Nothing to disclose Syncope Is t he abrupt and transient loss of consciousness associated with absence of postural tone followed by complete and usually rapid spontaneous recovery Syncope alarming for the individual witnesses family and providers ID: 774769
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Slide1
Syncope
Victoria E Judd
Slide2Disclosure Slide
Nothing to disclose
Slide3Slide4Slide5Syncope Is
t
he abrupt and transient loss of consciousness
associated with absence of postural tone
followed by complete and usually rapid spontaneous recovery
Slide6Syncope
alarming for the individual, witnesses, family, and providers
most often benign and self-limited
a harbinger of a multitude of disease processes
i
njuries resulting from
syncopal
attacks occur in about one-third of patients
recurrent episodes can be psychologically devastating
can be a premonitory sign of cardiac arrest, especially in patients with organic heart disease
Slide7Syncope
The most frequent age for first syncope is 15 years.The lifetime incidence of 1 fainting episodes is ∼40%.
Vasovagal Syncope
Mediated by emotional distress: fear, pain, instrumentation, blood phobia
Mediated by orthostatic stress
Slide9Situational Syncope
Cough, sneeze
Gastrointestinal stimulation (swallow, defecation, visceral pain)
Micturition (
postmicturation
)
Post-exercise
Postprandial
Others (e.g., laughter, brass instrument playing, weightlifting)
Carotid sinus syncope
Slide10Syncope Due to Orthostatic Hypotension
Primary autonomic failure:
Pure autonomic failure, multiple system atrophy, Parkinson's disease with autonomic failure,
Lewy
body dementia
Secondary autonomic failure:
Diabetes, amyloidosis, uremia, spinal cord injuries
Drug-induced orthostatic hypotension:
Alcohol, vasodilators, diuretics, phenothiazine's, antidepressants
Volume depletion:
Hemorrhage, diarrhea, vomiting, etc.
Slide11Cardiac Syncope
Arrhythmia as primary cause:
Bradycardia:
Sinus node dysfunction (including bradycardia/tachycardia syndrome)
Atrioventricular
conduction system disease
Implanted device malfunction
Tachycardia:
Supraventricular
Ventricular (idiopathic, secondary to structural heart disease or to
channelopathies
)
Drug-induced bradycardia and
tachyarrhythmias
Cardiac Syncope
Structural disease:
Cardiac: cardiac
valvular
disease, acute myocardial infarction/ischemia, hypertrophic cardiomyopathy, cardiac masses (atrial
myxoma
, tumors, etc.), pericardial disease/
tamponade
, congenital anomalies of coronary arteries, prosthetic valves dysfunction
Others: pulmonary embolus, acute aortic dissection, pulmonary hypertension
Slide13Causes of Syncope
■Reflex (
neurally
-mediated; this includes vasovagal, POTS) — 58 percent
■Cardiac disease, most often a
bradyarrhythmia
or tachyarrhythmia — 23 percent
■Neurologic or psychiatric disease — 1 percent
■Unexplained syncope — 18 percent; a higher value (41 percent) was noted in another large series
Slide14Slide15Slide16Slide17Slide18Slide19Slide20Slide21The initial evaluation should answer three key questions
■Is it a
syncopal
episode or other type of event?
■Has the etiology been determined?
■Is there evidence suggestive of a high risk of cardiovascular events or death?
Slide22Slide23Slide24If Yes, Then Syncope
■Was loss of consciousness complete?
■Was loss of consciousness transient with rapid onset and short duration?
■Did the patient recover spontaneously, completely and without
sequela
?
■Did the patient lose postural tone?
Slide25Recurrent Syncope
The number of
syncopal
episodes can predict the risk of recurrence.
Slide26Slide27Clinical features that suggest a diagnosis on initial evaluation
Neurally
mediated syncope:
Absence of heart disease
Long history of recurrent syncope
After sudden unexpected unpleasant sight, sound, smell or pain
Prolonged standing or crowded, hot places
Nausea, vomiting associated with syncope
During a meal or post-prandial
With head rotation or pressure on carotid sinus (as in tumors, shaving, tight collars)
After exertion
Slide28Clinical features that suggest a diagnosis on initial evaluation
Syncope due to Orthostatic Hypotension(OH):
After standing up
Temporal relationship with start or changes of dosage of
vasodepressive
drugs leading to hypotension
Prolonged standing especially in crowded, hot places
Presence of autonomic neuropathy or Parkinsonism
Standing after exertion
Slide29Clinical features that suggest a diagnosis on initial evaluation
Cardiovascular syncope:
Presence of definite structural heart disease
Family history of unexplained sudden death or
channelopathy
During exertion, or supine
Abnormal ECG
Sudden onset palpitation immediately followed by syncope
Slide30Cardiovascular syncope:
ECG findings suggesting arrhythmic syncope:
-
Bifascicular
block (defined as either LBBB or RBBB combined with left anterior or left posterior fascicular block)
- Other
intraventriclar
conduction abnormalities (QRS duration ≥0.12 s)
-
Mobitz
I second degree AV block
- Asymptomatic inappropriate sinus bradycardia (<50 bpm), sinoatrial block or sinus pause ≥3 s in the absence of negatively
chronotropic
medications
Slide31Cardiovascular syncope:
- Non-sustained VT
- Pre-excited QRS complexes
- Long or short QT intervals
- Early repolarization
- RBBB pattern with ST-elevation in leads V1-V3 (
Brugada
syndrome)
- Negative T waves in right precordial leads, epsilon waves and ventricular late potentials suggestive of ARVC
- Q waves suggesting myocardial infarction
Slide32Slide33Slide34Figure 2. Different patterns of QT prolongation in LQTS. Morphology of the QT segment and T wave may be different in different genetic subsets of the LQTS, although there is significant individual variation.
