7 ECG Abnormalities

Question 1

List sites a abnormal supra-ventricular rhythms may arise

Answer 1

• Sinus node
• Atrium
• AV node

Question 2

How are supra-ventricular rhythms conducted into the ventricles?

Answer 2

His-Purkinje system

Question 3

What are QRS complexes like in supra-ventricular rhythms?

Answer 3

Narrow

Question 4

In ventricular rhythms what are the QRS complexes like?

Answer 4

Larger than 3 small boxes

Question 5

What is sinus bradycardia and tachycardia?

Answer 5

B = below 60
T = Above 100

Question 6

What is the most common cardiac arrhythmia?

Answer 6

Atrial fibrillation

Question 7

In AF where are electrical impulses initiated from?

Answer 7

Different sites in the atrium called ectopic sites

Question 8

How does AF present on an ECG?

Answer 8

• Absent P waves
• Wavy baseline
• Narrow QRS complex
• Irregularly irregular

Question 9

What are the most common complications of atrial fibrillation?

Answer 9

Blood clots arising in the atria

Question 10

What is heart block?

Answer 10

Block in the electrical conducting system between the atria and the ventricles

Question 11

What are common causes of heart block?

Answer 11

Acute myocardial infacrtion

Question 12

What is 1st degree AV heart block?

Answer 12

Prolonged PR interval, but every P wave is still followed by a QRS complex
PR interval is bigger than 1 PR square

Question 13

What is 2nd degree AV heart block?

Answer 13

Atria are contracting normally but not every impulse from the atria is making it through to the ventricles

Question 14

What is Mobitz type 1?

Answer 14

progressive PR lengthening until one P wave is not conducted

Question 15

What is Mobitz type 2?

Answer 15

The PR interval is normal, but then get a sudden non conduction of a beat

Question 16

What is 3rd degree heart block?

Answer 16

Atria are doing there thing but impulse is not getting through, no relationship between the p wave and the QRS complexes

Question 17

What is a ventricular ectopic beat?

Answer 17

Causes ventricular contraction before the underlying rhythm would normally depolarise the ventricles
Get a wider and different shaped QRS complex compared to the usual

Question 18

What is ventricular tachycardia?

Answer 18

Get a consecutive run of more than 3 ectopic beats

Question 19

In terms of cardiac output describe atrial fibrillation and ventricular fibrillation?

Answer 19

Cardiac output present in AF, no cardiac output or heart beat is present in VF

Question 20

Which part of the heart is most vulnerable to ischemia?

Answer 20

Sub endocardial muscle

Question 21

How is ischaemia identified on a ECG?

Answer 21

ST segment depression or T wave inversion

Question 22

How is myocardial infarction identified on an ECG?

Answer 22

ST elevation

Question 23

What is a pathological q wave a sign of?

Answer 23

A previous myocardial infraction

Question 24

Describe a pathological Q wave?

Answer 24

More than 1 small square wide or 2 small square deep, the depth is more than 1/4 of the height of subsequent R wave and is greater than 1/3 the amplitude of the QRS complex

Question 25

How can identify hyperkalameia on a ECG?

Answer 25

Tall T wave

Question 26

How can identify hypokalaemia?

Answer 26

Low T wave

Question 27

What is the cardiac axis?

Answer 27

The average (overall) direction of spread of the ventricular
depolarisation

Question 28

What is left axis deviation?

Answer 28

When overall direction ventricular depolarisation is upwards and to the left

Question 29

What is right axis deviation?

Answer 29

When overall direction ventricular depolarisation is downwards and to the right

Question 30

What is often the earliest ECG change seen during myocardial infarction?

Answer 30

Tall peaked T waves

Question 31

How do you tell if the cardiac axis is normal?

Answer 31

In normal cardiac axis Lead II has the most positive deflection compared to Leads I and III

Question 32

What does a prolonged PR interval suggest?

Answer 32

An atriventricular delay