ECG

Question 1

What leads look at the inferior surface of the heart?

Specifically in the heart, where do they see?

Answer 1

Lead III, aVF, II

SAN + AVN

Question 2

What leads look at the anterior surface of the heart?

Specifically in the heart, where do they see?

Answer 2

V1, V2, V3, V4

LV, Septum, RV

Question 3

What leads look at the lateral surface of the heart?

Specifically in the heart, where do they see?

Answer 3

Lead I, avL, V5, V6

Lateral ventricles

Question 4

If you have a short PR interval (<0.12s) what does this suggest?

0.12s - 3 small boxes

Answer 4

It suggests that there is an accessory pathway between the atria and the ventricles (like in Wolff-Parkinson-White syndrome)

Question 5

If you have a prolonged PR interval (>0.20s) what does this suggest?

0.20s - 5 small boxes

Answer 5

It suggests that there is heart block

Question 6

How long is the QRS complex meant to last?

Answer 6

0.12s - 3 small boxes

Question 7

How to calculate the rate (bpm) of an irregular ECG

Answer 7

No. of QRS complexes in 6seconds x 10

Question 8

How many big boxes make 1 second?

Answer 8

5

Question 9

Atrial fibrillation is caused by multiple atrial foci firing off impulses in a chaotic fashion.

Describe the waves seen in AF

Answer 9

Normal/narrow QRS

Missing P wave

Irregular R-R intervals

Question 10

Describe an ECG of a Complete heart block

Answer 10

No relationship between P waves and QRS complexes

Question 11

Give 3 causes of heart block?

Answer 11

1. Acute MI of right coronary artery
2. Degeneration of electrical conduction system
3. Atrial myxodema

Question 12

Describe an

A) Acute Non-STEMI/Severe ischaemia (unstable angina) ECG
B) Old Non-STEMI/Severe ischaemia (unstable angina) ECG

Answer 12

A) ST segment depression and/or T wave inversion

B) (weeks later) No Q waves, ST segment depression + T wave inversion are no longer present

Question 13

Describe an

A) Acute STEMI ECG
B) Old STEMI ECG

When do the wave malformations return to normal

Answer 13

A) ST segment elevation (returns to normal days later)

B) Deep Q waves (this will persist, even weeks later), T wave inversion (returns to normal weeks later)

Question 14

What happens to the ST segment of a stable angina patient whilst they are exercising?

Answer 14

ST segment depression

Question 15

ST depression is caused by poor myocardial perfusion (NOT sudden coronary occlusion)

But when can an ST depression be caused by a sudden occlusion of an artery?

What leads would this pathology be seen in?

What areas of the heart would be effected?

Answer 15

In a posterior STEMI, sudden occlusion of left circumflex artery.

Seen in leads V3 and V4 so apex and anterior heart lost its perfusion

Question 16

What causes ST elevation?

Answer 16

Sudden and complete occlusion of the coronary artery

Question 17

What is seen on an ECG of a patient with pericarditis?

Answer 17

Widespread saddle shape ST elevation

PR segment depression

Question 18

What is seen on an ECG of a patient that is in cardiac arrest (ventricular fibrillation)

Answer 18

Pulseless electrical activity

Question 19

What does pulseless electrical activity mean?

Answer 19

A heart rhythm is seen on the ECG but there is no pulse (generated by this heart rhythm)

Question 20

What are 3 signs that could be seen in an ECG of Trifascicular block?

Answer 20

1. Prolonged PR interval (first degree AV block)
2. Wide S wave on lateral leads (I, avL, V5 and V6)
3. Tall and wide QRS waves on anterior leads (V1, V2, V3 and V4)