Strickberger S et al. Circulation 2006;113:316-327
Copyright © American Heart Association, Inc. All rights reserved.
Slide35Figure 3. ECG changes in the Brugada syndrome.
Strickberger S et al. Circulation 2006;113:316-327
Copyright © American Heart Association, Inc. All rights reserved.
Slide36Slide37Slide38History
"Auras" are associated with seizures. In comparison, vasovagal (
neurocardiogenic
/reflex) syncope is usually, but not always, associated with a
prodrome
of nausea, warmth, pallor, lightheadedness, and/or diaphoresis.
Sudden onset of syncope without a
prodrome
is more common among patients with cardiac syncope (arrhythmic or mechanical cardiac etiology).
Slide39History
Neurocardiogenic
syncope commonly occurs when the patient is erect, not usually when supine.
Syncope resulting from orthostatic hypotension is frequently associated with the change from a supine to erect posture.
In comparison, syncope that occurs when the patient is supine suggests an arrhythmia.
Slide40History
An evaluation to rule out potentially life-threatening causes for syncope is required if syncope occurs during exertion
Slide41History
A prolonged loss of consciousness may indicate a seizure. By comparison, arrhythmias and
neurocardiogenic
syncope are often associated with a brief period of syncope, since the supine position reestablishes some blood flow to the brain and can therefore result in the restoration of consciousness. Recovery of consciousness may occur even if the arrhythmia is maintained.
Slide42History
Persistence of nausea, pallor, and diaphoresis in addition to a prolonged recovery from the episode suggest a vagal event. These findings are helpful in distinguishing
neurocardiogenic
syncope from syncope due to an arrhythmia. Significant neurologic changes or confusion during the recovery period may be due to a stroke or seizure.
Slide43History
A witness to the
syncopal
event may verify the loss of consciousness, any associated limb movements, and the presence or absence of pallor, diaphoresis, or a pulse.
Neurocardiogenic
syncope is more likely to occur among young, otherwise healthy patients.
Slide44History
Important elements of the family history include history of sudden death, pacemakers in young people, syncope, seizures, single car accidents, drowning, cardiomyopathy.
Slide45History
Seizures are the probable cause of 5 to 15 percent of apparent
syncopal
episodes. They can mimic syncope when the seizure is atypical and not associated with tonic-
clonic
movements, the seizure is not observed, or a complete history cannot be obtained. In addition, some patients with syncope present with myoclonic or other involuntary movements that are suggestive of a seizure but are actually due to cerebral hypoxia.
Slide46History
One distinguishing feature is that patients with seizures rarely have a rapid and complete recovery. Instead, the postictal state is characterized by a slow and complete recovery.
Another feature is usually those with syncope are pale and those with seizures are usually flushed.
Slide47Physical Exam
Blood pressure obtained in the supine, sitting, and erect position may detect orthostatic hypotension.
Slide48Orthostatic Measurement
Orthostatic blood pressure measurement is performed with the patient standing after at least three minutes of lying supine. Blood pressure should be measured each minute (or more often) in the standing position for three minutes or more (or as long as the patient tolerates) until the blood pressure nadir is reached. A sphygmomanometer (manual blood pressure cuff) may allow greater flexibility than an automatic arm-cuff device in measuring blood pressure prior to and during active standing
Slide49Orthostatic syndromes
■Classic orthostatic hypotension (OH) is defined as a decrease in systolic blood pressure (BP) of ≥20 mmHg and in diastolic BP ≥10 mmHg within three minutes of standing. This syndrome is diagnosed by active standing or tilt testing.
■Initial OH is defined by a BP decrease immediately on standing of >40 mmHg with BP spontaneously and rapidly returning to normal, so the period of hypotension and symptoms is <30 s. This is diagnosed by active standing.
Slide50Orthostatic syndromes
■Reflex syncope (vasovagal syncope) triggered by standing is characterized by an initial normal adaption reflex followed by rapid fall in venous return and vasovagal reaction (reflex bradycardia and vasodilatation). This is diagnosed by tilt table.
