Cardiac Arrythmias

Question 1

5 Causes of Arrhythmias

Answer 1

1-Abnormal rhythmicity of the pacemake
2-Shift of pacemaker activity
3-Conduction of blocks
4-Abnormal pathways of impulse transmission
5-Spontaneous generation of abnormal impulses

Question 2

3 Normal Cardiac Rhythmns

Answer 2

1-Normal sinus rhythm: impulses originate at SA node at normal rate

2-Sinus arrhythmia: impulses originate at SA node at varying rates

3-Wandering atrial pacemaker: impulses originate from varying points in atria

In ALL: PQRST waves are normal. Spacing may just vary.

Question 3

Primary cause of sinus arrythmia

Answer 3

Breathing

Question 4

Normal HR for cats and dogs

Answer 4

Cats=140-220

Dogs=70-160

Question 5

Abnormally fast or slow heart rate originating at SA node

Answer 5

Fast-sinus tachycardia (maybe due to fever or hyperthroidism or in shock)
Slow-Sinus bradycardia

Question 6

Sinus Arrest

Answer 6

When SA node stops firing

Question 7

Describe ECG for sinus arrest

Answer 7

Normal PQRST waves then there’s nothing for ~5 seconds because SA node didn’t fire.

Question 8

First-degree atrioventricular block

Answer 8

There’s a fixed by prolonged PR interval. P-R interval is greater than 0.14 seconds n dog.

No dropped beats

Question 9

Second degree AV block: Mobitz type I

Answer 9

There’s progressive lengthening of PR interval with intermittent dropped beats.

Dropped beat.

Question 10

Second degree AV block: Mobitz type II

Answer 10

AV block at bundle of His lvl

There’s a sudden dropped QRS without prior PR lengthening.

Often see P:QRS in ratios

Question 11

Third degree AV block

Answer 11

Impulses originate at SA node but there’s no coordination with perkinje fibers.

Atria and ventricles are on different pages

P:QRS does not have a relationship.

Depending on if L or R perkinje fibers pick up impulse will give S or R wave.

L=S
R=R

Question 12

Supraventricular and Ventriculr Abnormalities (3)

Answer 12

Premature contraction
tachycardia
Fibrillation

Question 13

Reasons for premature contractions

Answer 13

• Contractions occur before they are supposed to
• Pulse deficit:ventricles don’t fill with blood properly and stroke volume is decreased
• Bigeminal pulse: every other beat may be premature

Question 14

Tachycardia definition

Answer 14

At least 3 or more premature contractions

Paroxysmal:lasts for varying amount off time and can stop whenever

Question 15

What are fibrillations

Answer 15

Many separate and small waves spreading at the same time in different directions over cardiac muscle.

Question 16

Difference between sinus tachycardia and supraventricular tachycardia

Answer 16

Sinus tach=physiological. SA node just firing faster

SupVen Tach= pathological: premature contractions

Question 17

Supraventricular premature contraction (3)

Answer 17

• Premature beats
• Looks similar to sinus beats
• Duration of QRS complexes are usually normal

Question 18

Atrial/Supraventricular paroxysmal tachycardia

Answer 18

There’s sudden burst (of at least 3) QRS complexes. Ventricles may not be properly filling with blood. HR is really high

Question 19

Atrial flutter

Answer 19

Impulses travel in circular course in atria setting up regular rapid flutter waves without QRS.

Irregular ventricular rate.

Question 20

Atrial fibrillation

Answer 20

Impulses take chaotic/random pathway to atria

No distinct P waves and no coordinated atrial contraction

QRS looks normal but irregular spaced

Question 21

Ventricular premature contraction

Answer 21

QRS are wide and bizarre due to ectopic focus in ventricular myocardium

Question 22

Ventricular bigeminy

Answer 22

Every other QRS wave is wide and bizarre.

May be due to stretched tissue in heart in ventricles

Question 23

Ventricular paroxysmal tachycardia

Answer 23

Random run of at least 3 QRS that are wide and bizzare.

Question 24

Ventricular fibrillation

Answer 24

No coordination in ventricular depolarization. No really defined QRS wave.

Question 25

Point of electroshock defib of the ventricles

Answer 25

To reset the heart. Shocking the heart will through everything into refractory and hopefully give the heat a chance for SA node to regain control and after repolarization of cells, will begin firing.