Syncope Flashcards
Cohort and population based studies suggest that around __% of the adult population has experienced a syncopal episode. Usually described as a “faint” or “blackout” or “Collapse”
40%
What gender is more likely to report syncope
women
Syncope incidence is higher with:
- advancing age
2. prescription of vasoactive drugs and cardiac arrhythmias
Describe the bimodal distribution of syncope based on age
- in adolescents and young adults a reflex mechanism is the most common
- above the age of 65 a cardiac cause or orthostatic hypotension should be suspected
Syncope is a transient loss of consciousness (T-LOC) due to ___
transient global cerebral hypoperfusion
Syncope is characterized by
- rapid onset,
- short duration, and
- spontaneous complete recovery
- episode typically lasts 20-30 seconds and almost invariable less than 5 min
It is important to distinguish Syncope from other causes of T-LOC (Transient Loss of Consciousness). Some of these other causes are:
- Pre-Syncope: lightheadedness without LOC
- Drop Attack: loss of posture without LOC
- Coma: LOC without spontaneous recovery
- Seizure: Tonic-Clonic Movements that start WITH LOC (vs hypoxic myoclonus which can occur with syncope), post-ictal recovery period
- Hypoglycemia
- Hypoxia
- TIA – NO LOC
- Cardiac Arrest
What is the most common type of syncope and the most dangerous type
Most common: reflex syncope (neurocardiogenic/vasovagal)
Most dangerous: cardiovascular
What are different etiologies of syncope
- Neurally-mediated (reflex syncope) (most common)
- Cardiovascular (most dangerous)
- orthostatic hypotension (D-A-A-D)
Causes of Neurally-mediated (reflex syncope)
- Pain/Noxious Stimuli
- Situational (micturation, cough, defecation)
- Carotid Sinus Hypersensitivity (CSH)
- Fear
- Prolonged standing / heat 5. exposure
Causes of cardiovascular syncope
- Arrhythmia – Tachy or Brady
- Valve Stenosis (outflow obstruction)
- HOCM (outflow obstruction)
Causes of orthostatic hypotension syncope
D-A-A-D
- Drugs (Vasodilator / volume Depletion): BP meds, Diuretics, TCAs
- Autonomic Insufficiency (Parkinsons, Shy-Dragger, DM, Adrenal Insufficiency)
- Alcohol
- Dehydration
‘Vasovagal’ syncope (VVS), also known as the ‘common faint’ is mediated by:
emotion or by orthostatic stress
e.g. fear, pain, blood phobia
‘Vasovagal’ syncope (VVS) is usually preceded by:
prodromal sx of autonomic activation: sweating, pallor, nausea
___ traditionally refers to reflex syncope associated with some specific circumstances.
Situational’ syncope
ex. cough, sneeze, GI Stimulation (swallow, defecation, visceral Pain), Urination, post-prandial, weightlifting, Laughter, brass instrument playing
___ syncope can occur in young athletes as a form of reflex syncope as well as in middle-aged and elderly subjects as an early manifestation of ANF before they experience typical OH
Post-exercise
*type of situational syncope
What is carotid sinus syncope
In its rare spontaneous form it is triggered by mechanical manipulation of the carotid sinuses. In the more common form no mechanical trigger is found and it is diagnosed by carotid sinus massage.
*type of reflex syncope
Types of reflex syncope
- Vasovagal syncope
- situational syncope
- carotid sinus syncope
- “atypical” syncope
The term ___ is used to describe those situations in which reflex syncope occurs with uncertain or even apparently absent triggers.
‘atypical form’
how do you dx atypical syncope
rests less on history taking alone, and more on the exclusion of other causes of syncope (absence of structural heart disease) and on reproducing similar symptoms with tilt testing
How does orthostatic hypotension syncope occur
- ANF sympathetic efferent activity is chronically impaired so that vasoconstriction is deficient.
- Upon standing, BP falls and syncope or pre-syncope occurs.
What changes in BP need to occur for OH syncope
usually defined as a decrease in systolic BP >=20 mm Hg or a decrease of systolic BP to <90 mm Hg (associated with syncope or pre-syncope).
____ refers to symptoms and signs in the upright position due to a circulatory abnormality.
Orthostatic intolerance’
Symptoms of Orthostatic intolerance
- syncope
- dizziness/ LH, pre-syncope;
- weakness, fatigue, lethargy;
- palpitations, sweating;
- visual disturbances (including blurring, enhanced brightness, tunnel vision);
- hearing disturbances (including impaired hearing, crackles, and tinnitus)
Clinical features that can suggest a reflex mediated syncope on initial evaluation
- Absence of heart disease
- long hx of recurrent syncope
- after sudden unexpected unpleasant sight, sound, smell or pain
- prolonged standing or crowded, hot places
- N/V associated w. syncope
- during meal or post-prandial
- w/ head rotation or pressure on carotid sinus (as in shaving or tight collars)
- after exertion
Clinical features that can suggest a OH mediated syncope on initial evaluation
- after standing up
- temporal relationship w/ start or changes of dosages of vasodepressive drugs leading to hypotension
- prolonged standing, esp. in crowded, hot places
- presence of autonomic neuropathy or Parkinsonism
- Standing after exertion
___ are the most common cardiac causes of syncope. They induce hemodynamic impairment, which can cause a critical decrease in CO and cerebral blood flow.
