2. DEFINITION
Syncope is the sudden, transient
loss of consciousness and postural
tone with subsequent spontaneous
recovery.
Greek Syn with koptein, meaning to
cut off
3. Before syncope, the patient may
experience a variety of prodromal
symptoms, typically including the
awareness of an impending faint.
The range of prognoses in syncope is
wide, and the main task of the
clinician, therefore, is to determine
whether the patient has a benign or a
life-threatening cause for syncope
5. Neurally Mediated Syncope
Vasovagal, vasodepressor, or
neurocardiogenic syncope also called
the common faint, is often caused by
a precipitating event such as
prolonged standing, hypovolemia
(commonly dehydration), fear, severe
pain, the sight
of blood, strong emotion, or
instrumentation; however, it can also
occur without obvious cause.
6.
7. Contd…
Situational or reflex syncope is loss of
consciousness during or immediately
after coughing, micturition, swallowing,
or defecation. Alcohol has been
implicated in micturition-related syncope.
Carotid sinus syncope is induced by
carotid sinus stimulation, resulting in
hypotension, bradycardia, or both. In
sensitive individuals, typically elderly
men, carotid sinus syncope may develop
with tight shirt collars or while shaving
the neck.
8. Orthostatic Syncope
This type of syncope results from orthostatic
hypotension, diagnosed by documentation of
a 20 mm Hg or more decrease in systolic
blood pressure during the initial 5 minutes
after the patient is in upright position; the
associated
heart rate either remains unchanged or
increases
Common cause of syncope in the elderly and
is exacerbated by medications
Autonomic insufficiency is a cause of
orthostatic hypotension in diabetic patients,
patients with Parkinson disease, and the
elderly.
9. Cardiac Syncope
Syncope associated with cardiovascular disease portends
a much higher risk of mortality than is the case in the
absence of underlying structural heart disease. At highest
risk of dying within 1 to 6 months
Arrhythmic
syncope results from tachyarrhythmias (ventricular or
supraventricular) and bradyarrhythmias
◦ Sinus arrest
◦ Atrial fibrillation(in WPW syndrome pt.)
◦ Sustained monomorphic VT
◦ Complete heart block
◦ LQTS
◦ Brugada syndrome
◦ Hypertrophic cardiomyopathy
◦ Pacemaker & ICD malfunction
10. Contd…
Structural syncope is caused by valvular
stenosis (aortic, mitral, pulmonic), prosthetic
valve dysfunction or thrombosis, hypertrophic
cardiomyopathy, pulmonary embolism,
pulmonary hypertension, cardiac tamponade,
anomalous origin of the coronary arteries
Aortic dissection,subclavian steal, severe left
ventricular dysfunction, and myocardial
infarction
Left atrial myxomas or ballvalve thrombi that
fall into the mitral valve during diastole can
result in the obstruction of ventricular filling
and in syncope.
11. Metabolic Disturbance
Syncope due to hypoglycemia is the loss of
consciousness that accompanies a blood
glucose level of less than 40 mg/dL and is
preceded by tremors, confusion, salivation,
hyperadrenergic state, and hunger.
Hypoglycemic syncope should be suspected
in diabetic patients who take insulin or oral
hypoglycemic agents.
the loss of consciousness caused by
hypoglycemia is not associated with
hypotension, persists even when the patient
is in the supine position, and usually does not
resolve until the blood glucose level is
restored to normal.
12. Hypoadrenalism, which can cause
postural hypotension as a result of
inadequate cortisol secretion
suspected when long-term steroid
therapy is suddenly discontinued
13. Neurologic Disease
Neurologic conditions can mimic
syncope by causing impairment or loss
of consciousness; conditions include
transient cerebral ischemia , migraines ,
temporal lobe epilepsy, atonic seizures,
and unwitnessed grand mal seizures.
Disorders resembling syncope, but
without loss of consciousness, include
drop attacks (sudden loss of postural
tone), cataplexy, and transient ischemic
attacks of carotid origin
14. Psychiatric Conditions
Syncope or syncope-like syndromes associated
with psychiatric conditions not associated with
increased rates of mortality but have high 1-year
recurrence rates (up to 50%)
Psychiatric conditions associated with syncope
include generalized anxiety and panic
disorders(hyperventilation leads to cerebral
vasoconstriction and possible loss of
consciousness), major depression,alcohol and
substance abuse, and somatization disorders.
it is possible that recurrent syncope itself may
secondarily give rise to psychiatric conditions such
anxiety and panic attacks. A diagnosis of syncope
resulting from psychiatric disorders is usually made
15. Unexplained Aetiology
Earlier studies reported that, in about
half of the patients with syncope, no
cause could be determined.
17. KEYS TO THE HISTORY
Rule out
◦ Structural heart disease(aortic
stenosis, hypertrophic
cardiomyopathy etc.)
◦ Life-threatening conditions(Acute MI,
Upper GIT hemorrhage)
18. Emphasis should be placed on,
◦ Circumstances surrounding syncopal
event
◦ Nature of prodromal & associated
symptoms
◦ Characterization of the recovery period
◦ Medications and drugs
◦ Presence of known cardiac disease
◦ Family history (e.g., Cardiomyopathy or
LQTS)
◦ Psychiatric Hx
◦ Relation of syncopal events to posture,
exertion & palpitations.
