Syncope

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Syncope

• Teresa Menendez Hood , M.D.

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Definition

• Syncope is a symptom in which there is transient
  (lt30 secs) and self-limited loss of consciousness
  usually leading to a fall. The onset is rapid and
  recovery is spontaneous, complete and prompt. The
  underlying mechanism is relatively abrupt
  cerebral hypoperfusion.The onset may or may not
  have warning and some older patients may have
  retrograde amnesia. Fatigue is common
  post-syncope.

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SYNCOPE STATS

• 25 people will have syncope at some point
• 6 of hospital admits are for syncope
• 3 of all ER visits
• 30 have recurrences
• 40 remain undiagnosed after initial evaluation

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Syncope Etiology
Orthostatic
Cardiac Arrhythmia
Structural Cardio- Pulmonary
Non- Cardio- vascular
Neurally- Mediated


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Unknown Cause 34
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Causes of Syncope

• Neurally-mediated reflex syncope-a reflex that
  when triggered gives rise to vasodilation and/or
  bradycardia
• Vasovagal -look for precipitating events fear,
  pain, prolonged standing
• Carotid sinus -turning head to one side, age gt40
• Situational -cough, micturition, post-exercise,
  post-prandial, swallow, defecation.

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Causes of Syncope

• Orthostatic
• Autonomic Failure- the autonomic nervous system
  does not work well and one does not get the
  vasoconstrictor mechanisms to upright posture
• primary or multisystem, secondary (DM, amyloid),
  drug induced (the most common). Look for
  autonomic problems in other organs..i.e cannot
  sweat, impotence, disturbed micturition
• Volume depletion
• Cardiac Arrhythmias
• Sinus node dysfunction, AVN disease, SVT/VT,
  inherited diseases(LQT, Brugada, WPW,ARVD,HCM)

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Causes of Syncope

• Structural Cardiac or Cardiopulmonary disease-
  an obstruction of blood flow
• Valvular disease
• Obstructive CM
• Atrial Myxoma
• Aortic dissection
• Tamponade
• PE

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Causes of Syncope

• Cerebrovascular
• Vascular steal syndrome -subclavian stealrare,
  syncope associated with arm exercise the blood
  vessel supplies both the brain and the arm. Check
  for BP in both arms!
• Vetebrobasilar TIA -doubtful that can really
  cause syncope

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Features suggestive of cardiac causes?

• Occur in the supine position or during exertion
• Preceded by palpitations
• Presence of severe heart disease
• EKG abnormalities wide QRS, AV conduction
  disease, Q waves, LQT, delta wave, SQT, epsilon
  wave

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Features suggestive of Neurally-Mediated causes?

• Prolonged standing in crowded, warm place
• Preceding nausea, feeling cold and sweaty
• After exertion or post-prandial
• Tonic-clonic movements are short in duration and
  occur after the loss of consciousness
• Long duration of symptoms gt4years

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Causes of non-syncopal attacks

• Impairment of /loss of consciousness
• Metabolic-hypoglycemia , hypoxia,
  hyperventilation syndrome
• Epilepsy-Typical premonitory aura? Post-ictal
  state?
• Loss of muscle control
• Cataplexy-usually with narcolepsy
• Psychogenic

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The Initial Evaluation

• Careful History - from patient and witnesses
  this is the most important tool in the diagnosis!
• Prior to attack, onset, eyewitnesses, end of the
  attack, PMH, FH, drug history?
• Physical exam- include orthostatic BP
• Standard EKG

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Evaluation

• The use of EEG, CT, MRI , carotid dopplers are
  not usually helpful in the workup of syncope
• Hospitalize patients when the features suggest a
  cardiac cause, when it results in severe injury,
  or when the syncope is frequent

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Evaluation

• When the cause of the syncope is not evident
  after the initial evaluation and there is
  evidence of heart disease then the possibility of
  cardiac syncope must be entertained as these
  patients have a high mortality at one year(18-30
  mortality)
• Cardiac evaluation echo, stress test,
  holter/loop and EP testing.
• In a patient with cardiac disease but with
  negative cardiac workup, then proceed with tilt
  testing and / or implantable loop recorder.

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Evaluation

• In those without heart disease, then tilt table
  testing and carotid massage (more important in
  the patients gt 40) for neurally mediated syncope
  is recommended for those with recurrent or severe
  syncope.
• SAECG has fallen out of favor. If it is normal it
  helps.

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Test/Procedure Yield (based on mean time to diagnosis of 5.1 months7
History and Physical (including carotid sinus massage) 49-85 1, 2
ECG 2-11 2
Electrophysiology Study without SHD 11 3
Electrophysiology Study with SHD 49 3
Tilt Table Test (without SHD) 11-87 4, 5
Ambulatory ECG Monitors
Holter 2 7
External Loop Recorder (2-3 weeks duration) 20 7
Implantable Loop Recorder (up to 14 months duration) 65-88 6, 7
Neurological (Head CT Scan, Carotid Doppler) 0-4 4,5,8,9,10
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Reveal Plus ILR

• Offers up to 14 months of continuous, leadless
  ECG monitoring
• High diagnostic yield (65-88)
• High patient compliance
• Patient and auto triggered to capture ECG

Patient Activator
Reveal Plus ILR
9790 Programmer
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• Implant zone for optimal auto activation
  performance