Arrhythmias
examples of arrhythmias that can cause syncope
- Bradycardia
- sinus node dysfunction
- AV Conduction system disease – Heart block
- Implanted device dysfunction - Tachycardia –
- Supraventricular
- Ventricular (idiopathic, secondary to structural heart disease or channelopathies) - Drug induced - antiarrhythmic drugs, QT prolonging drugs
What structural cardiovascular diseases can cause syncope
- valvular disease
- AMI
- HCM
- Cardiac masses
- pericardial disease/tamponade
- prosthetic valve dysfunction
- PE
- aortic dissection
- PHTN
____ can cause syncope when circulatory demands outweigh the impaired ability of the heart to increase its output.
Structural cardiovascular diseases
The syncope work-up should determine
who is at HIGH RISK for a dangerous short-term cardiac event
The basic work up all syncope patients should get:
- History/Physical including Orthostatics
- Medication Review
- ECG.
- If age over 40, consider Carotid Sinus Massage to assess for Carotid Sinus Hypersensitivity
**CONTRAINDICATED if carotid bruit present or recent TIA/Stroke
+ Test = bradycardia, hypotension, transient pause/asystole, or prodrome symptoms - All patients should then be Risk Stratified
Who is at high risk for short term cardiac mortality and need appropriate cardiac work-up as an INPATIENT:
- Evidence of significant heart disease (such as HF, low LV EF, structural abnormality, or previous MI)
- Clinical (eg palpitations or syncope on exertion or supine)
- family history of sudden cardiac death or non sustained VT
- Hypotension (systolic less than 90 mmHg)
- ECG features suggesting arrhythmia or otherwise abnormal
- Comorbidities such as severe anemia or electrolyte disturbance
What is the work up for syncope in high risk people
- Echo,
- Stress test, and/or
- Ischemic Evaluation
**Carotid Ultrasound has POOR utility in the workup of Syncope and should not be ordered routinely.
Identify patients at high risk for short term events, these patient’s should be
hospitalized and monitored on telemetry while you continue your cardiac workup
Who are low risk patients w/ syncope
Patient’s with no High risk characteristics and/or with highly suspected Reflex or OH Etiology
*Single Episode: No further workup indicated
Additional treatment may be necessary in low risk unpredictable and frequent syncope. In particular when:
- Very frequent syncope alters quality of life
- Recurrent syncope without, or with very short prodrome exposes patients to risk of trauma
- Syncope occurs during high risk activity (e.g. driving, machine operation, flying, competitive athletics, etc.)
How can syncope be evaluated as outpatient?
Multiple Episodes: Can workup as outpatient
- Patient having FREQUENT Episodes: Holter Monitor or Event Monitor
- Patient having INFREQUENT Episodes: Implantable Loop Recorder
- +/- tilt table test— falling out of favor due to poor reproducibility and low sen/
- EP Studies are also an option for rare or difficult to diagnose cardiac syndromes
Neurological Causes of true Syncope
- bilateral carotid or basilar artery disease
- non-convulsive seizue
*Rare
When is head CT indicated for syncope
ONLY if the patient has or experienced focal neurological deficits or they experienced head trauma from the event.
Posterior Circulation evaluation with CTA/MRA or Ultrasound is useful only if ___ is suspected
Vertibro-basilar insufficiency
how does Vertibro-basilar insufficiency typically present
- dizziness
- gait instability
- blurry vision
- nystagmus or
- frank coma
Treatment of reflex syncope and orthostatic intolerance
- Education regarding awareness and possible avoidance of triggers (e.g. hot crowded environments, volume depletion)
- Early recognition of prodromal symptoms (Tilt table testing can be employed to teach the patient to recognize early prodromal symptoms.)
- Performing maneuvers to abort the episode [e.g. supine posture, physical counter pressure maneuvers )PCMs – e.g. leg crossing and squatting)
- If possible, triggers should be addressed directly, such as cough suppression in cough syncope
- Careful avoidance of agents that lower BP (including a-blockers, diuretics, and alcohol) is important
The cornerstone of the non-pharmacological management of patients with reflex syncope is ___ and ___ regarding the benign nature of the condition
education and reassurance
Treatment of OH
- In the absence of HTN, take sufficient salt and water intake, targeting 2–3 L of fluids per day and 10 g of NaCl.
- Rapid cool water ingestion is reported to be effective in combating orthostatic intolerance and post-prandial hypotension.
- Sleeping with the head of the bed elevated (108) prevents nocturnal polyuria, maintains a more favorable distribution of body fluids, and ameliorates nocturnal HTN.
- Gravitational venous pooling in older patients can be treated with abdominal binders or compression stockings.
- Rx: Midodrine (5–20 mg, three times daily)–a-agonist
Key DDX for syncope
- Neurogenic / Reflex - most common
- Cardiac – HIGH RISK PATIENTS, most dangerous
- Orthostatic – “D A A D”
- Other - Neurologic, Functional, Psych
Key points of workup and risk stratification
- H/P, Orthostatics, Meds, ECG, +/- Carotid Massage
- Risk Stratify
- High Risk - Admit w/ cardiac work-up
- Low Risk - Outpatient workup based on frequency of episodes - Brain Imaging ONLY if focal Neuro Deficits or Head trauma
What patients with syncope need to be referred to a specialist
Patients with suspected cardiac syncope or atypical neurally mediated syncope (particularly with injury or driving or occupational related implications)
