Arrythmias Flashcards
what are the two types of arrhythmias and what difference is there between them?
supraventricular (origin above the ventricle)
ventricular (origin in the ventricle)
name two types of supraventricular arrhythmias
SVT
bradycardia
what arrhythmias are SVT’s?
atrial fibrillation
atrial flutter
ectopic atrial tachycardia
name four ventricular arrhythmias
premature ventricular complexes (PVC)
ventricular tachycardia
ventricular fibrillation
asystole
what is another name for premature ventricular complexes?
ventricular ectopics
name three AV node arrhythmias
AVN re-entry tachycardia (AVNRT)
AV re-entrant tachycardia (AVRT)
AV block
what are the different types of AV block?
1st-3rd degree
what is an ectopic beat?
a beat/rhythm that originates outwith the SA node
what two things can cause an ectopic beat?
altered automaticity e.g. in ischaemia
triggered activity e.g. caused by digoxin
how does re-entry work to cause an arrhythmia?
has more than one conduction pathway, each with different speeds of conduction
name three things that can cause re-entry in the heart
accessory pathway tachycardia (WPW)
previous MI
congenital heart disease
what triggers re-entry?
an ectopic beat
when does an ectopic rhythm take over the intrinsic, sinus rhythm?
when it becomes faster than sinus rhythm
what is triggered activity
when a small depolarisation higher than threshold occurs in phase 3 of the AP causes a sustained train of depolarisations
what mechanism underlies digoxin toxicity, torsades de pointes and hypokalaemia?
triggered activity
name investigations done for arrythmias
ECG (+ exercise ECG + 24 hour recording)
CXR
ECHO
electrophysiological study
what does an ECG look for in arrythmia?
assesses the rhythm
looks for previous MI and pre-excitation
what condition does pre-excitation occur in?
wolff parkinson white
what is an electrophysiological study for arrythmias?
an arrhythmia is induced to study its mechanism and trace it
what effect does inspiration have on heart rate and how?
increases heart rate as it reduces vagal tone
what is bradycardia?
heart rate under 60bpm
who might have physiological bradycardia?
athletes
what drug is used to treat sinus bradycardia?
atropine
what is used to treat sinus bradycardia if there is a haemodynamic compromise?
pacemaker
what is tachycardia?
heart rate over 100bpm
how is sinus tachycardia treated?
treat underlying cause
give beta blockers
how are atrial ectopic beats treated?
beta blockers may help
avoid stimulants i.e. coffee and cigarettes
what causes AVNRT?
a re-entry circuit within the AVN
what makes up acute management of SVT?
increase vagal tone
IV adenosine and IV verapamil
what can be done to increase vagal tone?
valsalva manoeuvre
carotid massage