Session 10 - Arrhythmias and Drugs Flashcards
what 5 drugs do you use for hypertension
alpha blocker, beta blockers, calcium blockers, diuretics and ACE inhibitors
what are the 2 causes of bradycardia
- sinus bradycardia where the SAN slows down either due to intrinsic or extrinsic factors
- conduction block in the AVN or bundle of His
what causes tachycardia
- ectopic pacemaker activity
- after depolarisation
- re-enter loops
what causes the production of ectopic pacemaker areas
damage to the myocardium e.g. from ischaemia or stretching due to mitral stenosis
what is early after depolarisation
where another depolarisation occurs because the cell has finished repolarising
what is delayed after depolarisation
where another action potential occurs too quickly whist during the rest period
what is supraventricular tachycardia
tachycardia arising due to problems in the AVN or atria
how does VF cause a reduced CO
due to reduced filling
what are the 4 types of anti-arrhythmic drugs
- sodium blockers
- beta blockers
- potassium blocker
- calcium blocker
how do sodium blockers work and give an example of one
block sodium channels during depolarisation so that another action potential can’t occur too soon. they then depolarise in time for the next AP. e.g. lidocaine
how do beta blockers work and give an example of one
block the sympathetic input to the heart e.g. proponalol
how do potassium blockers work and give an example of one
prolong the action potential, lengthening the absolute refractory period e.g. amiodarone
how do calcium blockers work
decrease the slope of APs at the SAN, decrease AVN conduction and decrease force of contraction
give 3 examples of anti-thrombic drugs
heparin, warfarin and aspirin
what does adenosine do
blocks alpha 1 receptors, terminating supraventricular tachycardias
