Supraventricular Tachycardia

Basics

Description

  • Rhythm that originates ectopically above the His bundle
  • Heart rate of 100 bpm or greater
  • Irregular narrow complex supraventricular tachycardia (SVT):
    • Atrial fibrillation (AF):
      • Most common form of pathologic SVT seen in the ED
      • 10% of people >75 yr of age with AF
    • Atrial flutter with variable block
    • Multifocal atrial tachycardia
  • Regular narrow complex SVT:
    • Atrial flutter
    • Atrioventricular nodal re-entry tachycardia (AVNRT):
      • 60% of SVT in adults, 70% are female
      • Typically present age 30–40 yr
    • Atrioventricular reciprocating tachycardia (AVRT) involving an accessory pathway
  • Wide complex SVT:
    • Conduction is outside of the normal His–Purkinje system
    • Accessory pathway or a bundle branch block is present
    • More common in younger patients without structural disease
    • Always suspect a ventricular rhythm with a wide complex rhythm
    • Treat as ventricular tachycardia (VT) unless absolutely certain of SVT

Etiology

  • Sinus tachycardia:
    • Acute MI
    • Anemia
    • Anxiety
    • CHF
    • Drug intoxication
    • Hyperthyroidism
    • Hypovolemia
    • Hypoxia
    • Infection
    • Pain
    • Pericardial tamponade
    • Pulmonary embolism
  • Atrial tachycardia:
    • Electrolyte disturbances
    • Drug toxicity (e.g., theophylline)
    • Hypoxia
  • Junctional tachycardia:
    • AV nodal re-entry
    • Myocardial ischemia
    • Structural heart disease
    • Pre-excitation syndromes
  • Wolff–Parkinson–White (WPW) syndrome:
    • Intrinsic accessory pathway
    • Drug and alcohol toxicity
  • Atrial fibrillation:
    • HTN
    • Coronary artery disease
    • Hyper/hypothyroidism
    • Alcohol intake
    • Mitral valve disease
    • Chronic obstructive pulmonary disease
    • Pulmonary embolism
    • Hypoxia
    • Digoxin toxicity
    • Chronic pericarditis
    • Idiopathic AF
  • Atrial flutter:
    • Ischemic heart disease
    • Valvular heart diseases
    • CHF
    • Myocarditis
    • Cardiomyopathies
    • Pulmonary embolism
    • Electrolyte abnormalities
  • Multifocal atrial tachycardia:
    • Hypoxic effects of chronic lung disease
    • Theophylline toxicity

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