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Pharm Exam > Antiarrhythmics deck > Flashcards

Antiarrhythmics deck Flashcards

1
Q

What are the normal steps in heart electrical activity? (4)

A
  1. SA node discharge
  2. Spread through atria
  3. AV node discharge
  4. Propagation through Purkinje fibres
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2
Q

The process of cardiac muscle contraction is called ________.

A

It is called excitation-contraction coupling

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3
Q

Membrane potential is maintained by __ , __ & __ on either side of the cell membrane.

A

Sodium (Na+)

Calcium (Ca2+)

Potassium (K+)

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4
Q

At rest, intracellular __ is low.

This is maintained by ______.

A

At rest, intracellular sodium (Na+) is low

This is maintained by Na+/K+ ATPase

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5
Q

What are the 3 action potential phases?

A

Rapid depolarization

Plateau phase

Repolarization

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6
Q

What is the rapid depolarization phase of the action potential phases

A

Na+ influx through rapidly opening Na+ channels

Sodium enters the cell rapidly

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7
Q

What happens in the plateau phase of the action potential phases?

A

Ca+2 influx through slowly opening Ca2+ channels

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8
Q

What is the first step of the excitation-contraction coupling?

A

Action potential leads to increased calcium levels

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9
Q

What is the second step of the excitation-contraction coupling?

A

The Calcium binds to troponin C and uncovers myosin binding site for actin

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10
Q

What is the third step of the excitation-contraction coupling?

A

The actin and myosin cross-linkages form, triggering the contraction

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11
Q

What is a normal heart rate?

A

60-80 bpm

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12
Q

What are arrhythmias?

A

Arrhythmias are abnormal heart rhythms due to electrical issues

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13
Q

What is bradycardia?

A

Slow heart rate <60 bpm

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14
Q

What is tachycardia?

A

Fast heart rate > 100bpm

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15
Q

What is automaticity?

A

The ability of some cardiac cells, mainly the SA node, to generate their own impulses

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16
Q

What is the order of the electrical signal through the heart?

A

SA node fires -> spreads through atria causing coordinated contraction

Next AV node -> his bundle -> Purkinje fibers -> coordinated contraction

17
Q

What is a reentrant in arrhythmia?

A

When a signal reenters or circulates through tissue instead of following its normal path

can lead to abnormal rhythms

18
Q

What are atrial flutters?

A

arrhythmia of 200-350bpm

19
Q

what are atrial fibrillations?

A

300-500 bpm arrhythmia

20
Q

Are atrial flutters/fibrillations dangerous?

A

They don’t always impact cardiac output but can become serious. Treated if symptoms develop or patient is at risk

21
Q

Ventricular tachycardia is…

A

when the lower chambers of the heart beat too fast

22
Q

Is Ventricular tachycardia dangerous?

A

It can occur occasionally and be fine but if its consistent it requires quick treatment

23
Q

What is ventricular fibrillation?

A

When the lower chambers begin to beat rapidly AND irregularly

24
Q

Is ventricular fibrillation dangerous?

A

It’s incredibly fatal.

25
Q

How do we treat VTac and VFib?

A

Defibrillators stop all heart electrical activity in an attempt to allow a normal rhythm to resume

26
Q

What are antiarrhythmics?

A

Drugs that aim to fix abnormal cardiac rhythm

27
Q

How do antiarrhythmic agents work?

A

All antiarrhythmic drugs alter ion flow across the membrane.

Antiarrhythmics have a narrow therapeutic index and can CAUSE arrhythmias

28
Q

When is it worth it to treat with an antiarrhythmic?

A

When CO is reduced or when a more serious arrhythmia might develop

29
Q

What are Class I: Na+ blockers?

A

IA - Quinidine

IB- Lidocaine

30
Q

What are class II beta blockers?

A

Propranolol, Metoprolol

31
Q

What are class III prolonged action potential/K+ channel blockers?

A

Amiodarone

32
Q

What are Class IV Calcium channel blockers?

A

Verapamil

33
Q

What do sodium channel blockers do?

A

Reduce sodium recovery, decreases conduction and excitation

34
Q

What do potassium blockers do?

A

Prolong the action potential which increases the refractory period

35
Q

Why is quinidine used less that lidocaine as an antiarrhythmic?

A

Quinidine is an IA antiarrhythmic with lots of side effects

Lidocaine is an IB antiarrhythmic that is used much more frequently (through IV)

36
Q

How do class II: beta-blockers work as antiarrhythmics?

A

Propranolol and metoprolol inhibit SNS effects, slowing HR

37
Q

How do class III potassium channel blockers work as anti-arrhythmics?

A

Amiodarone is a potassium blocker, it prolongs the action potential, also affects beta receptors and Na and Ca channels

38
Q

How do class IV: Calcium channel blockers work?

A

Verapamil is a calcium channel blocker

It reduces cardiac contractility and vasodilation.

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