Week 12 Flashcards
Intro to systems
What is inotropy?
Description of the force of cardiac contraction
What is lusitropy?
Rate of myocardial relaxation
What do chronotropic drugs affect?
Change heart rate and rhythm by affecting electrical conduction of the heart
What is an arrhythmia and arrhythmogenesis?
A condition where there are disturbances in the electrophysiology of the heart
What are ectopic foci?
Action potentials arise from sites other than the SA node
What is enhanced normal automaticity?
Increased action potentials from the SN node
How many degrees of conduction block exist?
3
Describe a 1st degree conduction block.
PR interval exceeds 0.2 seconds
Describe a 2nd degree conduction block.
PR interval progressively lengthens until a missing QRS complex is seen
2 types
Describe a 3rd degree conduction block.
Atria and ventricle operate in isolation from one another
What are the classes in the Vaughn-Williams classification?
Ia - Moderate sodium channel blockers
Ib - Weak sodium channel blockers
Ic - Strong sodium channel blockers
II - Beta adrenoceptor blockade
III - Potassium channel blockade
IV - Calcium channel blockade
What is the effect of class I anti-arrhythmics?
Offset or slow rapid depolarisation
What is the effect of beta adrenoceptor blockers?
Positive lusitropy
Positive inotropy
Positive chronotropy
Why are K+ channel blockers not prescribed as often?
High number of adverse drug effects
What is the impact of K+ channel blockers?
Prolong repolarisation
Increase in action potential duration
What is the effect of Calcium channel blockers?
Offset depolarisation of ventricular action potential
Affects the plateau by decreasing the amount of calcium that can enter the cell down the electrochemical gradient
What are the classes of voltage-gated Na+ channels?
A - Closed
B - Open
C - Inactivated
What does pill in pocket strategy refer to?
Medication prescribed to take at home when symptoms arise
What is the most common cardiac arrhythmia?
AF
Give some examples of sodium channel blockers?
Flecainide
Propafenone
Give some examples of Beta1 adrenoceptor blockers
Atenolol
Bisoprolol
Carvedilol
Give some examples of non-selective beta blockers.
Propanolol
Soltalol
What type of drug is amiodarone?
Potassium channel blocker
Give some examples of calcium channel blockers.
Verapamil
Diltiazem
Name some drugs that don’t fit the Vaugn Williams classification
Adenosine
Ivabradine
Digoxin
Atropine
What is atropine?
Muscarinic antagonist
When is atropine used?
Management of beta blocker induced bradycardia and bradycardia after MI
When is ivabradine used?
Management of angina and heart failure
What does ivabradine do?
Inhibits funny current and reduces heart rate
When is digoxin used?
AF and heart failure
What does digoxin do?
Acts as a positive inotrope to increase contractility and thus cardiac output
When is adenosine used?
Terminating re-entrant supraventricular tachycardia
What is adenosine?
Natural nucleoside which binds to the adenosine A1 receptors in the AV primarily
What are the therapeutic options for BP intervention?
Angiotensin-converting enzyme inhibitor
Angiotensin-II receptor blocker
Calcium channel blocker
Thiazide-like diuretic
What do ACE inhibitors do?
Prevent conversion of angiotensin I to angiotensin II
