ECG

Question 1

What is an ECG?

Answer 1

A representation of the electrical events of the cardiac cycle.

Question 2

What does P wave represent?

Answer 2

Atrial Depolarisation (atrial contraction)

Question 3

What does PR interval represent?

Answer 3

Delay at the AV node.

Time taken for impulse to travel from atria, through AV node, to the ventricles

Question 4

What does QRS complex represent?

Answer 4

Ventricular depolarisation (Ventricular contraction)

Question 5

What does T wave represent?

Answer 5

Ventricular repolarization

Question 6

What does QT interval represent?

Answer 6

Entire duration of ventricular electrical activity.

Question 7

How to calculate Heart Rate?

Answer 7

Standard Method: Count number of R waves in a 6-second strip and multiply this number by 10

300 Rule: (for regular rhythms), divide 300 by number of large squares between R waves

Question 8

How to know whether rhythm regular/irregular?

Answer 8

Regular rhythm: R-R intervals are consistent

Irregular rhythm: R-R intervals vary

Question 9

True/False

If P waves are present, regular, and found before each QRS complex, this means it is a normal sinus rhythm.

Answer 9

True

Question 10

What does prolonged PR interval mean?

Answer 10

1st degree heart block. (AV block)

Question 11

Suggest ECG finding for:

Irregular rhythm with no distinct P waves

Answer 11

Atrial Fibrillation

Question 12

Suggest ECG finding for:

Sawtooth pattern of P waves

Answer 12

Atrial flutter

Question 13

Suggest ECG finding for:

Wide QRS complexes with a regular rapid rhythm (more than 100 beats/min)

Answer 13

Ventricular Tachycardia

Question 14

Suggest ECG finding for:

No P wave, no QRS complex, no T wave seen.

Rate, rhythm cannot be determined, irregularly irregular rhythm

Answer 14

Ventricular fibrillation

Question 15

Suggest the type of AV block in this pattern:

Regular rhythm
Uniformly prolonged PR interval

Answer 15

1st degree AV block

Question 16

Suggest the type of AV block in this pattern:

Irregular rhythm
Progressive PR interval prolongation until QRS missing

Answer 16

2nd degree AV block, Mobitz Type I

Question 17

What does T wave inversion indicate?

Answer 17

Ischaemia

Question 18

What is seen in ECG for a patient with Left Ventricular Hypertrophy (LVH)?

Answer 18

Tall R waves in lead V5/V6

Deep S waves in lead V1/V2

Question 19

Describe ECG finding in 2nd degree AV block, Mobitz Type II.

Answer 19

Irregular rhythm.
PR interval may be normal or prolonged, BUT is Constant! and fixed!

Unexpected blocked P waves, don’t know when QRS drops

Question 20

Describe ECG for a 3rd degree AV block.

Answer 20

P wave and QRS complex march out separately (no pattern/relationship).

Some QRS bizarre.

PR interval constantly changing.