Week 11- Therapeutics for Cardiovascular Disease

Question 1

What two drugs affect myocardial cells directly?

Answer 1

• Antidysrhythmic drugs
• Cardiac glycosides and other inotropic drugs

Question 2

What three drug types affect the cardiac cycle indirectly?

Answer 2

• Drugs acting on the RAAS
• Diuretics
• Calcium Channel Blockers

Question 3

What do class I antidysrhythmic drugs do?

Answer 3

• Blocks Na+ Channels
• Reduces the max rate of depolaristaion during phase 0

Question 4

What do class II antidysrhythmic drugs do?

Answer 4

B-adrenoceptor antagonists, slow SA node and increased refractory period of the AV node

Question 5

What do class III antidysrhythmic drugs do?

Answer 5

• Complex
• Block K+ channels and prolong cardiac action potentials

Question 6

What do class IV antidysrhythmic drugs do?

Answer 6

• Block voltage sensitive Ca2+ channels
• slow conduction in the SA and AV nodes

Question 7

What is the function of lidocaine?

Answer 7

• rapid onset of action
• relatively safe
• first choice treatment of ventricular tachyarrhythmia

Question 8

What is the lidocaine bolus duration of action?

Answer 8

• short duration of action (10-15 minutes)
• continuous rate infusion if required

Question 9

What should you not use lidocaine with?

Answer 9

Do not use lidocaine and adrenaline solutions for injection

Question 10

What is guinidine used for?

Answer 10

Competition horses with atrial fibrillation

Question 11

What does stimulation of Beta Adrenoceptors in the heart by endogenous catecholamines do?

Answer 11

• Increased heart rate in the SA node
• Increased atrial cardiac muscle contractility
• Increased contractility and automaticity of ventricular cardiac muscle
• Increased conduction and automacity of AV valve

Question 12

What do beta- adrenoceptor antagonists do?

Answer 12

• Competitive antagonists
• reduce cardiac O2 filling
• slow HR and improve filling

Question 13

What are atenolol and metaprolol?

Answer 13

Beta 1- adrenoceptor selective antagonists

Question 14

What is sotalol?

Answer 14

Class III- chronic treatments of ventricular and supraventrciular tachyarrythmias- avoid in patients with CHF

Question 15

What is amiodarone?

Answer 15

Primarily Class III action, slow and variable GI absorption, slow onset of action, variable efficacy, high frequency on non-cardiac events
* Monitor plasma K+ events

Question 16

What is sotalol used for?

Answer 16

Chronic treatment of ventricular and supraventricular tachyarrhythmias

Question 17

What is amiodarone used for?

Answer 17

Primary class III action, slow and variable GI absorption, slow onset of action, variable fficacy, high frequency of cardiac events,

Question 18

What is diltazem?

Answer 18

Primarily used for supraventricular tacharrhthmias, atrial tachycardia and flutter. Also used for hypertrophic cardiomyopathy

Question 19

What is verapamil?

Answer 19

Coexistence of atrial fibrillation, with re-entrant may be contraindication for use of these for use of these agents- may exacerbate

Question 20

What is digoxin?

Answer 20

decreases heart rate by reducing the frequency of SA firing and inhibiting AV nodal conduction. Used to treat atrial fibrillation

Question 21

How do you reverse bradyarrhythmia?

Answer 21

Reverses excess vagal activity with atropine or glycopyyrolate
- pacemaker

Question 22

How can you fix a ventricular dysrhythmia?

Answer 22

• Lidocaine
• Procainamide

Question 23

How would you fix a supraventrciular dysrhythmia?

Answer 23

• Digoxin
• Calcium Channel Blockers

Question 24

How would you fix a bradyarrythmia?

Answer 24

• Atropine
• Pacing

Question 25

What is a cardiac glycoside?

Answer 25

* Derived from foxgloves * Increases the force of contraction * slows the heart and incraeses conduction rate through AV node by increasing vagal outflow * Combination of slower HR and increased contraction force increases CO- used to treat heart failure as well as superventricular arrhythmias

Question 26

What is the main caution of cardiac glycosides?

Answer 26

* narrow therapeutic window * may cause excessively low heart rates * cats are more sensitive to toxic effects than dogs

Question 27

What is an inodilator?

Answer 27

* have both a positive inotropic effect and vasodilatory action

Question 28

What is pimobendane?

Answer 28

Phosphodiesterase inhibitor increases intracellular calcium and myocardial oxygenation * used for mitral valve disease

Question 29

What is dobutamine?

Answer 29

* Direct acting synthetic catecholamine with direct Beta adrenergic agonist effects- positively inotropic * used to address hypotension * potent and short acting * produces less tachycardia than other beta agonists * used in emergencies for management of acute heart failure

Question 30

What does RAAS contribute to?

Answer 30

The pathogenesis of heart failure

Question 31

What inhibitors are used to manage hypertension?

Answer 31

* benazepril * enalapril

Question 32

What are the most powerful diuretics?

Answer 32

* Loop diuretics * inhibit the H+/ K+ co-transporter

Question 33

What is furosemide commonly used for?

Answer 33

Treat almost all cases of congestive heart failure

Question 34

What is torasemide?

Answer 34

* Loop diuretic * longer duration of acting * (good for angry cats)

Question 35

What is spironolactone?

Answer 35

* act as specific antagonists of aldosterone * exert their effects by binding competitively to the mineralcorticoid receptor located in the kidneys, heart and blood vessels

Question 36

What is a thiazide diuretic?

Answer 36

* less powerful than loop diuretics * used as second or third line diuretics in end stage heart failure * disproportionate chloride loss that can result in acid-base disturbances and hypokalaemia

Question 37

What is the function of amlodipine?

Answer 37

* Blocks calcium channels in vascular smooth muscle * gradual onset and slow waning effect because of its slow binding and dissociation from the channel * little reflex tachycardia occurs making it a safe drug to use for hypertension