heart block

Question 1

what are the causes of bradycardias?

Answer 1

DIVISIONS

D- drugs- ABCD
I- ischaemia/infarction - inferior MI
V- vagal hypertonia- athletes, vasovagal syncope, carotid sinus syndrome

I- infection- viral myocarditis, rheumatic fever, IE

S- sick sinus syndrome

I- infiltration- restrictive/dilated cardiomyopathy - autoimmune, sarcoid, haemochromatosis, amyloid, muscular dystrophy

O- hypothyroidism, hypokalaemia, hypothermia

N- neuro- increased ICP

S- septial defect- primum ASD
surgery or catherisiation

Question 2

what is sick sinus syndrome?

Answer 2

structural damage or fibrosis of SA node, AV node or conduction tissue

presents with SVT alternating with either sinus bradycardia +/- arrest or SA/AV block

Question 3

how do you treat sick sinus syndrome?

Answer 3

if bradyarrhythmia- pace
if tachyarrhythmia- amiodarone

Question 4

what is first degree heart block

Answer 4

prolonged delay between atrial + ventricular epolarisation (>200ms) -> prolonged PR interval

1:1 relationship between p-wave + QRS complex maintained
no real symptoms- treatment not necessary

Question 5

what is second degree mobitz type 1 wenckebach heart block

Answer 5

radual lengthening of PR interval until QRS is blocked -> some p waves arent followed by QRS complex

minimal symptoms- atropine if symptomatic

Question 6

what is second degree heart block- mobitz type 2

Answer 6

loss of AV conduction without lengthening of PR interval- PR interval is fixed
block may last for 2 or more beats

Question 7

what is treatment of type 2 second degree heart block?

Answer 7

pacemaker

Question 8

what is third degree heart block

Answer 8

complete AV-conduction failure
no P:QRS relationship
reduced cardiac output- disordered contraction of atria + ventricles

treatment- pacemaker