SyncopeW. Kissinger

Tintinalli Sixth Edition

Chapter 52

Syncope

. . . . a sudden, transient loss of consciousness associated with inability to maintain postural tone.

Pathophysiology

Final Pathway

Lack of vital nutrient delivery to the brainstem reticular activating system loss of consciousness and postural tone

Pathophysiology

#1 Drop in cardiac output

Decrease in oxygen and substrate delivery to the brain

#2 Vasospasm

Etiology

Cardiac dysrhythmia

Vasovagal reflex-mediated

Orthostatic hypotension

Normal Response

Physical or emotional stress increased sympathetic outflow increase in heart rate, blood

pressure, and cardiac output

Reflex-Mediated Syncope

Abnormal autonomic nervous system reflex

Inappropriate withdraw of sympathetic tone and replacement with increased vagal tone

Vagal hyperactivity

Reflex-Mediated Syncope

VasovagalSituationalCarotid sinus hypersensitivity

Orthostatic Syncope

Insufficient autonomic response

☼Normally☼Upright posture blood shifted to lower

extremity cardiac output drops increase in sympathetic output and decrease in parasympathetic output ↑ HR and PVR ↑ CO and BP

Orthostatic Syncope

Autonomic dysfunction Primary disease process Secondary to the following:

Peripheral neuropathy Medications Spinal cord injury

Orthostatic Hypotension

Defined by the consensus group of the American Autonomic Society as a sustained decrease in blood pressure exceeding 20 mmHg systolic or 10 mmHg diastolic occurring within 3 minutes of upright tilt.

Orthostatic Syncope

Should have recurrence of syncopal symptoms on orthostatic testing

WarningWarning: 5-55% of patients with other causes of syncope have orthostatic hypotension on exam

Cardiac Syncope

Heart is unable to provide adequate cardiac output to maintain cerebral perfusion Dysrhythmias

Associated with underlying structural disease Structural cardiopulmonary lesions

25 y/o presents after a syncopal event with the following EKG

25 y/o presents after a syncopal event with the following EKG

Long QT syndrome

Normal interval is 0.42 seconds

Cardiac Syncope

If caused by a dysrhythmia: Typically sudden (prodromal symptoms lasting

less than 3 seconds) Subjectively lack warning

Underlying Cardiopulmonary Structural Disease

Aortic Stenosis (listen for the murmur) Chest pain, DOE, and syncope

Pulmonary EmbolismHypertrophic cardiomyopathy

Medications

Β-blockers and calcium channel blockers Blunted heart rate response after orthostatic

stress

Diuretics Volume depletion and orthostatic hypotension

Antipsychotics Proarrhythmic properties

Psychiatric Illness

Generalized anxiety disorderMajor depressive disorder

Typically young, repeated episodes, multiple prodromal symptoms and a positive review of symptoms

Neurovascular Syncope

Brainstem ischemia causing a decrease in blood flow to the reticular activating system

S/S of posterior circulation ischemia Diplopia, vertigo, nausea

Question???

25 year old left-handed male presents to the ED after a syncopal event while painting a fence. You note he has unequal blood pressures in his upper extremities (right>left).

Diagnosis?

Subclavian Steal Syndrome

Abnormal narrowing of the subclavian artery proximal to the origin of the vertebral artery

Emergency Department Evaluation

Goal: Identify those at risk for immediate decompensation and those at future risk of serious morbidity or sudden death.

History

Physical Exam

EKG

Easy Task?!?!?!Just rule-out the following: AMI PE aortic dissection cardiac tamponade tension pneumothorax leaking AAA active internal bleeding malignant cardiac arrhythmias ectopic pregnancy SAH carotid artery/vertebral artery dissection air embolism

History

Patient and witnessesPatient and witnessesEvents

Duration/SymptomsPast medical history

MedicationsFamily history

Physical Examination

Trauma without defensive injuriesCardiovascular system

Murmur Unequal blood pressures Orthostasis

Neurologic system Focal neurologic findings

Rectal Exam

History, Physical and EKG. . . .

EKG

Prior cardiopulmonary diseaseAcute ischemiaDysrhythmiaHeart blockProlonged QT

Lab Testing

Dictated by H & P CBC Pregnancy test Electrolytes

Disposition

Should they stay or should they go?

ACEP Task Force Recommendations

Admit patients with syncope and any of the following:

1. A history of congestive heart failure or ventricular arrhythmias 2. Associated chest pain or other symptoms compatible with acute coronary syndrome 3. Evidence of significant congestive heart failure or valvular heart disease on physical     examination 4. ECG findings of ischemia, arrhythmia, prolonged QT interval, or bundle branch block

ACEP Recommendations

Consider admission for patients with syncope and any of the following:

1. Age older than 60 years 2. History of coronary artery disease or congenital heart disease 3. Family history of unexpected sudden death 4. Exertional syncope in younger patients without an obvious benign etiology for the     syncope

Predictors of Sudden Cardiac Death or Significant Dysrhythmia

1. Abnormal EKG2. Age older than 45 years3. History of ventricular dysrhythmia4. History of congestive heart failure

European Heart Journal, May 2003

Development and Prospective Validation of a Risk Stratification System for Patients With Syncope in the ED: The Oesil Risk Score 270 pts (syncope w/u: H&P, 12 lead, glucose,

hgb) followed one year Four independent risk factors: >65 years, hx

cardiovascular dz, syncope w/o prodrome, abnormal EKG

1 (0.8- 8.5%). . . . . . 4 (52.9%)

Academic Emergency Medicine Dec 2003

A Risk Score to Predict Arrhythmias in Patients with Unexplained Syncope <65 years, normal EKG, no Hx of CHF 0 (2%), 1 (17%), . . . . . . 3 (27%)

Questions

1. The most common cause of syncope is A. Orthostatic hypotension B. Vasovagal C. Cardiac dysrhythmia D. Situational

Questions

2. Classic symptoms of orthostatic syncope include all of the following except

A. Blurred Vision B. Dizziness C. Vertigo D. Tunnel Vision

Questions

3. The classic presentation of Syncope from aortic stenosis include.

A. Chest Pain B. Syncope C. Dyspnea on exertion D. Palpitations

Questions

4. Which on of the following criteria according to Tintinalli define Orthostatic Hypotension

A. Increase in HR > 20 BPM B. Decrease in Systolic BP of 10mmHg C. Decrease in Systolic BP of 20mmHg E. A and C F. A and B

Questions

5. T or F Bradycardia is most likely to be a incidental finding in syncope

6. T or F In cardiac syncope the typical prodrome last no more than 3 minutes

7. T or F Subclavian Steal syndrome is more common on the Left

Answers

1. B2. C3. D4. C5. T6. F 7. T