■Delayed (progressive) OH is defined by a slow progressive decrease in systolic BP on standing with no
bradycardic
reflex (in contrast to reflex syncope). This is diagnosed by tilt table.
Slide51Orthostatic syndromes
■Delayed (progressive) OH plus reflex syncope occurs when a vasovagal reaction (reflex bradycardia and vasodilation) follows delayed OH. This is diagnosed by tilt table.
Slide52Orthostatic syndromes
■Postural orthostatic tachycardia syndrome (POTS) presents with severe orthostatic intolerance (not syncope) with marked increase in heart rate (by >30 beats per minute or to >120 beats per minute)within ten minutes of standing. This is diagnosed by tilt table or passive standing. POTS can be diagnosed with bedside measurements of heart rate and blood pressure taken in the supine (laying down) and standing up position at 2, 5 and 10 minute intervals.
In
children and adolescents, a revised standard of a 40 bpm or more increase has recently been
adopted.
Slide53Slide54Physical Exam
The heart rate may be rapid or slow due to a number of possible rhythm disturbances, or irregular due to atrial fibrillation.
The pulse and blood pressure should be obtained with the patient supine, seated, and erect.
Hyperventilation can be seen with pulmonary embolism or psychiatric causes of syncope.
Slide55Physical Exam
The cardiac examination may reveal the murmur of aortic stenosis, pulmonic stenosis, or atrial
myxoma
(mitral stenosis).
Pulmonary hypertension may be suggested by a loud, palpable P2.
Increase in an outflow murmur with the Valsalva maneuver may help diagnose hypertrophic cardiomyopathy.
Slide56Physical Exam
Unilateral abnormalities found upon neurologic examination may reflect a cerebral vascular accident.
Slide57ECG
An electrocardiogram (ECG) should be obtained in all patients with syncope. The ECG is suggestive of an arrhythmic cause of syncope if any of the following abnormalities is present:
■
Bifascicular
block (defined as left bundle branch block or right bundle branch block combined with left anterior or left posterior fascicular block)
■Other
intraventricular
conduction abnormalities (QRS duration ≥0.12 sec)
■
Mobitz
II second degree
atrioventricular
block
Slide58ECG
■Asymptomatic sinus bradycardia (<50 beats/min), sinoatrial block or sinus pause ≥3 seconds in the absence of negatively
chronotropic
medications
■
Preexcited
QRS complexes, suggesting Wolff-Parkinson-White syndrome
■Long or short QT intervals
■Right bundle branch block pattern with ST-elevation in leads V1-V3 (
Brugada
syndrome)
■Negative T waves in right precordial leads, epsilon waves and ventricular late potentials suggestive of
arrhythmogenic
right ventricular cardiomyopathy
■Q waves suggesting myocardial infarction
Slide59Testing
Additional testing is based on the results of the initial evaluation. A variety of tests, mostly cardiologic, can be used in the evaluation of the patient with syncope. Neurologic testing is generally of low yield and overused, unless specifically suggested by history or physical examination.
■Carotid sinus massage in patients >40 years old.
■Echocardiogram when there is previous known heart disease or data suggestive of structural heart disease or syncope secondary to cardiovascular cause.
Slide60Testing
Immediate ECG monitoring when there is a suspicion of arrhythmic syncope.
■Orthostatic challenge (lying to standing orthostatic test or head-up tilt testing) when syncope is related to the standing position or there is suspicion of a reflex mechanism
■Other less specific tests such as neurological evaluation or blood tests are indicated only when there is suspicion of non-
syncopal
transient loss of consciousness.
Slide61Slide62Slide63Slide64Testing
E
chocardiography is recommended in patients with syncope when structural cardiac disease is suspected.
Electrocardiographic (ECG) monitoring is indicated if there is a high probability of identifying an arrhythmia associated with syncope.
Electrophysiology study (EPS) is indicated in selected patients with unexplained syncope.
Slide65Implantable Loop Recorders (ILR)
ILR
Patient
Assist Device
Automatically detects
bradycardia
tachycardia
asystole
Records rhythm at
time of trigger
Slide66ILRs
Slide67Example tracing from ILR
Slide68ILR in unexplained syncope with normal conventional work-up
Tachycardia
56%
11%
33%
Asystole /
bradycardia
No arrhythmia
Diagnostic yield: 35%
(175/506 patients)
Brignole et al. Europace 2009;11,671-687
Slide69Testing
Neurologic tests, including electroencephalogram (EEG), brain CT scan, brain magnetic resonance imaging, and carotid Doppler ultrasound, are frequently obtained in patients with syncope. In one review of 649 patients, 53 percent had at least one neurologic test. However, such testing was rarely useful.
