dysrhythmia Flashcards
Types of triggered activity
EAD and DAD
cause of EAD
re-activation of L - type calcium channels
cause of DAD
overload of intracellular calcium
underlying cause of DAD and EAD
SNS
heart failure
cardiac glycosides can cause what type of triggered activity?
DAD
blocks of conduction:
infarction/ scar
requirements of re-entry
slow conduction
uni-directional block
what current underlies phase 4 (pacemaker potential)
funny current
phase 0 of pacemaker cells:
depolarisation
what ion is responsible for phase 0 of pacemaker potential
calcium
what current is responsible for phase 3 of pacemaker potential?
delayed rectifier potassium current
class 2 beta receptor antagonists block which current?
pacemaker/ funny current
inhibition of which current slows the frequency of electrical activity?
funny current
conduction corresponds to which phase of pacemaker AP
phase 0 (upstroke)
inhibition of sodium and potassium channels has what effect on electrical activity?
slows conduction
how is the refractory period prolonged?
inhibition of K channels
how is triggered activity reduced?
reducing intracellular calcium and L type calcium current
what underlies ectopic beats
funny current
calcium current
intracellular calcium
which tissue do sodium channel blockers act upon?
atrial and ventricular
which AP phase do sodium channel blockers affect?
upstroke (phase 0)
which sodium channel blockers prolong the refractory period and AP duration
1a by opening K channels
what channel state do 1b drugs bind to?
inactive
which sodium channel blockers have the stronges block?
1C
