Cardiology: L10 Syncope

Syncope

Transient loss of consciousness that is abrupt and short followed by complete spontaneous recovery

Presyncope/Near-Syncope

- sensation of impending loss of consciousness or lightheadedness usually w/ blurred vision

- includes the prodromal sx of syncope without loss of consciousnes

Syncope Etiologies (3)

- Neural mediated (60%)

- Cardiovascular (15%)

- Orthostatic hypotension (15%)

Syncope Patho

- transient global cerebral hypoperfusion

- inadequate blood volume reduced HR/CO --> vasodilation

- decreased sympathetic tone and increased vagal stimulation

Neurally Mediated Syncope 3 types

- Vasovagal "common faint"

- Situational

- Carotid Sinus Hypersensitivity

Vasovagal Reflex Syncope (4)

- certain triggers

- pain, sight of blood, blood drawn by needles, extreme emotional distress

- bradycardia, vasodilation

- decrease in cerebral perfusion

Vasovagal Reflex Syncope: Abnormal autonomic reflex

increased parasympathetic activity and decreased sympathetic activity

Vasovagal Reflex Syncope: CV response (4)

- decreased HR

- peripheral vasodilation

- decreased BP

- decreased CO

Situational Syncope

- specific localized stimuli

- violent coughing, prolonged standing, hot places, micturition, defecation, laughing, lack of sleep, hunger

Carotid Sinus Hypersensitivity Syncope

- mc in elderly

- pressure on the carotid sinus triggers an exaggerated baroreceptor reflex

- increase vagal activity and/or decreased sympathetic activity

Carotid Sinus Hypersensitivity Syncope triggers

- neck movements

- wearing neckties

- shaving

Carotid Sinus Hypersensitivity Syncope dx

Carotid sinus massage with continuous ECG and BP monitoring

When should you avoid a carotid sinus massage

If pt has carotid bruit or known significant carotid stenosis/recent stroke or TIA

Carotid Sinus Hypersensitivity Syncope tx (2)

- avoid known triggers

- review medications that lower HR or BP

Carotid Sinus Hypersensitivity Syncope: Cardioinhibitory form with recurrent syncope tx

Pacemaker

Neurally Mediated Syncope Typical sx (5)

- lightheadedness/dizziness

- nausea

- diaphoresis and pallor

- visual or auditory changes

- may have palpitations

Neurally Mediated Syncope Episode sx (3)

- brief loss of consciousness

- usually < 1min

- spontaneous, rapid recovery

- brief abnormal movements or urinary incontinence

Neurally Mediated Syncope dx (3)

- clinical: trigger + prodrome + brief LOC + rapid recovery

- Tilt table testing (if dx unclear)

- rhythm monitoring (if arrhythmia suspected)

Does a classic vasovagal history usually require extensive testing?

No

Neurally Mediated Syncope tx 1st line (3)

- education and trigger avoidance

- increase fluids and salts (increase intravascular volume and preload)

- counterpressure maneuvers (increase venous return and BP)

Counterpressure Maneuvers ex (2)

- leg crossing/muscle tending

- squatting

Neurally Mediated Syncope: Recurrent sx tx (2)

- Midodrine (a-agonist)

-Fludrocortisone (Na/H2O retention)

Neurally Mediated Syncope: Recurrent syncope + documented cardioinhibitory/asystolic episodes tx

Pacemaker

Neurally Mediated Syncope: How does tx work?

Increasing volume/preload, vascular tone, and preventing excessive bradycardia

Orthostatic Hypotension - why does it happen

- sustained BP decreases within 3min of standing

- baroreflex is inadequate resulting in decreased BP and cerebral perfusion

Orthostatic Hypotension DBP and DBP drop

- decrease SBP ≥ 20 mmHg

- decrease DBP ≥ 10 mmHg

Orthostatic Hypotension sx (6)

- sx after assuming an upright position and generally improve with sitting or lying down

- lightheadedness/dizziness after standing

- blurred or dimmed vision

- weakness/fatigue

- presyncope or syncope

- "coat-hanger" neck/shoulder pain from hypoperfusion

Orthostatic Hypotension Causes (5)