Slide70Slide71Postural Orthostatic Tachycardia Syndrome (POTS)
A form of orthostatic intolerance occurs in patients, particularly younger adults and children, who consistently or frequently experience symptoms of orthostatic intolerance in response to postural stressors.
Autonomic reflexes are relatively preserved in these patients, and orthostatic hypotension and syncope rarely occur.
Some patients may have slightly elevated blood pressure.
The hallmark of this disorder is an exaggerated heart rate increase in response to postural change.
Slide72Names of POTS
■Chronic orthostatic intolerance
■Mild orthostatic intolerance
■Orthostatic tachycardia
■
Sympathotonic
orthostatic hypotension
■
Hyperdynamic
beta adrenergic state
■Idiopathic hypovolemia
■Mitral valve prolapse syndrome
■
Neurocirculatory
asthenia
■Irritable heart
■Soldier's heart
■Effort syndrome
Slide73Facts POTS
It is the most prevalent form of orthostatic intolerance. It is estimated that 500,000 Americans suffer from this disorder.
It is the most common syndrome of young people seen in autonomic dysfunction clinics.
Patients present at a relatively young age (14 to 45 years).
Slide74Facts POTS
Women predominate among patients with POTS with a female to male ratio of 4-5:1.
The reason for this is not known, however, observed gender differences in muscle sympathetic nerve discharge characteristics in healthy patients may explain why women are more likely to develop POTS.
Slide75Etiology POTS
The etiology of postural tachycardia syndrome (POTS) is heterogeneous. Investigators have reported a number of different abnormalities in patients with POTS.
It remains uncertain as to which of these abnormalities are primary and causative and which are secondary.
Slide76Etiology POTS
Distal denervation — Several clinical and empiric observations suggest the presence of distal, predominantly lower extremity, denervation with preserved cardiac innervation in this disorder.
Slide77Etiology POTS
Hypovolemia — Patients with POTS frequently experience symptomatic improvement with saline infusion.
Additional evidence of a decrease and/or redistribution of blood volume is observed in several studies of patients with POTS, which have noted:
■Hypovolemia
■Trend toward hypovolemia
■Reduced erythrocyte volume
■Excessive venous pooling with redistributive
hypovolemia
Slide78Etiology POTS
Changes in venous function — Abnormal venous function with decreased venous return on assumption of the upright posture could stimulate a compensatory tachycardia in order to maintain cardiac output.
Baroreflex
abnormalities — The increase in heart rate without blood pressure change upon standing in POTS suggests a primary abnormality in
baroreflex
control.
Slide79Etiology POTS
Increased sympathetic activity — Increased sympathetic activity is the final common pathway of most proposed mechanisms in POTS.
Genetic abnormalities — In one large series, 12.5 percent of 152 patients with POTS reported a family history of orthostatic intolerance
Slide80Clinical POTS
Patients with postural tachycardia syndrome (POTS) report dizziness, lightheadedness, weakness, blurred vision, and fatigue upon standing.
Other predominantly orthostatic symptoms include palpitations, tremulousness, and anxiety.
Slide81Clinical POTS
Gastrointestinal symptoms such as nausea, abdominal cramps, early satiety, bloating, constipation, and diarrhea may be particularly problematic in some.
There may also be evidence of venous pooling, as manifested by
acrocyanosis
and edema when upright.
Syncope is relatively unusual, but does occur in about 40 percent of patients.
Slide82Slide83Clinical POTS
The
onset often follows a
flulike illness
.
I
llness
may occasionally
represent a
self-limited
autoimmune disease.
The
role of immune
and epigenetic
factors remains
ill defined.
Some
patients have an
insidious onset
over years, sometimes
with a
past history of
VVS.
Slide84Clinical POTS
? Some
patients have joint hypermobility syndromes.
Causality is unclear.
While supine or seated, some patients appear well, others pasty pale.
Slide85Clinical POTS
Patients are unable to remain
upright for
long periods of
time.
Symptoms
are similar to
the
prodrome
of
VVS
.
BP
is typically well maintained
and may
increase when upright
in
hyperadrenergic
individuals.
Prolonged laboratory
tilt may
provoke VVS.
Slide86Clinical POTS
Cognitive deficits and exercise intolerance are prominent complaints.
Gastrointestinal symptoms include
dysmotility
issues.
Young women may be underweight, and POTS must be differentiated from eating disorders, which can produce POTS-like
Orthostatic Intolerance
in early stages.
Slide87Clinical POTS
Environmental
heat reroutes
blood to
the skin and makes
patients worse
.
Air-conditioning
may be
required and
standing hot
showers untenable.
Schoolwork
may be impaired.
Home schooling
is
common in adolescents.
Colleges are often
accommodating because
of adaptive
scheduling and
improved logistics.
Slide88Clinical POTS
The symptoms may appear abruptly, often after a viral illness; others experience a more insidious onset.
The severity of symptoms is also quite variable.
