Complete Heart Block

Question 1

Define syncope

Answer 1

sudden, temporary, loss of consciousness generally caused by insufficient oxygen in the brain through hypoxia or hypotension
(fainting)

Question 2

How long is the average faint?

Answer 2

30 seconds

Question 3

What is complete heart block?

Answer 3

Damage/necrosis of AV node means there is a complete failure of the AV node to transmit electrical impulse from the atria to the ventricles.
Ventricles will then develop their own pacemaker activity at a much slower rate.

Question 4

What drugs can block AV node?

Answer 4

Bea blockers
Digoxin
Verapamil

Question 5

Is complete heart block gradual or sudden?

Answer 5

Can be either

Question 6

Clinical signs

Answer 6

Slow pulse (<60bpm)
Low BP
Cardiac syncope

Question 7

What are some other causes of syncope?

Answer 7

epilepsy (convulsions)
vasovagal fainting (related to context)
tachyarrhthmia
TIA
Hypoperfusion (e.g. due to hypovolaemia)

Question 8

What are the changes in ECG?

Answer 8

No QRS complex
No PR interval
No relationship between P and RS

Question 9

What happens to the P wave on the ECG during complete heart block?

Answer 9

Nothing - normal

Question 10

What happens to the QRS complex on the ECG during complete heart block

Answer 10

non-existant

Question 11

Define asystole

Answer 11

no cardiac electrical activity - no contractions

Question 12

What does a flatline on an ECG show?

Answer 12

Asystole

Question 13

How many seconds of asystole can have serious clinical consequences?

Answer 13

10 seconds

Question 14

What is atropine and why would it be given to treat heart block?

Answer 14

atropine blocks the parasympathetic effect of the vagus nerve and acetylcholine, which slows the heart rate

Question 15

What are the differences in first, second and third degree AV block?

Answer 15

first degree - very small delay in transmission through AV node. no noticeable symptoms.
second degree - series of increasing delays until eventually a heart beat is skipped
third degree - complete heart block (no transmission through AV node)

Question 16

What are the differences in first, second and third degree AV block?

Answer 16

first degree - very small delay in transmission through AV node. no noticeable symptoms.
second degree - series of increasing delays until eventually a heart beat is skipped
third degree - complete heart block (no transmission through AV node)

Question 17

What is the treatment if complete heart block persists after recovery from MI?

Answer 17

Permanent pacemaker