Anti-rhythmic Drugs Flashcards

1
Q

What is a common problem associated with digitalis pharmacologic treatment?

A

Cardiac arrhythmias

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2
Q

Should you treat asymptomatic or minimally symptomatic arrhythmias?

A

In general, treatment should be avoided

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3
Q

What is depolarization?

A

When the cells of the heart are activated

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4
Q

What is repolarization?

A

When the cells of the heart are at rest

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5
Q

What is occuring at the P-wave?

A

Atrial depolarization

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6
Q

What is occuring at the QRS complex?

A

Ventricular contraction

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7
Q

What is occurring at the T-wave?

A

Ventricular repolarization

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8
Q

What is occurring during the ventricular filling phase?

A

Cardiac muscles are completely repolarized

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9
Q

What is the mechanisms of arrhythmias?

A

Disturbances in impulse formation and conduction

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10
Q

What regulates the pacemaking activity?

A

Sympathetic and parasympathetic activity

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11
Q

What are the pacemaking cells in the heart?

A

Purkinje cells

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12
Q

What phase does disturbed early afterdepolarization (EADs) occur?

A

Phase 3

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13
Q

What phase does disturbed delayed afterdepolarization (DADs) occur?

A

Phase 4

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14
Q

EADs are usually triggered by factors that prolong action potential duration in the ventricle which leads to QT prolongation which leads to what adverse effects?

A

Torsades de pointes (specific V Tach), tachycardia, and other arrhythmias

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15
Q

QT prolongation is caused by a

A

Blockage of rapidly activating delayed rectifier potassium channels

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16
Q

What is an example of an intrinsic cause of QT prolongation?

A

Congenital long QT syndrome

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17
Q

What are examples of extrinsic causes of QT prolongation?

A

Medications (SSRI’s, SNRI’s and others)

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18
Q

DADs can occur when there is an excess of what?

A

Excess accumulation of intracellular calcium

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19
Q

What are some triggers of DADs?

A

Digitalis toxicity, excess catecholamines, myocardial ischemia

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20
Q

In complete heart block what cells can dictate ventricular rate?

A

Latent Purkinje Cells

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21
Q

What is Wolff-Parkinson-White Syndrome?

A

re-entry circuit of atrial tissue, AV node, ventricular tissue, accessory AV connection (blockage of SA node)

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22
Q

What is the classic pattern seen on EKG in atrial flutter?

A

Sawtooth Pattern

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23
Q

What are the types of arrhythmias?

A

Atrial Fibrillation
Atrial Flutter
AV Nodal Re-Entry (SVT)
Ventricular Fibrillation
Ventricular Tachycardia

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24
Q

What are Class 1 anti-arrhythmic agents action?

A

Sodium channel blockade; these drugs have effects on the action potential duration

Reduce phase 0 slope and peak of action potential

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25
Q

What are the Class 2 anti-arrhythmic agents action?

A

Sympatholytic, drugs with this action reduce B-adrenergic activity in the heart (SA Node activity)

i.e. Beta Blockers (decrease heart rate and contractility)

26
Q

What are the Class 3 anti-arrhythmic agents action?

A

Action manifests as prolongation of the action potential duration. Block rectifier potassium current.

Delay repolarization (Phase 3)- increase ADP and ERP

27
Q

What are the Class 4 anti-arrhythmic agents action?

A

Blockade of the cardiac calcium current. Slows conduction in regions where the action potential upstroke is calcium dependent (SA and AV node)

28
Q

What is the absolute refractory period (ARP)?

A

Time during which another stimulus will not lead to another AP

29
Q

What is the relative refractory period (RRP)?

A

Interval following ARP in which a 2nd stimulus is inhibited, but not impossible

30
Q

What is the effective refractory period (ERP)?

A

Time in which a cell does not produce a new AP (phase 0, 1, 2, 3)

31
Q

What drug can be used to treat AV block?

A

Atropine

32
Q

What drug class can treat sinus tachycardia?

A

Class II, IV

33
Q

What drug class can treat atrial fibrillation/flutter?

A

Class IA, IC, II, III, IV, digitalis

34
Q

What drug class can treat SVT?

A

Class IA, IC, II, III, IV, adenosine

35
Q

What drug class can treat ventricular tachycardia?

A

Class I, II, III

36
Q

What drug class can treat premature ventricular complexes?

A

Class II, IV, magnesium sulfate

37
Q

What can treat digitalis toxicity?

A

Class IB, magnesium sulfate

38
Q

What drugs can not be used concomitantly with Class IA agents due to precipitating ventricular fibrillation?

A

Class I and Class III

39
Q

What are the Class IA agents?

A

Procainamide
Quinidine

40
Q

What feature defines the clinical use of class IB agents?

A

Have greater effects on cells with long action potentials (Purkinje, ventricullar cells) compared to arterial cells

41
Q

What are the Class IB agents?

A

Lidocaine
Mexiletine

42
Q

Of the Class IB agents, which drug has a narrow therapeutic index?

A

Mexiletine

43
Q

What are the Class IC agents?

A

Flecainide
Propafenone

44
Q

For patients with heart failure with low EF (<35%) and/or hypertension what would be considered first line treatment in treating atrial fibrillation?

A

Amiodarone

45
Q

For patients with CAD what would be considered first line treatment in treating atrial fibrillation?

A

Sotalol

46
Q

What are the indications for Digoxin?

A

Primary indication is heart failure, also used to treat supraventricular tachydysrthythmias

47
Q

What are the indications for Adenosine?

A

Drug of choice for terminating paroxysmal SVT
Wolf-Parkinson-White Syndrome

48
Q

What are the indications for Atropine?

A

Aborts life-threatening bradycardias, second degree and complete heart block

49
Q

What are the indications for Quinidine and what is its drug class?

A

Class 1A Drug

Broad-spectrum agent active against supraventricular and ventricular dysrhythmias

50
Q

What class does Procainamide belong and what are it’s primary indications?

A

Class 1A

Acute arterial or ventricular arrythmias but toxicity makes it less desirable for long term use

Can be used in Wolf-Parkinson-White

51
Q

What class does Disopyramide belong and what is its primary indication?

A

Class 1A

Ventricular Dyshythmias

52
Q

What class does Lidocaine belong and what is its primary indication?

A

Class 1B

Used only for short-term treatment of ventricular dyshythmias

53
Q

What is an oral analogue of lidocaine used for chronic treatment of ventricular dysrhythmias?

A

Mexiletine (Class 1B)

54
Q

What is the primary indication for Class 1C drugs?

A

Maintenance therapy of supraventricular dysrhythmias

Flecainide
Propafenone

55
Q

What beta-blocker is most widely used to treat cardiac arrhythmias?

A

Metoprolol

56
Q

What is the indication for Esmolol?

A

Immediate treatment of ventricular rate in patients with supraventricular arrhythmias only

57
Q

What are the indications for Sotalol and what are the two drug classes in which it falls?

A

Life threatening ventricular arrhythmias or for cardioversion and maintenance of NSr with patients in aFib

Class II and III

58
Q

What are the indications for Amiodarone?

A

Highly effective against both arterial and ventricular dysrythmias

Approved only for life-threatening ventricular dysrhythmia that have been refractory tosafer agents

59
Q

What are the major side effects of Amiodarone?

A

Pulmonary fibrosis, thyroid toxicity, visual impairment, photosensitivity, hepatotoxicity, and hepatotoxicity

60
Q

What class III medication has the longest half-life?

A

Amioradone (20-100 days)