Syncope

From Ask Dr Wiki

Contents 1 Definition 2 Causes of Syncope 3 Lethal Conditions 4 Workup 4.1 History 4.2 Abnormalities found on EP Testing 5 References

Definition

• Syncope is derived from the Greek words, ‘syn’ meaning ‘with’ and the verb ‘kopto’ meaning ‘I cut’. It is a symptom, defined as a transient, self-limited loss of consciousness, usually leading to falling.
• It a syndrome that is best thought of as being a subset of a broader range of conditions that cause transient loss of consciousness (TLOC).
• Other TLOC conditions include seizures, concussions, and intoxications.

Causes of Syncope

• Neurally Mediated Syncope (Vasovagal, Carotid Sinus Hypersensitivity, and Situational)
• Autonomic Dysfunction
  • Commonly due to medications such as beta blockers, diuretics, vasodilators, and nitroglycerin
  • Can also be due to Amyloidosis, Diabetes, or Parkinson’s disease
• Cardiac Arrythmias
• Structural Cardiopulmonary Diseases
  • Acute MI
  • Hypertrophic Cardiomyopathy
  • Acute Aortic Dissection
  • Pericardial Tamponade
  • Pulmonary Embolism
  • Aortic Stenosis
  • Pulmonary Hypertension
• Cerbrovascular Disease
  • Subclavian Steal
  • Vertebrobasilar TIA which will have brainstem dysfunction such as cranial nerve deficits, swallowing difficulties, dysarthria, paresis, or ataxia

Lethal Conditions

• Long QT Syndrome
• Complete Heart Block
• Post Myocardial Infarction Ventricular Tachycardia
• HOCM
• ARVD
• Anomalous Coronary Arteries

Workup

History

• Prodrome and Recovery from symptoms (nausea, diaphoresis, pallor, aura, cough, posture)
• Circumstances
• Symptom Frequency
• History of Cardiovascular disease
• Medications
• Family History
• Witnesses

Abnormalities found on EP Testing

• Inducible Monomorphic VT
  • Induced in 35% of patients with EF < 40%, and 3% of patients with EF > 40%
• HV Interval > 100 ms
• Procainamide Administration for Interventricular Conduction Delay
• Pacing Induced Infr-Hisian Block
• SNRT > 3000 ms or CSNRT > 600 ms

References

Syncope in Adults. PACE 2006; 29:1160-1169 Guidelines on Management of Syncope. Europace (2004) 6, 467-537