Atrioventricular Block
Overview
Atrioventricular (AV) block occurs due to delayed conduction of an impulse between the atria or ventricles, due to intrinsic or extrinsic causes.
Causes of Atrioventricular Block
Intrinsic
- Idiopathic degeneration
- Myocardial infarction
- Congenital - congenital heart disease, neonatal lupus
- Infiltrative disease - sarcoidosis, amyloidosis, haemochromatosis
- Cardiac procedures - valvular surgery, correction of congenital heart disease, catheter ablation
- Systemic lupus erythematosus
- Myocarditis
Extrinsic
- Physiologic - sleep, athletes
- Autonomic - carotid sinus massage, carotid sinus hypersensitivity
- Drugs - beta blockers, calcium channel blockers, digoxin, adenosine, amiodarone
- Hyperkalaemia
- Hypothyroidism
Physiologic and autonomic causes of AV block tend to result in first degree or Mobitz I heart block, while pathologic causes tend to result in Mobitz II, advanced second degree or complete heart block.
Next Page
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------