Some patients experience only mild symptoms and often only in the setting of additional orthostatic stress (e.g., menstrual cycle, relative dehydration).
Others are profoundly incapacitated.
The course of the disorder may be self limited or may follow a relapsing remitting course over several years.
Slide89Diagnosis POTS
The characteristic autonomic abnormality in patients with postural tachycardia syndrome (POTS) is an exaggerated increase in heart rate on tilt table testing or standing.
Diagnostic criteria from several laboratories have in common a sustained heart rate increase of greater than 30 beats per minute or an increase to 120 beats per minute or greater within the first 10 minutes of tilt.
There is usually no orthostatic hypotension.
Slide90Diagnosis POTS
Autonomic neuropathies, central
dysautonomias
,
bedrest
deconditioning, side effects of medications, and dehydration can produce similar symptoms to POTS.
Ruling out these conditions is essential to making a diagnosis of POTS.
In most cases, historical information and a neurologic examination specifically looking for other evidence of autonomic failure, neuropathy, and extrapyramidal signs, will provide evidence of the underlying disorder.
Slide91Diagnosis POTS
Patients with POTS may be thought to have panic, anxiety, somatization disorder, or chronic fatigue syndrome in part because of the vague nature of the symptoms.
In fact, patients with POTS report subjective cognitive dysfunction and have objectively increased scores on inattention scales, but do not have an increased prevalence of depression or anxiety.
The prominent postural nature of the symptoms should prompt the clinician to look for the diagnostic heart rate response.
Slide92Diagnosis POTS
The syndrome of inappropriate sinus tachycardia is characterized by an elevated heart rate that is not influenced by postural changes.
Slide93Treatment POTS
The optimal therapy of postural tachycardia syndrome (POTS) is uncertain.
No intervention has been systematically studied.
The placebo effect may be substantial in POTS, highlighting the need for controlled studies.
Exacerbating factors, medications, dehydration, and inactivity should be avoided.
Slide94Treatment POTS
Because many patients with POTS have a low plasma volume, correction with oral volume expansion, a high salt
diet (3,000 mg to 10,000 mg per
day), and fludrocortisone, a mineralocorticoid agonist may improve symptoms.
This regimen is similar to that used in orthostatic hypotension in general.
Slide95Treatment POTS
Some patients report symptomatic benefit with acute ingestion of 16
oz
of water and from a saline infusion of 500 to 2000 cc, corresponding to objective improvement in tilt testing response.
However, it is not clear that this translates to a therapeutic response to chronic treatment.
Fludrocortisone (0.1 to 0.4 mg per day) is most effective when combined with increased salt and water intake.
Treatment may be complicated by supine hypertension, fluid retention, and hypokalemia and should be monitored closely.
Slide96Treatment POTS
Adrenoreceptor
agonists may be helpful in some patients (e.g.,
midodrine
2.5 to 10 mg three times daily).
Both intravenous phenylephrine and oral
midodrine
have been associated with improved symptoms and heart rate response in some patients during tilt testing.
However, benefit from chronic therapy is not established.
Slide97Treatment POTS
Preliminary evidence suggests that the
acetylcholinesterase
inhibitor
pyridostigmine
(30 mg daily) may attenuate the tachycardia and improve symptoms.
Further confirmation from larger trials is needed to establish the benefit of
acetylcholinesterase
inhibition for POTS.
Slide98Treatment POTS
Some patients, particularly those troubled by prominent adrenergic symptoms, may benefit from beta blocking agents.
These should be started in low doses and increased gradually (e.g., propranolol 10 to 20 mg three or four times daily).
In one placebo-controlled, randomized crossover study, a single low-dose of oral propranolol (20 mg) was associated with improved tachycardia and reduced symptoms, while higher dose propranolol (80 mg) was associated with unchanged or worsened symptoms.
Slide99POTS Treatment
Water ingestion is a useful,
short lived palliation.
Effects
are
through TRPV4
receptors in the
splanchnic vasculature.
Sixteen
ounces
of water
and waiting 20 to 30
minutes yields
benefit for
hours.
Salt
and water loading can
help but
often require Spartan
efforts.
Slide100POTS Treatment
Even when the cause is known
pharmacologic
treatment is rarely curative.
Most young people improve over time. In some, POTS persists.
Slide101Volume Expansion
Fludrocortisone
0.05-0.2 mg daily – Many patients with POTS
are hypovolemic
4, so fludrocortisone (an aldosterone analogue) is often used.
Through enhanced
renal sodium retention, it should expand the plasma volume (although
the data
are poor). Potassium wasting can result in hypokalemia, so serum K+
should be
monitored periodically.
Slide102Sympatholysis
Propranolol 10-20 mg PO QID – Many patients report intolerance to
beta blockers when
first seen at the Vanderbilt Autonomic Dysfunction Center. The
vast majority
of POTS patients, however, respond well hemodynamically
and symptomatically
to low doses of
propranolol.
