What is a complete heart block?
Failure of the AV node to transmit an electrical pulse causing the heart beat to be disrupted
What are the structural abnormalities?
- Fibrosis of the AV node
- Necrosis/infarction of the AV node due to coronary artery disease)
What happens in a complete heart block?
- Failure of the AV node to transmit an electrical impulse to the ventricle
- this causes the atria to contract independently of the ventricles
- the ventricles develop their own pacemaker activity
What causes a complete heart block?
-taking a beta-blocker or other rate-lowering drugs, such as digoxin and verapamil, that act to block the AV node. These are most common in elederly people who previously has had a myocardial infarction
What are the two types of complete heart block and how do they present?
- Chronic heart block, presents gradually and in isolation (tiredness and breathlessness with exercise)
- Acute heart block, presents suddenly with other symptoms (light headedness or collapse with loss of consciousness)
What are the signs and symptoms of a complete heart block?
- tiredness and breathlessness with exercise (chronic complete heart block)
- light headedness or collapse with loss of consciousness (acute complete heart block)
- chest pain
- heart rate/pulse is slow (
What are the abnormal test results?
?
What is the medical/surgical intervention?
- the ambulance/paramedic staff may administer atropine
- a temporary pacemaker introduced immediately in hospital
How does atropine work?
-it blocks the vagus nerve and acetylcholine allowing the heart rate to rise
What is the secondary prevention?
-a permanent pacemaker if heart block persists after recovering from associated myocardial infarction an after stopping heart rate lowering drugs
