L 33 a Syncope

33) Syncope (5 questions)

Syncope (TLOC) = abrupt and transient LOC a/w absence of postural tone, f/b complete and

usually rapid spontaneous recovery

- Usually leads to a fall

- Prevalence increases w/ age

- Classifications:

a) circulation

Reflex: due to excessive vagal tone and impaired reflex control of peripheral

- Vasovagal reflex

- Situational- triggered by micturition, defecation, swallowing, coughing

- Carotid sinus syndrome/hypersensitivity

Orthostatic hypotension (postural): can be drug-induced, primary autonomic

failure (PD, MS), secondary autonomic failure (DM, CKD), volume depletion

b) c) Cardiac: arrhythmia, obstructive cardiomyopathy, structural heart issues

- Conditions that mimic TLOC: seizures, TIA/stroke, sleep disturbances, accidental falls,

metabolic or toxic abnormalities, conversion rxns, hyperventilation, panic attacks

- High risk features: hx of structural heart disease, abnormal ECG,

>60 y/o

- PE: check vitals, orthostatic BP, HR and rhythm, carotids, RR and pattern, hemoccult,

neuro

- Workup: get ECG in all pts w/ syncope

- Admit if high-risk:

- Hx or ECG suggestive of arrhythmic syncope

- Comorbidities

- Fam hx of sudden death

- Hypotension

- Older age

- Severe structural heart disease, congestive HF, or CAD

Vasovagal syncope = the “common faint”

- MCC of reflex syncope & MCC of TLOC of all age groups

- Young and healthy pts

- Classic presentation: syncope precipitated by fear, stress, painful stimuli, fear of bodily

- Dx:

injury a/w prodrome and persistence of nausea, pallor, diaphoresis

- Episode is short and occurs in sitting or standing position

- Classical form dx by hx

- Nonclassical form dx based on exclusion of other causes and +tilt table testing

- Tx: reassurance, assume supine position with legs raised at the onset of prodrome

- Avoid trigger events

- Physical counterpressure: leg crossing with simultaneous tensing of leg, ab, and

glute muscles. Handgrip max strength. Arm tensing

- Midodrine = alpha agonist, ↑peripheral vasoconstriction and ↓venous pooling

- Fludrocortisone and BB minimal benefit2

- SSRIs some benefit in select pts

- Cardiac pacing not 1st-line tx for most pts

Orthostatic hypotension = significant reduction in BP upon standing

- MC in elderly

- Can be symptomatic or asymp.

- Normal physiologic BP response w/ standing: pooling of blood in LE → ↓BP →

compensatory reflex which ↑sympathetic and ↓parasympathetic outflow → ↑PVR,

venous return, and CO

- Due to: impairment of autonomic flexes, marked volume depletion, or med SE

- Sx: generalized weakness, dizziness, lightheadedness, visual blurring, LOC if severe

- Dx: drop in SBP >20, or drop in DBP >10 w/in 2 mins of standing, or sx of cerebral

hypoperfusion

- Workup: detailed med list, recent med hx and potential volume loss, med hx of CHF,

malignancy, DM, alcoholism, evidence of parkinsonism, peripheral neuropathy,

dysautonomia

- CBC and CMP

- Acute tx: replace fluids, stop offending drugs

- Chronic tx: pt ed, increase salt and water intake, avoid precipitating factors, compression

stockings

- Fludrocortisone

- Midodrine, droxidopa

- Pyridostigmine, NSAIDs, caffeine, EPO

Cardiac syncope = most worrisome

- Lack of premonitory sx

- Episodes are commonly exertional or post-exertional

- Injury secondary to falling is common

- MC due to arrhythmias- HR is too slow or too fast to maintain adequate CO and

systemic arterial pressure

- Tachy: SVT, VT, afib

- Brady: 3rd degree block, 2nd degree block, sick sinus syndrome

- ECG abnormalities suggesting arrhythmic syncope:

- Bifascicular block (LBBB or RBBB w/ L anterior or L posterior fascicular block)

- QRS >0.12 sec

- Mobitz I 2nd degree block

- Long or short QT intervals

- Structural etiologies: aortic stenosis, hypertrophic cardiomyopathy, aortic dissection,

ruptured AAA, PE, pulmonary HTN, atrial myxoma, mitral stenosis, MI, pulmonic

stenosis, cardiac tamponade

- Tx: tx arrhythmias with meds, pacemaker, implantable defibrillator, ablation

Ancillary testing:

a) Carotid sinus massage: identifies carotid sinus hypersensitivityb) c) d) e) f) g) h) i) j) 3

- Rare, usually in elderly men or pts w/ hx of irradiation to head/neck

- For pts >40 y/o with unknown cause of syncope after initial eval

- Avoid in pts w/ TIA/stroke in last 3 mo. or carotid bruit

- Diagnostic if syncope is reproduced in the presence of asystole >3 sec and/or fall

in SBP >50

Upright tilt table test: limited spec, sens, and reproducibility. Use for:

- Unexplained single syncopal episode in high-risk setting

- Recurrent episodes of syncope in absence of organic heart disease after cardiac

causes have been excluded

- When of clinical value to demonstrate susceptibility to reflex syncope

- When trying to discriminate b/w vasovagal and orthostatic

- When differentiating syncope w/ jerking movements from epilepsy

- When evaluating pts w/ recurrent, unexplained falls or w/ frequent syncope and

psych disease

ECG monitoring: for pts with clinical or ECG suggesting arrhythmic syncope

- GS for dx of arrhythmic syncope is when correlation b/w sx an documented

arrhythmia is recorded

Electrophysiology study (EPS): can further evaluate for an arrhythmic cause

- Not recommended if normal ECG, no heart disease, and no palpitations

Echo: for dx and risk stratification in pts w/ suspected structural heart disease

- Can dx LV dysfunction, hypertrophic cardiomyopathy, sig aortic stenosis

Exercise testing: for pts who experience syncope during or shortly after exercise

- Careful ECG monitoring during test and recovery period

- Rec for pts at risk or w/ hx of CAD

Cardiac catheterization: for pts w/ suspected cardiac ischemia or infarction to r/o

ischemia-driven arrhythmias

BNP: can distinguish cardiac from noncardiac causes; >300 predicts serious CV

outcomes

Psych eval: if psychogenic pseudosyncope or psych med SE is suspected

- Psychogenic pseudosyncope: episodes last longer than syncope, high frequency

of attacks, lack of recognizable trigger

Neuro testing: if suspect epilepsy, autonomic failure

- EEG, US of neck arteries, CT/MRI brain are not indicated unless a nonsyncopal

cause of TLOC is suspected