Cardiac Arrhythmia

Question 1

What does PR interval indicate?

Answer 1

Measures Conduction time from atrium to ventricle

Question 2

What does QRS wave represent

Answer 2

The time it takes for all ventricular cells to be excited..
I.e intraventricular conduction time

Question 3

The electrical activities of the heart control…….. of the heart

Answer 3

Rhythm

Question 4

The mechanical activities control the …….. of the heart

Answer 4

Pumping action of the heart

Question 5

When the mechanical and electrical part of the heart fails respectively it is called

Answer 5

Heart failure
Arrhythmia

Question 6

What is the pathophysiology of Arrhythmia?

Answer 6

There’s a change in the membrane potential of cardiac cells which affect the rhythm…

Anti Arrhythmia drugs functions by Modulating the actions of ion channels on the membrane

Question 7

What forms the electrical conducting system of the heart

Answer 7

The pacemaker cells

Question 8

The pacemaker cells include

Answer 8

Bundle of His
Purkinje fibre
SA node
AV node

Question 9

What is the native pacemaker of the cell

Answer 9

SA node is the intrinsic pacemaker of the cell.

It has the highest intrinsic firing rate 60-100times/min

Question 10

The intrinsic firing activity of the other pacemaker cells are

Answer 10

AV node and bundle of His 50-60/min

Purkinje fibre 30-40/min

Question 11

The other pacemakers overriden by SA node is called

Answer 11

Latent pacemaker

Question 12

Explain override suppression

Answer 12

This occurs when the SA node suppresses the intrinsic firing activity of the pacemaker cells and entrains them to fire at the SA nodal firing activity

Question 13

The two major mechanism in the pathophysiology of cardiac Arrhythmia

Answer 13

Change in automaticity
Changes in conductivity

Question 14

What does the PR interval represent

Answer 14

The time it takes for conduction to spread from the the atrium to the ventricles

Question 15

What does the QRS complex represent

Answer 15

Intraventricular depolarization.

Question 16

What is the QT interval

Answer 16

The time it takes for ventricular action potential

Question 17

ST segment represents

Answer 17

Plateau phase

Question 18

The intrinsic rate of firing of the SA node is

Answer 18

60-100 beats per minute

Question 19

The intrinsic firing activity of the AV node and bundle of His is ……

Answer 19

50-60 beats per min

Question 20

The intrinsic firing activity of the Purkinje fibre is

Answer 20

30-40 beats per min

Question 21

What is the nernst potential?

Answer 21

The difference between an ions nernst potential and the cell membranes potential

Question 22

What results in early after-depolarization

Answer 22

This occurs when there is incomplete inactivation of Na + channel or decrease repolarizing potential of k+

Question 23

Example of early after depolarization is seem in…… and it results in ………

Answer 23

Congenital QT syndrome results in torsades de pointes

Question 24

What results in delayed after-depolarization

Answer 24

When Na+/K+ is shallow
Ca+ conc is high
B adrenergic stimulation
Digitalis glycoside toxicity

Question 25

Delayed after-depolarization results in tachycardia and extra stole if it results in ………….

Answer 25

Another DAD