Arrhythmias (Yr4) Flashcards
why do horses have a very high vagal tone?
the heart is very large so has a massive reserve volume so needs to constantly be slowed
where is an ECG placed?
positive at heart apex
negative on mid right jugular furrow
what is the P wave?
depolarisation of atrium
what is the QRS complex?
depolarisation of ventricle
what is the T wave?
repolarisation of ventricle
what are some common physiological arrhythmias?
1st and 2nd degree AV block
sinus block
sinus arrhythmias/bradycardia/tachycardia
what happens during 2nd degree AV block?
regular sinoatrial node depolarisation but every 3-4 beat is blocked by the AV node
what will cause resolution of 2nd degree AV block?
increased sympathetic tone
what happens during 1st degree AV block?
prolonged P-R interval but no dropped beats
how does a sinus arrhythmia appear on an ECG?
periodic shortening/lengthening of R-R interval
how would the rhythm of atrial fibrillation be described?
irregularly irregular (trainers in a washing machine)
what is the typically presenting complaints of atrial fibrillation?
poor performance
fading during race
epistaxis
will atrial fibrillation cause cardiac failure?
no, if it is diagnosed with heart failure it is typically secondary to the failure
what horses with atrial fibrillation can be considered for cardioversion?
if the disease is primary
what drug can be used to treat atrial fibrillation?
quinidine sulphate (increases refractory period for atrial cells)
