Arrythmias Flashcards
describe the difference between 1st degree, 2nd degree and 3rd degree heart block.
1st degree - PR prolongation but all QRS conducts
2nd degree
- mobitz type 1: PR prolongation until P wave fails to conduct = absent QRS
- mobitz type 2: random non conduction of P wave i.e. every 3rd/4th QRS absent
- 2:1 - for every 2 P wave conducting, one fails to conduct
3rd degree HB: no association between atrial and ventricular conduction, conduction maintained only by ventricular escape rhythm
how is heart block treated?
1st degree don’t require treatment
mobitz type I - monitor
mobitz type II - pace maker
3rd degree - depends on cause
- atropine
- temporary or permanent pacing
what is the management for SVT?
valsalva manœuvre
carotid massage
immerse face in cold water
IV adenosine 6mg - 12mg - 12mg
cardioversion
what are the ECG features of SVT?
atria beat 150-250bpm
narrow QRS < 3 squares
what are ECG features of atrial flutter?
regular P waves and QRS complexes atria beat 300bpm saw tooth appearance narrow QRS complex HR depends on degree of heart block
what is 2nd degree mobitz type II associated with?
drugs
- amiodarone
- betablockers
- CBB
- digoxin
inferior MI
increased vagal tone
myocarditis
post cardiac surgery for mitral valve repair/ tetralogy of fallot
what is given for prevention of further SVT episodes?
beta blockers
radio frequency ablation
what is a contraindication to adenosine? what is given instead?
asthmatics
verapamil
(used in treatment of SVT)
what are features of wolf-parkinson-whyte syndrome?
short PR interval
wide QRS
slurred uprising delta wave
what are causes of long QT syndrome?
inherited i.e. channelopathies
acquired;
- hypokalaemia, hypocalcaemia hympomagnaesemia
- tramadol, metaclopramide, domperidone
- SAH, ischaemic stroke
- malnutrition
- hypothermia
- drugs: SSRI (citalopram, escitalopram), TCA, amiodarone, flecainide
- acute MI
what is long QT syndrome?
abnormal long QT interval on ECG
> 430 ms in males
> 450 ms in females
how does long QT present?
commonly presents in young people
- syncope
- palpitations
- tachyarrhythmia
- cardiac arrest
what is wolf-parkinson-whyte syndrome?
accessory conduction pathway between the atria and ventricles known as bundle of kent
doesn’t have same rate slowing properties of the AV node so conducts at a much higher rate
how would you identify LBBB and RBBB on ECG?
LBBB - downward deflection on V1
RBBB - upward deflection on V1
(both may have extra deflection due to slow depolarisation of L or R ventricle)
how do you manage L & R bundle branch block?
pacemaker
cardiac resynchronisation if pumping failure + BBB