Of note, more complete
beta blockade with
higher doses of propranolol cause symptoms to worsen. Long
acting propranolol
was not found to be
helpful.
Slide103Sympatholysis
Methyldopa 125mg QHS-BID – Methyldopa is a false neurotransmitter that
can lower
central sympathetic tone. It is particularly useful in
hyperadrenergic
patients.
Clonidine
0.05-0.2 mg PO BID (or a long acting patch) - Alpha 2
adrenergic agonist
that acts centrally to decrease sympathetic nervous system tone. It
can stabilize
HR and BP, but it can also cause drowsiness, fatigue and worsen
the mental
clouding of some patients.
Slide104Vasoconstrictor Therapy
Midodrine
5-10mg PO q4H x3/day - Since a failure of vascular resistance may
be an
integral part of neuropathic POTS, vasoconstrictors such as
midodrine
(
alpha-1 agonist
) can be
employed.
Slide105Increasing Vagal Tone
Pyridostigmine
30-60 mg PO TID –
Pyridostigmine
is a
peripheral
acetylcholinesterase
inhibitor. By increasing synaptic acetylcholine at both
the autonomic
ganglia and the peripheral muscarinic parasympathetic
receptors,
pyridostigmine
significantly restrains the heart rate in response to standing
in patients
with
POTS.
Pyridostigmine
is most effective in combination
with low
dose propranolol. Since
pyridostigmine
enhances bowel motility, it is often
not well
tolerated in patients with diarrhea-predominant irritable bowel
syndrome symptoms.
Slide106? Treatment of POTS
Cardiovasc
Ther
. 2014 Feb 4.
doi
: 10.1111/1755-5922.12067. [
Epub
ahead of print]
Melatonin reduces tachycardia in Postural Tachycardia Syndrome (POTS): A Randomized, Crossover Trial.
Green EA1, Black BK,
Biaggioni
I,
Paranjape
SY,
Bagai
K,
Shibao
C,
Okoye
MC,
Dupont
WD, Robertson D, Raj SR.
Autonomic Dysfunction Center, Division of Clinical Pharmacology, Departments of Medicine, Vanderbilt University, Nashville, Tennessee, USA.
Slide107Figure. Treatment strategies for POTS.
Grubb B P , and Karabin B
Circulation
. 2008;118:e61-e62
Copyright © American Heart Association, Inc. All rights reserved.
Slide108POTS Treatment
One confounding and alarming
issue is
the tendency for POTS patients
to bed rest
.
Prolonged bed rest emulates microgravity
and has deleterious
effects including Orthostatic Instability (OI)
profound reductions
in blood
volume and cardiac size,
redistribution of
blood, osteoporosis,
skeletal muscle
pump atrophy, and
more.
Vasoconstriction is impaired.
Bed rest causes
a self-perpetuating state of
OI, which
can emulate or intensify POTS.
Slide109POTS Treatment
It is paramount for POTS patient to leave bed and recondition.
Well-structured exercise protocols are essential and must accommodate patients who start off bed rested.
Reconditioning invariably improves patient well-being. Recent work supports the idea that POTS patients are also exercise deconditioned compared with matched volunteers.
Although
exercise deconditioning may or may not be causal in POTS, it is clear that exercise reconditioning is beneficial and should be advocated for all POTS patients.
Slide110Diagnostic Criteria for Postural Tachycardia Syndrome
HR increase ≥30 bpm from lying to standing
Absence
of significant drop in BP with standing
Positional
symptoms
○ Many symptoms are worse with upright posture and improve on lying down
○ Some symptoms can be non-positional (e.g. fatigue, headache)
Chronic
symptoms
○ Duration ≥6 months
Absence
of other overt cause for tachycardia
○
E.g.,
acute blood loss, prolonged
bedrest
, hyperthyroidism, tachycardia promoting medications
Slide111Slide112Reflex (Neurally Mediated) Syncope
Reflex (
neurally
mediated) syncope is a transient loss of consciousness due to a reflex response that encompasses vasodilatation and/or bradycardia (rarely tachycardia), leading to systemic hypotension and cerebral
hypoperfusion
.
Types of reflex syncope include vasovagal syncope, situational syncope, carotid sinus syncope, and atypical forms (without apparent triggers and/or atypical presentation).
Slide113Reflex Syncope
Vasovagal:
Mediated by emotional distress: fear, pain, instrumentation, blood phobia
Mediated by orthostatic stress
Slide114Reflex Syncope
Situational:
Cough, sneeze
Gastrointestinal stimulation (swallow, defecation, visceral pain)
Micturition (
postmicturition
)
Post-exercise
Postprandial
Others (e.g., laughter, brass instrument playing, weightlifting)
Hair grooming
Stretching
Slide115Reflex Syncope
Carotid sinus syncope
Atypical forms (without apparent triggers and/or atypical presentation)
Slide116Reflex Syncope
Vasovagal syncope (also known as
neurocardiogenic
syncope) is the most common cause of syncope.
