AV Block

Question 1

What is 1^ AV block?

Answer 1

Prolonged PR interval (200+ ms) every p followed by QRS

Question 2

1^ AV block
Sx?
Tx?

Answer 2

Asymptomatic = no Tx

Question 3

Drugs causing 1^ AV block?

Answer 3

beta blockers
CCB
Digoxin
block AVN conduction

Question 4

what is 2^ AV block?

Answer 4

some p waves conducted, others aren’t

Question 5

What is Mobitz 1?

Answer 5

also known as weinkeback’s
PR interval progressively longer until a beat (QRS) is dropped

Question 6

What causes Mobitz 1?
Sx and Tx?

Answer 6

Drugs (same as 1^ AV block) + inferior MI

No Tx unless very symptomatic eg. syncope
Tx = pacemaker

Question 7

What is Mobitz 2?

Answer 7

PR interval consistently prolonged (not progressively getting longer) with random QRS dropped

Question 8

What causes Mobitz 2?
Sx and Tx?

Answer 8

Drugs, Inferior MI, Rheumatic fever
May = severe bradycardia + low CO
Syncope, SOB, Chest pain
Tx = pacemaker

Question 9

What is 3^ av block?

Answer 9

AV dissociation
complete heart block, no impulses conducted; atria and ventricles beat independently of each other

Question 10

What is sustaining the heart beat in complete heart block?

Answer 10

ventricular escape rhythm (all cardiomyocytes can start own electrical activity, ventricles realise they’re getting no impulse therefore generate their own to stay alive

SAN (BEST) –> if dysfunctional, AVN takes over –> if dysfunctional, ventricular pacemakers take over (worst, firing rate 20-40 bpm)

Question 11

causes of heart block?

Answer 11

Acute MI, htn, structural heart disease, LYME DISEASE

Question 12

Tx for 3^ av block?

Answer 12

IV atropine + permanent pacemaker

Question 13

what does right coronary artery supply?

Answer 13

AV node