Syncope

• Defined as a sudden, transient loss of consciousness with�inability to maintain postural tone
• Followed by rapid, complete and spontaneous recovery
• 20% and 40%
• Bimodal
• Bilateral hemispheric dysfunction or Reticular Activating System (RAS) dysfunction
• Majority from acute hypo-perfusion
• can be local (cerebral vasoconstriction (SAH) or systemic hypovolemia (diarrhea))�

Types of syncope

• Neurally mediated (reflex) syncope�Also referred to as “vasovagal”
• Situational syncope�Cough, micturition, defecation
• Orthostatic�� Cardiac syncope�� Arrhythmias or structural heart�� Cerebrovascular syncope �

Evaluation of Syncope History

• Prodrome�Warmth, nausea, and dizziness usually suggest�vasovagal�Absence of prodrome(< 5 seconds) usually suggests�dysrhythmia�Chest pain, severe headache, dyspnea, back pain, or�palpitations suggest an ominous cause
• Post event�Patient should wake up within seconds�Prolonged phase indicative of seizure etiology �

Cause other than a simple ‘faint’?

• Syncope with sudden onset without the usual pre-syncopal symptoms
• Syncope with exercise- usually indicates a structural lesion (e.g. IHSS…)
• Syncope with arm exercises- suspect subclavian steal
• Signs of a seizure
• Elderly- people >60 years have 2* the incidence of cardiovascular causes
• Recumbent? – suspect arrhythmia or Stokes-Adams
• With head-turning- suspect carotid hypersensitivity
• Signs or symptoms consistent with a medical condition- MI, PE

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Emergency Medicine Differential Diagnosis (DDx) �

● These are the diagnoses that we must make every effort to identify in the ED:

�○ CARDIOVASCULAR�■ Myocardial infarction (MI)�■ Aortic stenosis (AS)�■ Hypertrophic cardiomyopathy (HOCM)�■ Pulmonary embolus (PE)�■ Thoracic aortic dissection (TAD)�■ Lethal dysrhythmia (VTACH)

�○ NEUROVASCULAR�■ Subarachnoid hemorrhage (SAH)�■ TIA/Stroke �

○ BLEEDING �■ Ruptured ectopic pregnancy�■ Gastrointestinal bleeding (GIB)�■ Ruptured abdominal aortic aneurysm (AAA)

�○ OTHER / BENIGN�■ Everything else!�■ Usually ok for outpatient follow-up �

Evaluation of Syncope ECG

• Low yield: Identify cause in less than 5%�Warranted in all cases of syncope�Noninvasive�Can pick up potentially life threatening disorder�Class 1 Recommendation 2017 ACC/AHA/HRS guidelines �

■ Dysrhythmia�● Ventricular tachydysrhythmias�● Fast supraventricular tachycardias�● Bradycardias

�■ Ischemic changes�● These include ST segment depression, new T wave changes,�new Q waves�● May need workup for acute coronary syndrome, cardoiology�consultation �

■ Prolonged QT Interval�● When QRS-T duration is greater than R-R interval�● Can lead to Torsades de Pointes, a lethal dysrhythmia�● Associated with medications, congenital syndromes

�■ Delta wave�● A slurred upstroke of the QRS in WPW, a pre-excitation�syndrome�● Associated with various tachydysrhythmias�● Usually get ablation therapy by cardiac electrophysiologists�(in cath lab) �

■ Brugada pattern�● A right bundle branch block pattern (RSR’) with downsloping�ST depression in leads V1 and V2�● Associated with a congenital sodium channel defect and�ventricular fibrillation�● Requires an IACD (implantable defibrillator)

�■ Epsilon wave�● An additional terminal wave following the QRS�● Associated with arrhythmogenic right ventricular dysplasia�(ARVD), a congenital condition that also results in ventricular�fibrillation�● Requires an IACD �

■ Signs of right heart strain�● These include an acute right axis deviation, S1Q3T3 pattern,�acute right bundle branch block (RBBB) pattern, deep�symmetric T wave inversions in V1-V4�● Associated with PE

�■ Signs of left ventricular hypertrophy (LVH)�● There are many different criteria. They include high voltages�in the limb leads (lead I: R>14mm, lead avL: R>11mm) and S�wave depth in V1 + tallest R wave height in V5-V6 > 35 mm�● Although LVH is common in some practice settings (e.g.�from poorly controlled hypertension) it should increase�concern for structural heart disease (AS or HOCM)�● Listen for a murmur and consider an echocardiogram �

● For well appearing/hemodynamically stable patients :

�○ Further selective testing only as guided by history, physical examination�and ECG�○ In many cases, not much more required beyond point of care hemoglobin�○ A point-of-care pregnancy test should be performed in all females of childbearing age �

Disposition �

• Disposition should be dictated by risk of adverse event:�● {Discuss SF Syncope rule - CHESS and others} ��