The diagnosis may be suggested or diagnosed by a specific history with well-known triggers, but a classic history is not required.
The diagnosis can also be made by exclusion of other causes of syncope and by a characteristic response to upright tilt table testing during which the patient may pass out from bradycardia and/or hypotension.
Slide117Slide118Reflex Mechanism - Bezold Jarisch
Chang-Sing P.
Cardiol
Clinics. 1991;9(4):641-651
Inotropy
Contractility
Venous return
Trigger
BP
Sympathetic
tone
Arterial
tone
BP
HR
Vasodilation
BP
Syncope
Vagal
efferent
Small ventricle
Vagal
afferent
Sympathetic
withdrawal
Wall stretch
Reflex
C-fibers
Slide119Reflex Syncope
Upright posture causes pooling of blood in lower extremities
Decrease in venous return causes transient
hyperdynamic
ventricle
Cardiac C fibers (mechanoreceptors) activate causing parasympathetic response resulting in bradycardia, peripheral vasodilation and hypotension
Abrupt decrease in BP and HR ±
asystole
Slide120Reflex Syncope
Alterations in autonomic activation are responsible for reflex syncope. Three types of responses are seen: a
cardioinhibitory
response, a vasodepressor response, and a mixed response with features of both.
Slide121Reflex Syncope
An individual patient may have separate
syncopal
events characterized by a primary vasodepressor,
cardioinhibitory
or mixed responses, but the episodes can vary in their presentation for any individual such that
asystole
may occur at one time and hypotension at another.
Furthermore, the response observed during tilt table testing is not necessarily the same as that recorded during clinical episodes.
Asystolic
pauses are more common during spontaneous episodes, but hypotension is more common during tilt table testing.
Slide122Reflex Syncope
Vasovagal (
neurocardiogenic
) syncope (also known as the “common faint”) refers to a variety of clinical scenarios in which a neural reflex results in usually self-limited systemic hypotension characterized by bradycardia and/or peripheral vasodilation.
It is the most common cause of syncope (approximately 20 to 35 percent of cases), particularly in patients without apparent cardiac or neurologic disease.
However, reflex syncope is the most common cause of syncope even among patients with heart disease and should be considered as a potential cause in such patients.
Slide123Reflex Syncope
Vasovagal syncope is a common cause of syncope in athletes.
However, other potential causes of syncope should be considered and evaluated before identifying the etiology of syncope, particularly if the syncope occurs during exertion.
Athletes with syncope during physical activity should be evaluated for potential risk of sudden death.
Slide124History Reflex Syncope
Clinical presentation — Patients with vasovagal syncope are most commonly young and otherwise healthy.
Typical triggers and premonitory symptoms are strongly suggestive of vasovagal syncope, although these may be absent or difficult to correlate to the
syncopal
episode.
Women and patients younger than 40 are more likely to have typical symptoms.
However, older patients are also frequently diagnosed with vasovagal syncope.
Older individuals have specific triggers that may be absent in younger individuals (i.e., micturition, cough, defecation, deglutition).
Slide125History Reflex Syncope
Vasovagal syncope (“classical”) refers to syncope triggered by emotional or orthostatic stress such as venipuncture (experienced or witnessed), painful or noxious stimuli, fear of bodily injury, prolonged standing, heat exposure, or exertion (post exertion).
Slide126History Reflex Syncope
Vasovagal syncope is often associated with a
prodrome
and persistence of nausea, pallor, and diaphoresis, consistent with increased vagal tone.
Syncope is typically of short duration and occurs in the sitting or standing position.
The supine position restores adequate blood flow to the brain.
Slide127History Reflex Syncope
However, full recovery may be delayed as the patient may feel depressed or fatigued.
This course may help distinguish vasovagal syncope from syncope associated with arrhythmia, which is typically of abrupt onset and of short duration.
Loss of consciousness may be prolonged with some other causes of syncope, such as seizures and aortic stenosis, but rarely with vasovagal syncope
Slide128Tilt Table Testing
T
he tilt table test has limited specificity, sensitivity, and reproducibility.
Slide129Slide130Treatment Reflex Syncope
No therapy has been proven effective for recurrent vasovagal syncope.
Some intuitively appealing therapies have not proven effective.
Therapy is particularly important in patients who have recurrent syncope in high-risk settings (e.g., commercial vehicle driver, pilot) and who wish to continue these activities.
Patients with recurrent episodes may require restriction of activities until therapy is shown to be effective.
Slide131Treatment Reflex Syncope
Explanation — Patients with vasovagal syncope should be provided with reassurance and education regarding the nature, risks, and prognosis of the condition.
The patient should be advised to assume the supine position with legs raised at the onset of symptoms.