• Implant parallel to the midline in the region
• From left parasternal area to the mid-clavicular
  line
• First to the fourth rib

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Randomized Assessment of Syncope Trial
(RAST) Comparison of the Implantable Loop
Recorder with Conventional Diagnostic Testing for
Unexplained Syncope1
Andrew D. Krahn, George J. Klein, Raymond Yee,
Allan C. Skanes University of Western
Ontario London Ontario Canada
1. Krahn A, et al. Circ. 2001104(11)46-51
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Methods

• Prospective randomized trial (60 patients with
  unexplained syncope referred for cardiac
  investigation)
• Inclusion
• Recurrent unexplained syncope
• Referred to the arrhythmia service for cardiac
  investigation
• No clinical diagnosis after history, physical,
  ECG and at least 24 hours of cardiac monitoring
• Exclusion
• LVEF lt 35
• Unable to give informed consent
• Major morbidity precluding 1 year of follow-up

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1. External loop recorder(ELR)
2. Head up tilt test(HUT)
3. Electrophysiological study(EPS)
4. Insertable Loop Recorder(ILR)

Methods

• Conventional Investigations
• ELR then HUT then EPS(see below for definitions)
• ILR4
• Left sided implant with antibiotics
• Patient education
• 1 year of follow-up
• Crossover
• After primary arm was completed, patients were
  offered crossover to facilitate diagnosis

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Results
ILR (n30) Conventional (n30) Age
(years) 64 /- 14 68 /- 14 Gender (
male) 19 (63) 14 (47) Syncopal Episodes 4.1
/- 3.3 5.8 /- 6.6 Duration of Syncope
(yrs) 6.6 /- 12 8.7 /- 2.7 LVEF () 55 /-
8 55 /- 6
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RAST Results Randomized Assessment of Syncope
Trial
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RAST Crossover Results
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RAST Results
Diagnosis By ILR Conventional p
value Primary Strategy 14/27 (52) 6/30
(20) p0.012 Crossover 8/13 (62) 1/6
(17) p0.069 Primary and Crossover 22/40
(55) 7/36 (19) p0.0014 3 primary ILRs and 8
crossover ILRs have not completed follow up.
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Conclusions

• This prospective randomized trial suggests that
  the implanted loop recorder has a superior
  diagnostic yield as a primary strategy.
• The diagnostic yield of conventional testing in
  these patients is disappointing (19).
• The loop recorder retains high utility when used
  after conventional testing is negative.
• Consideration should be given to use at an
  earlier stage in the diagnostic cascade in this
  patient population.

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Asystole Brady NormalSR Tachy Syncope Recurrence
Pilot studyCirculation, 95 N/A 7 (47) 6 (40) 2 (13) 15/1694
Krahn et alCirculation, 99 N/A 14 (69) 7 (30) 2 (9) 23/8527
Nierop et alPACE, 2000 N/A 4 (29) 6 (43) 4 (29) 14/3540
ISSUE studyCirculation, 2001 16 (50) 3 (9) 12 (34) 1 (3) 32/11129
Total 4452 4452 3137 911 84/24734
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Indications
The Reveal Plus Insertable Loop Recorder is
indicated for

• Patients with clinical syndromes or situations at
  increased risk of cardiac arrhythmias
• Patients who experience transient symptoms that
  may suggest a cardiac arrhythmia

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Tilt Table Diagnosis

• Neurocardiogenic-seen in 50 of patients with
  heart disease and 75 of patients without heart
  disease who present with syncope
• Type 1 mixed bp falls before heart rate and the
  heart rate does not get lt40 and no pauses gt3 secs
  and heart rate falls at the time of syncope
• Type 2a cardioinhibitory without asystole-bp
  falls before the heart rate and heart rate gets
  below 40 but no asystole gt 3 secs
• Type 2b cardioinhibitory with asystole-heart
  rate falls below 40 for gt 10secs and asystole is
  present gt3 secs
• Type 3 pure vasodepressor-bp falls but heart
  rate does not fall gt10 from peak heart rate .

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Tilt Table Diagnosis

• Dysautonomic
• Gradual decline in the systolic and diastolic bp
  with or without a drop in the heart rate.
• Orthostatic intolerance is the key problem
• POTS-Postural orthostatic tachycardia syndrome
• An excessive heart rate response to maintain a
  low normal blood pressure. Will have an excess of
  gt30 beats increase when placed upright

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Tilt Table Diagnosis

• Cerebral syncope
• Associated with cerebral vasoconstriction in the
  absence of systemic hypotension and would need a
  transcranial Doppler for confirmation
• Psychogenic

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Protocols

• Westminster
• Passive tilt for 45 minutes at 60-80 degrees and
  has a positive rate of 75 with specificity of
  95

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Protocols

• Italian
• Passive tilt for 20 minutes and the challenge
  with SUBLINGUAL NITROGLYCERIN while still upright
  and has specificity of 94.
• Will see a progressive drop in the BP with no
  bradycardia if the effect is due to the drug
  alone and this is not a positive test..seen in
  20!

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Syncope
History and Physical ECG
KnownSHD
NoSHD
gt 30 days gt 2 Events
lt 30 days
Echo
EPS
-

Treat
Tilt/ILR
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