Third degree AV block

Background

• Atria and ventricles beat independently from each other
• Congenital or acquired
• Acquired
  • Ischemia
  • Drugs
  • Structural heart disease

Clinical Features

• Dizziness
• Syncope
• Hypotension

Diagnosis

Rhythm_3rdAVblock.png

• No atrial impulses are conducted
  • P waves normal and regular P-P intervals unrelated to slower regular R-R intervals
  • QRS narrow if block above bundle of His
  • QRS wide if block below bundle of His
  • PR variable

Management

• Pacemaker placement

See Also

• ECG (Basics)