The patient should be advised to avoid trigger events when feasible, and medications that may induce hypotension should be modified or discontinued.
A study of self-reported symptom burden in 418 patients diagnosed with vasovagal syncope indicated that 35 percent were symptom free at median five-year follow-up, regardless of presenting symptom or treatment received.
Slide132Treatment Reflex Syncope
Physical
counterpressure
— Studies have found that isometric activity, such as crossing the legs and the arms, may be helpful to offset a
syncopal
response, but release of this position may be associated with precipitous decline in heart rate and blood pressure.
Counter-pressure maneuvers, such as tensing the arms with clenched fists, leg pumping, and leg-crossing may abort a
syncopal
episode or at least delay it long enough that patients can assume the supine position.
Physical
counterpressure
maneuvers are intended to reduce lower-extremity venous pooling and therefore improve cardiac output and prevent vasovagal syncope.
Slide133Treatment Reflex Syncope
Maneuvers include:
■Leg-crossing with simultaneous tensing of leg, abdominal, and buttock muscles.
■Handgrip, which consists of maximum grip on a rubber ball or similar object.
■Arm tensing, which involves gripping one hand with the other while simultaneously abducting both arms
Slide134Treatment Reflex Syncope
Evidence from clinical trials suggests a limited role for pacemaker therapy in patients with vasovagal syncope.
Slide135Treatment Reflex Syncope
Some have recommended support stockings (in some cases,
Jobst
stockings), volume expansion by liberalizing salt intake, and occasionally administration of the mineralocorticoid fludrocortisone (similar to the regimen used in the treatment of orthostatic hypotension).
Data are lacking to support this approach in treating reflex syncope.
Slide136Treatment of Reflex Syncope
Beta blockers
Although beta blockers have been the most commonly used drug therapy for vasovagal syncope, available evidence does not support their efficacy.
They have been postulated to act upon the ill-defined afferent limb of the reflex arc involved in the
Bezold-Jarisch
reflex and to potentially also inhibit the discharge frequency of the C fibers originating from the cardiac mechanoreceptors and chemoreceptors.
Slide137Treatment Reflex Syncope
■
Midodrine
, an alpha-1-adrenergic agonist, had a beneficial effect in a small randomized trial and a number of observational studies.
The benefits have ranged from prevention of
syncopal
episodes in 95 percent of previously untreated patients to efficacy for up to 22 months in as many as 78 percent of patients who failed to respond to a beta blocker or other conventional therapy.
However, the efficacy of
midodrine
is uncertain, and another alpha agonist,
etilefrine
, was ineffective in a placebo-controlled study of 126 patients
Slide138Treatment Reflex Syncope
Some patients with vasovagal syncope respond poorly to general measures. Orthostatic or tilt training may be an effective approach, although study results have been mixed.
Slide139Treatment Reflex Syncope
The efficacy of orthostatic training started in hospital and continued at home was suggested by a controlled but non-randomized study. Forty-seven patients with recurrent syncope and a positive upright tilt table test who were refractory to traditional therapies were assigned to a tilt-training program or to continued medical therapy, depending upon their consent. The training program included five daily in-hospital upright tilt table studies increasing in duration from 10 to 50 minutes. The training program was continued at home with the patient instructed to stand against a wall for up to 40 minutes twice a day, under supervision of a family member.
Slide140Treatment Reflex Syncope
Wall stands with progressive
increase in
time over 6 to 8 weeks can improve symptoms, possibly by retraining
baroreceptor reflexes. While
the individual is standing, the upper back is positioned against
a wall
without arm and leg movement, beginning with 5-minute intervals twice
daily and
increasing gradually to 30-minute to 40-minute intervals over 6 to 8 weeks.
Slide141Treatment Reflex Syncope
Moderate exercise training — Limited uncontrolled data suggest that moderate exercise training may increase orthostatic tolerance in patients with syncope.
Slide142Driving Restrictions
The 2009 ESC guidelines recommend no restriction with a single mild episode of vasovagal syncope in a private driver.
If there are recurrent and severe episodes, private drivers are allowed to return to driving after symptoms are controlled.
For a professional driver, no restriction is recommended for a single mild episode, unless it occurs during high-risk activity.
For recurrent and severe episodes, permanent restriction is recommended unless effective treatment has been established.
Slide143References
Vanderbilt
Autonomic Dysfunction
site (
www.mc.vanderbilt.edu/gcec/adc
)
http://
www.dysautonomiainternational.org
DOI:
10.1542/peds.2012-2610 Pediatrics
2013;131;968; originally published online April 8,
2013; Julian
M. Stewart Common Syndromes of Orthostatic
Intolerance
Postural Tachycardia
Syndrome: A
Heterogeneous and Multifactorial
Disorder Eduardo
E.
Benarroch
, MD,
DSc
Mayo
Clin
Proc
. 2012;87(12):1214-1225
Slide144