◦ Number & chronicity of prior syncopal and
near-syncopal episodes
19. Circumstances Surrounding
Onset
Sudden onset without a prodrome
Arrhythmias
Autonomic symptoms (pallor,
diaphoresis, nausea)+ precipitating
factor(pain, extreme heat/emotion,
viewing an unpleasant sight/prolonged
standing) Vasovagal syncope
If immediately on standing
Orthostatic syncope
Immediately after swallowing, coughing,
defecation&micturition(Alcohol)
Situational syncope
20. Contd…
With head rotation while the person is
wearing tight collars Carotid syncope
Exertional syncope Structural heart
disease(AS, Hypertrophic
cardiomyopathy/Exercise-induced
tachycardias)
Syn. in arm exercise Subclavian steal
syndrome
Syn. in physical exertion (swimming),
emotional stress,sudden, unexpected
acoustic stimuli (sound of an alarm clock or
telephone) LQTS
21. Posture at the Onset of
Attack
Vasodepressor syncope in the upright
position
Independent of posture Syn. resulting from
arrhythmias and other
causes(hypoglycemia /hyperventilation) that
resemble Syn.
Pain/emotion-related vasovagal syncope-
No any posture (needlestick/on the sight of
blood/injury)
By definition, syncope caused by orthostatic
hypotension occurs soon (within seconds to
minutes) after the patient assumes an
22. Associated Symptoms
Not always present &depend on the cause
of syncope.
Neurally Mediated Syncope
◦ Feel unsteady
◦ Be confused
◦ Ringing in the ears
◦ Visual disturbances(dimming/blurring/seeing
spots)
◦ Warmth
◦ Nausea/Vomiting
◦ Facial pallor &diaphoresis
23. Contd…
Palpitations preceding cardiac syncope, especially
an awareness of rapid heart beating, suggest an
arrhythmic origin.
Neurologic syncope: brainstem findings (vertigo,
dysarthria, ataxia, visual disturbances)
Postevent confusion is more likely to be caused by
seizures
Loss of consciousness associated with headache
indicates migraine or seizures
Throat / facial pain suggests glossopharyngeal or
trigeminal neuralgia
24. Differentiating Syncope from
Seizures
Clinically challenging
Both phenomena loss of consciousness
Myoclonic jerking may occur during the course of
true syncope secondary to transient cerebral
hypoxia
Patient>45years, disorientated after an episode,
seizures are 5 times more likely.
◦ An exception!!!
◦ Arrhythmic syncope with a prolonged
hypotensive episode
◦ Secondarily cause transient cerebral hypoxic
injury and postevent disorientation
25. CLINICAL FEATURES SYNCOPE SEIZURES
Loss of consciousness precipitated by micturition,
exercise, pain,defecation, or stressful events
+ -
Sweating and nausea before or during the event + -
Aura - +
Tongue biting - +
Clonic or myoclonic jerks or rhythmic movements +/- ++
Disorientation after the event - +
Slowness in returning to consciousness - +
Unconscious >5 min - +
28. Drugs
Drugs can frequently cause syncope, particularly in
the elderly.
Antihypertensive agents:doxazosin, clonidine,
hydralazine,prazosin, angiotensin-converting
enzyme inhibitors, and angiotensin II-receptor
blockers.
Other drugs:morphine, nitroglycerin,
phenothiazines, perioperative amiodarone, calcium
channel blockers(nifedipine), citrated blood,
aggressive diuretic therapy, interleukin-2,
protamine, and quinidine.
After exposure to QT-prolonging drugs previously
asymptomatic gene carriers may suddenly develop
syncope/cardiac arrest caused by torsades de
29. Contd…
QT-prolonging drugs known to precipitate
syncope by torsades de pointes include:
◦ Cardiac drugs:quinidine, procainamide,
sotalol, disopyramide, amiodarone, and
dofetilide
◦ Noncardiac drugs:macrolides, tricyclic
antidepressants, phenothiazines,
methadone, some antihistamines, and
cisapride.
◦ Prone to induce torsades de pointes
Women>Men
30. Pregnancy
Common in pregnancy
3rd trimester even in the supine
position
◦ Compression of the Aorta and IVC
by the enlarged uterus
31. HELPFUL SIGNS ON
PHYSICAL EXAMINATION
Recording of HR
◦ Severe bradycardia:2nd / 3rd degree heart block
◦ Tachycardia: Ix of ventricular or supraventricular
tachyarrhythmia.
Recording of supine&erect BP
◦ Orthostatic hypotension:20-mm Hg decrease in
SBP or a 10-mm Hg decrease in DBP within 5
min after the patient stands upright
Aortic dissection:Assessment of pulse deficit & BP
in the arms
Auscultation for ejection systolic murmur:AS &
hypertrophic cardiomyopathy
39. Threshold for admitting a patient, relatively low.
Emergency room to exclude life-threatening
cardiopulmonary conditions (acute MI, pulmonary
embolism), hypoglycemia, orthostatic hypotension &
life-threatening arrhythmias (drug-induced torsades
de pointes.)
Recurrent syncope,require hospitalization if,
◦ Not previously, evaluated/treated
◦ Suspected cardiopulmonary disease
◦ FHx of sudden death
◦ Possible secondary injury present
◦ Failure of treatment (especially of cardiac origin)
◦ Suspected pacemaker /ICD malfunction
Pt. with recurrent syncope, remains unexplained after
initial medical evaluation/ known/ suspected cardiac
origin, referred to a Cardiologist /Electrophysiologist
40. TAKE HOME MESSAGE…
Major challenge in the evaluation,
◦ Transient symptom, not a disease
◦ With causes ranging from benign to life-
threatening
◦ No gold-standard test for establishing the
diagnosis
But !!!
◦ With the appropriate use of HISTORY,
PHYSICAL SIGNS, and DIAGNOSTIC
TESTS patients with life-threatening
syncope can be identified with a high
degree of accuracy.
