am J Med,
  1996 100 646-55)

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Patients with Structural Heart Disease or ECG
Abnormalities

• Concern is arrhythmia
• If cannot confirm structural heart disease (e.g.
  elderly) or syncope during exercise or known
  disease of undetermined severity echocardiography
  (5-10) and stress testing is recommended
• 24 hour ECG monitoring is recommended as well as
  consultation with a cardiologist
• Symptoms in conjunction with arrhythmias?
  arrhythmia is cause
• Symptoms without accompanying arrhythmia ?
  excludes arrhythmias
• In the remaining patients if arrhythmic syncope
  is still suggested by symptoms then
  electrophysiologic testing and/or continuous-loop
  event monitoring is recommended

24
Patients with Normal ECG Findings and No Heart
Disease

• Majority of patients without heart disease have
  neurally-mediated syncope (includes carotid sinus
  syncope and psych illnesses)
• Tilt table testing is recommended in patients
  with recurrent syncope or those with severe
  episodes (e.g. severe injury or MVA) or high-risk
  occupations (e.g. pilots)
• Perform carotid sinus massage in elderly patients
  to rule out carotid sinus syncope (but not in
  those with a carotid bruit or known
  cerebrovascular disease) (vasodepressor gt 3sec
  cardioinhibitory gt50 mmHg fall)
• If syncope and other somatic complaints consider
  psychiatric assessment

25
Testing for Arrhythmia

• Think arrhythmia in patients with structural
  heart disease or abnormal ECG if the symptoms
  suggest cardiac syncope
• (sudden brief loss of consciousness without a
  prodrome).
• The only way to include or exclude arrhythmia as
  the cause is to obtain a rhythm strip during
  syncope.

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Ambulatory (Holter) Monitoring

• Symptoms found in conjunction with arrhythmia in
  4 of patients ? diagnosis of arrhythmic syncope
• Symptoms occur without arrhythmia in 17 of
  patients ? rules out arrhythmic syncope
• The remaining 79 of patients either brief
  arrhythmias or no arrhythmias are found ? cannot
  exclude because may be episodic
• (Ann Intern Med 1990 113-53-68)
• Increasing the duration of monitoring to 72 hours
  does not increase the yield
• (Arch Int. Med 1990 150 1073-78)

27
ContinuousLoop Event Recorders

• Provides long-term monitoring-weeks to months
• Patient or an observer can activate the monitor
  after symptoms occur, thereby freezing in its
  memory the readings from the previous 2-5 minutes
  and the subsequent 60 seconds
• In patients with recurring syncope (gt 15
  episodes) arrhythmias were found during syncope
  in 8-20 normal rhythm found during symptoms in
  12-27
• (Am J Cardiol 1990 66 214-19 Br. Heart J.
  1987 58 251-253
• Limitations compliance, potential for errors in
  using device, and in transmission

28
Electrophysiologic Studies

• Yield of EP tests depends on whether there is
  structural heart disease or abnormal ECG

Induced V. Tach
Bradycardia
Structural heart disease
Abnormal ECG
Normal heart
(Ann Intern Med 1997 127 76-86)
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Tilt table Testing

• Most common response in patients with unexplained
  syncope is sudden hypotension, bradycardia, or
  both
• Tilt tesing is believed to provoke vasovagal
  syncope in susceptible persons symptoms,
  hemodynamic response, and release of
  catecholamines are similar
• ACC Guidelines on methods and indications in
  assessing syncope with tilt testing
  (JACC
  1996 28 263-75)
• Commonly use provocative agents such as
  isoproterenol or nitroglycerin
• The specificity of positive tilt test with
  chemical stimulation is near 90
• 
  (PACE 1997 20 Pt
  II781-7)

30
Neurologic Testing

• EEG provides diagnostic information in lt 2 of
  syncope cases
• Head CT scan provides new diagnostic information
  in only 4 of cases
• All of these patients had focal neurologic signs
  or symptoms suggestive of a seizure
• TIAs involving the carotid or vertebrobasilar
  arteries rarely result in syncope (drop
  attacksvertebrobasilar ischemia)
• No studies demonstrate the usefulness of cranial
  or carotid Doppler studies in evaluating syncope
• These studies are not recommended unless the
  patient has neurologic symptoms or signs of a TIA

31
Hospitalization

• For rapid diagnosis of the cause of syncope, or
  for treatment when the cause is known
• Recommendations for hospital admission are based
  on the potential for adverse outcomes if
  evaluation is delayed
• (no studies that focus on this issue)

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Hospitalize

• Examples
• CAD, CHF, valves, CHD, V. arrhythmias, P.E.
  findings
• Syncope w/ palpitation, chest pain, exertional
  syncope
• Ischemia, BBB, AV block, NSVT, Prolonged QT,
  accessory pathway, RBBB w/ ST elevation V1-V3,
  pacemaker malfunction
• New stroke or focal signs

• For diagnostic evaluation
• Structural heart disease
• Symptoms suggestive of arrhythmia or ischemia
• Electrocardiographic abnormalities
• Neurologic Disease

33
Hospitalize

• For treatment
• Structural heart disease
• Orthostatic hypotension
• Older age
• Adverse drug reactions

• Examples
• Acute MI, PE, aortic stenosis, HOCM
• Acute, severe, volume loss, dehydration, GI
  bleeding severe chronic
• Multiple coexisting abnormalities
• Torsades de pointes, long QT interval,
  anaphylaxis, orthostasis, bradyarrhythmias

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OUTPATIENT

• Patients with neurally mediated syncope, and
  those who do not have heart disease or an
  abnormal ECG can be evaluated as outpatients

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Treatment

• Patients encountered during an episode should be
  placed in a position that will maximize cerebral
  blood flow
• Prevent aspiration by turning head to side and
  give nothing by mouth until patient has regained
  consciousness
• Dont permit patient to arise until physical
  weakness has passed and patients should be
  observed for few minutes after rising
• Avoidance of circumstances that provoke event,
  (e.g. excitement, fatigue, arising rapidly from
  bed, medications)

36
Treatment (cont.)

• Treat the primary disorder in structural cardiac
  disease, arrhythmia, or neurologic conditions
• For orthostatic hypotension volume replacement
  and discontinuation of inciting drugs
• For autonomic failure increase salt and fluid
  intake, waist high support stockings, and drugs
  such as fludrocortisone and midodrine

37
Treatment (cont.)

• In neurocardiogenic syncope (positive tilt tests)
  prophylaxis with beta-blockers or disopyramide
  are used. A randomized controlled study showed
  benefit of atenolol after 1 month
• 
  (Am Heart J 1995 130 1250-3)
• Permanent pacemakers in those with recurrent
  symptoms and bradycardia on tilt table test
  resulted in 85 reduction in recurrent syncope
• 
  (JACC 1999 99 1452-7)
• Paroxetine was found in a randomized, blinded,
  placebo-controlled study to improve symptoms in
  patients with vasovagal syncope unresponsive to
  traditional medications
• 
  (JACC 1999 331227-30)

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Conclusion

• Syncope is a symptom not a disease, thus
  evaluation focuses on physiologic states that may
  cause the loss of consciousness-there is no gold
  standard test
• In evaluating syncope utilizing directed history
  taking and physical exams and directed diagnostic
  testing will lead to the diagnosis in the
  majority of patients
• Treatment focuses on improving patient quality of
  life and decreasing hospital admissions