CVS 9 (Drugs & the CVS) Flashcards Preview

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Flashcards in CVS 9 (Drugs & the CVS) Deck (22)
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1
Q

What are the 3 usual causes of arrhythmia’s?

A

1) Ectopic pacemaker activity
2) After depolarisations
3) Re-entry loops

2
Q

Name some types of arrhythmia’s:

A
  • Bradycardia
  • Atrial flutter
  • Fibrillation
  • Ventricular tachycardia
  • Supraventricular tachycardia
3
Q

Name the 4 classes of anti-arrhythmic drugs:

A

1) Drugs that block voltage-gated Na+ channels
2) beta-adrenoceptor antagonists
3) Drugs that block K+ channels
4) Drugs that block Ca2+ channels

4
Q

Give an example of a class I anti-arrhythmic drug, and its action:

A

Lidocaine - blocks voltage-gated Na+ channels

5
Q

What type of anti-arrhythmic drug is Lidocaine?

A

Class I - Drug that blocks voltage-gated Na+ channels

6
Q

Give an example of a class II anti-arrhythmic drug, and its action:

A

Propanolol/Atenolol

Beta-adrenoceptor antagonist = decreases slope of pacemaker potential

7
Q

What type of anti-arrhythmic drug is Propanolol?

A

Class II - Beta-adrenoceptor antagonist

8
Q

Explain Wolff-Parkinson-White syndrome:

A

Re-entry loop due to an extra conduction pathway causes tachycardia

9
Q

What type of anti-arrhythmic drug is Amiodarone?

A

Class III - Drug that blocks K+ channels

10
Q

Name the drug which is used to treat tachycardia associated with Wolff-Parkinson-White syndrome:

A

Amiodarone

11
Q

Give an example of a class IV anti-arrhythmic drug, and its action:

A

Verapamil

  • Blocks Ca2+ channels
  • Decreases slope of AP
  • Decreases AV nodal conduction
  • Decreases force of contraction
12
Q

What type of anti-arrhythmic drug is Verapamil?

A

Class IV = Drug that blocks Ca2+ channels

13
Q

Which circulating molecule is anti-arrhythmic, by briefly blocking conductance, restoring the sinus rhythm?

A

Adenosine

14
Q

Define heart failure:

A

Chronic failure of the heart to provide sufficient output to meet the body’s requirements.

15
Q

Name the 2 types of drugs which can increase cardiac output during heart failure:

A

1) Cardiac glycosides

2) beta-1 adrenoceptor agonists

16
Q

Give an example of a cardiac glycoside, and explain how it can be used to treat heart failure:

A
Digoxin/Ouabain
- Inhibits Na+/K+-ATPase
- Reduced activity of NCX
- More Ca2+ stored in SR
= Increased force of contraction (^CO)
17
Q

Give an example of a beta-1 adrenoceptor agonist, and explain how it can be used to treat heart failure:

A

Dobutamine/Adrenaline/NA

  • Increases contractility = Increases cardiac output
  • Short-term = used in acute but reversible heart failure, after surgery
18
Q

Name 3 types of drugs which can decrease the workload of the heart during heart failure:

A

1) ACE inhibitors
2) Beta-adrenoceptor antagonists
3) Diuretics

19
Q

Explain how an ACE inhibitor can be used to treat heart failure:

A

Prevents formation of Angiotensin II:

  • less vasoconstriction = decreases blood pressure = decreased afterload
  • less Na+ and H2O reabsorption = less fluid retension = decreased preload
20
Q

Name the 2 types of drugs used to treat AF and/or valve disease:

A

1) Anticoagulants

2) Antiplatelets

21
Q

Give an example of an anticoagulant, and explain how it is used to treat AF + valve disease:

A

Heparin (short-term)

  • Activates anti-thrombin III = inactivates Thrombin + Factor Xa
  • Decreases risk of thrombus formation

Warfarin (long term)
- Inhibits vitamin K reductase
= no production of Factors II, VII, IX + X
- Decreases risk of thrombus formation

22
Q

Give an example of an antiplatelet drug, and explain how it is used to treat AF + valve disease:

A

Aspirin

  • Inhibits cyclo-oxygenase-1
  • Prevents formation of Thromboxane (an inducer of platelet aggregation)
  • Decreases risk of thrombus formation