Antiarrhythmics deck

Question 1

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

Answer 1

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

Question 2

The process of cardiac muscle contraction is called ________.

Answer 2

It is called excitation-contraction coupling

Question 3

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

Answer 3

Sodium (Na+)

Calcium (Ca2+)

Potassium (K+)

Question 4

At rest, intracellular __ is low.

This is maintained by ______.

Answer 4

At rest, intracellular sodium (Na+) is low

This is maintained by Na+/K+ ATPase

Question 5

What are the 3 action potential phases?

Answer 5

Rapid depolarization

Plateau phase

Repolarization

Question 6

What is the rapid depolarization phase of the action potential phases

Answer 6

Na+ influx through rapidly opening Na+ channels

Sodium enters the cell rapidly

Question 7

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

Answer 7

Ca+2 influx through slowly opening Ca2+ channels

Question 8

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

Answer 8

Action potential leads to increased calcium levels

Question 9

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

Answer 9

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

Question 10

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

Answer 10

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

Question 11

What is a normal heart rate?

Answer 11

60-80 bpm

Question 12

What are arrhythmias?

Answer 12

Arrhythmias are abnormal heart rhythms due to electrical issues

Question 13

What is bradycardia?

Answer 13

Slow heart rate <60 bpm

Question 14

What is tachycardia?

Answer 14

Fast heart rate > 100bpm

Question 15

What is automaticity?

Answer 15

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

Question 16

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

Answer 16

SA node fires -> spreads through atria causing coordinated contraction

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

Question 17

What is a reentrant in arrhythmia?

Answer 17

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

can lead to abnormal rhythms

Question 18

What are atrial flutters?

Answer 18

arrhythmia of 200-350bpm

Question 19

what are atrial fibrillations?

Answer 19

300-500 bpm arrhythmia

Question 20

Are atrial flutters/fibrillations dangerous?

Answer 20

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

Question 21

Ventricular tachycardia is…

Answer 21

when the lower chambers of the heart beat too fast

Question 22

Is Ventricular tachycardia dangerous?

Answer 22

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

Question 23

What is ventricular fibrillation?

Answer 23

When the lower chambers begin to beat rapidly AND irregularly

Question 24

Is ventricular fibrillation dangerous?

Answer 24

It’s incredibly fatal.

Question 25

How do we treat VTac and VFib?

Answer 25

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

Question 26

What are antiarrhythmics?

Answer 26

Drugs that aim to fix abnormal cardiac rhythm

Question 27

How do antiarrhythmic agents work?

Answer 27

All antiarrhythmic drugs alter ion flow across the membrane. Antiarrhythmics have a narrow therapeutic index and can CAUSE arrhythmias

Question 28

When is it worth it to treat with an antiarrhythmic?

Answer 28

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

Question 29

What are Class I: Na+ blockers?

Answer 29

IA - Quinidine IB- Lidocaine

Question 30

What are class II beta blockers?

Answer 30

Propranolol, Metoprolol

Question 31

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

Answer 31

Amiodarone

Question 32

What are Class IV Calcium channel blockers?

Answer 32

Verapamil

Question 33

What do sodium channel blockers do?

Answer 33

Reduce sodium recovery, decreases conduction and excitation

Question 34

What do potassium blockers do?

Answer 34

Prolong the action potential which increases the refractory period

Question 35

Why is quinidine used less that lidocaine as an antiarrhythmic?

Answer 35

Quinidine is an IA antiarrhythmic with lots of side effects Lidocaine is an IB antiarrhythmic that is used much more frequently (through IV)

Question 36

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

Answer 36

Propranolol and metoprolol inhibit SNS effects, slowing HR

Question 37

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

Answer 37

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

Question 38

How do class IV: Calcium channel blockers work?

Answer 38

Verapamil is a calcium channel blocker It reduces cardiac contractility and vasodilation.