Flashcards in 9.1: Cardiac Arrthymia Drugs Deck (13):
In cardiac myocytes, which ion has its highest concentration inside the cells?
What happens in each phase of a fast cardiac action potential?
As VGSCs open, Na floods in make the cell positive
K+ starts to leave but Ca2+ also enters resulting in a plateau phase
K+ leaves and the membrane is hyperpolarised
What type of drugs are class 2 anti arrhythmic drugs?
What arrhythmia can amiodarone predispose to?
Torsades de pointes
(Due to QTc prolongation)
What can atropine be used for?
When is digoxin mainly used?
In atrial fibrillation, atrial flutter, heart failure
How does digoxin work?
So intracellular Na accumulates
This inactivated NCX
So intracellular Ca2+ accumulates
This lengthens the cardiac action potential and increases the contractility
What are some precautions with digoxin?
Renally excreted, so CI in renal failure
Narrow TI, can cause hyperkalaemia, so cardiac monitoring necesssary
How is adenosine administered?
Rapid IV bolus with a half life of seconds
What carrythmias can amiodarone be used for?
What are some side effects of amiodarone?
Lots of serious ones
What is the action of class 1 anti arrhythmics?
Na channel blockers
(E.g. lidocaine, flecainide)