Not enough volume OR not enough vasoconstriction

- volume depletion

- medications

- autonomic dysfunction

- adrenal insufficiency

- acute illness/infection

Orthostatic Hypotension tx

- correct dehydration/volume loss

- reduce or discontinue contributing meds

Orthostatic Hypotension nonpharm tx (4)

- rise slowly

- fluids + increased salt

- compression garments

- counterpressure maneuvers

Orthostatic Hypotension: persistent sx tx (2)

- Fludrocorticone

- Midodrine

Postural Orthostatic Tachycardia Syndrome (POTS)

- chronic orthostatic intolerance with excessive tachycardia when upright

- HR increases ≥30 bpm within 10min of standing

- no significant orthostatic hypotension

Postural Orthostatic Tachycardia Syndrome (POTS) sx (6)

- lightheadedness

- palpitations

- fatigue

- exercise intolerance

- brain fog

- presyncope (mc)/syncope

Postural Orthostatic Tachycardia Syndrome (POTS) conservative tx (3)

- increase fluids and salt

- exercise/reconditioning

- compression garments

Postural Orthostatic Tachycardia Syndrome (POTS) pharm tx (5)

- Beta blocker

- ivabrandine

- midodrine

- fludrocortisone

- pyridostigmine

Cardiogenic Syncope

- highest risk category of syncope

- abrupt decrease in cardiac output and cerebral perfusion

Cardiogenic Syncope Causes (2)

- Arrhythmia

- Structural/obstructive heart disease (HOCM)

Think cardiac when syncope is: (5)

- during exertion

- while supine

- sudden with little/no prodrome

- preceded by palpitations or chest pain

- associated with known heart dz, abnormal EKG, or FHx of sudden cardiac death

Cardiogenic Syncope mc Cause

Arrhythmias (bradyarrhythmias, tachyarrhythmias, inherited arrhythmia syndromes)

Cardiogenic Syncope Inherited Arrhythmia Syndromes (2)

- Long QT Syndrome

- Brugada Syndrome

Long QT Syndrome

- prolonged ventricular repolarization

- congenital or acquired

Long QT Syndrome increased risk of what?

Torsades; increased risk with QTc ≥ 500ms

Long QT Syndrome causes (2)

- QT prolonging medications

- electrolyte abnormalities (decreased K, Mg, and Ca)

Long QT Syndrome Clinical Clue

Syncope + Prolonged QT --> think ventricular arrhythmias

Brugata

- inherited cardiac ion-channel disorder

- predisposed to ventricular tachyarrhythmias and sudden cardiac death

Brugata EKG (2)

- coved ST elevation in V1-V2

- followed by inverted T wave

Brugata Clinical Clue

Unexplained syncope + characteristic right-precordial ECG pattern +/- FHx of sudden death

Cardiogenic Syncope Structural Heart Disease: Obstruction to CO (3)

- severe aortic stenosis

- HOCM

- intracardiac mass (myxomia)

Cardiogenic Syncope Structural Heart Disease: Impaired CO (3)

- severe ventricular dysfunction/cardiomyopathy

- MI

- cardiac tamponade

Structural disease predisposes what?

Arrhythmias

Cardiogenic Syncope Structural Heart Disease Clinical Clue

Exertional syncope + murmur/known structural heart disease

Cardiogenic Syncope tx

tx underlying cause

Cardiogenic Syncope: Bradycardia tx

Pacemakes prn

Cardiogenic Syncope: Tachyarrhythmia tx

antiarrhythmic therapy and/or ablation when appropriate

Cardiogenic Syncope: Ventricular arryhtmia/high SCD risk tx

ICD when indicated

Cardiogenic Syncope: Structural dz tx

tx underlying obstruction or cardiac dz

Syncope Initial Evaluation (5)

- detailed HPI

- PE

- Orthostatic BP and HR

- 12lead ECG

- labs if indicated

Syncope Red Flags (7)

- exertional or supine syncope

- sudden LOC with little/no prodrome

- palpitations before syncope

- known SHD/HF

- prior ventricular arrhythmia

- FHx of premature sudden cardiac death

- abnormal cardiac exam

Suspected arrhythmia further testing

ambulatory monitor

Structural dz further testing

Echo

Exertional syncope further testing

Exercise testing

Suspected reflex/autonomic cause further testing

Tilt table

Selected suspected carotid sinus syndrome further testing

Carotid sinus massage