Arrhythmias

Question 1

What is the name of a normal heart rhythm?

Answer 1

Sinus rhythm

Question 2

Arrhythmias can be supraventricular, junctional or ventricular. What do these terms mean?

Answer 2

Supraventricular - generated in atria
Junctional - generated in AVN
Ventricular - generated in ventricles

Question 3

What are different regularities of arrhythmias?

Answer 3

Regular
Regularly irregular
Irregularly irregular

Question 4

What are premature complexes?

Answer 4

Premature beats

Generated when the heart shouldn’t be depolarising

Question 5

What may premature complexes be associated with?

Answer 5

Pulse deficits (audible beat may not generate palpable pulse)

Question 6

Runs of premature complexes are referred to as what? What is needed to see the origin of the arrhythmia?

Answer 6

Supraventricular or ventricular tachycardia

ECG to see if supra ventricular, junctional or ventricular

Question 7

Supraventricular premature complex (sVPC) and junctional premature complex have what changes to their ECG?

Answer 7

Normal QRS wave as following correct AP pathway, but wrong place on graph
No P wave as atria not properly depolarising

Question 8

Ventricular premature complexes (VPCs) have what changes to their ECG?

Answer 8

Bizarre! Not following correct AP pathway
Wider QRS - not following His-Purkinje system so AP takes longer
No P wave as atria not involved in AP
T wave in opposite direction to QRS

Question 9

What is atrial fibrillation? Why does this happen?

Answer 9

Fast, irregular beating of the atria
Atrial myocardium generate random APs all across the atria
AVN cannot keep up

Question 10

What does atrial fibrillation cause?

Answer 10

Decreased CO

Major cause of stroke

Question 11

What is atrial fibrillation associated with?

Answer 11

Large atria (normal horse hearts) and atrial stretch

Question 12

What does atrial fibrillation look like on an ECG?

Answer 12

Supraventricular tachycardia- no P waves, irregular R-R interval, jagged baseline (horses only)

Question 13

What is AV block?

Answer 13

Conduction of AP is slowed or blocked by the AVN
Cardiac cause (as opposed to metabolic cause) of bradycardia

Question 14

How many types of AV block are there?

Answer 14

1st degree
2nd degree (separated into Mobitz I and II)
3rd degree

Question 15

What does 1st degree AV block show on an ECG?

Answer 15

Prolonged P-R interval

Shows slowing of conduction

Question 16

What does 2nd degree AV block involve?

Answer 16

AVN partially blocked

Sometimes P wave fails to generate QRS, may be fixed ratio of P:QRS.

Question 17

What is Mobitz I also called? What does it show on an ECG?

Answer 17

Wenckebach phenomenon

Progressive lengthening of P-R interval until no QRS

Question 18

What does Mobitz II show on an ECG?

Answer 18

P waves conducted at constant rate (no progressive lengthening)
Intermittently there are one or more non-conducted beats

Question 19

What does 3rd degree AV block involve? What takes over as the hearts pacemaker?

Answer 19

P and QRST complexes present but unrelated

AVN takes over from SAN, but often requires electronic pacemaker

Question 20

What is sick sinus syndrome?

Answer 20

Arrhythmia due to sick SAN