Week 5 - ECG's

Question 1

What does the P Wave:
- Represent?
- Duration?
- Height?

Answer 1

Represents = Atrial Depolarisation
Duration = 2-5 small boxes
Height = 2.5 small boxes

Question 2

What does the PR interval:
- Represent?
- Duration?

Answer 2

Represents = Time for the impulse to travel across the atria through the AV node
Duration = 3-5 small boxes

Question 3

What does the QRS Complex:
- Represent?
- Duration?
- Amplitude?

Answer 3

Represents = Ventricular Depolarisation
Duration = < 3 boxes
Amplitude = 2-3 large boxes

Question 4

What does the ST segment:
- Starting position?
- Represent?
- Duration?

Answer 4

Starts at the end of the QRS complex
Represents = Start of Ventricular Repolarisation
Duration = 3 small boxes

Question 5

What does the T Wave:
- Represent?
- Duration?

Answer 5

Represents = Ventricular Repolarisation
Duration = 4 small boxes

Question 6

How do you interpret Heart Rate on ECG’s?

Answer 6

Count # of QRS complexes in a 30 seconds span and multiply by 2

Question 7

What is a normal sinus rhythm?

Answer 7

Rate of 60-100 beats/min
Regular + Same PQRS complexes

Question 8

What are the 3 Atrial Arrythmias?

Answer 8

• Premature Atrial Contraction (PAC)
• Atrial Flutter
• Atrial Fibrillation

Question 9

Describe the pathology behind Atrial Arrhythmias

Answer 9

• Results from problems in the SA node
• Abnormalities occur in the P wave

Question 10

What occurs on an ECG to identify Sinus Arrhythmias/Dysrhythmias?

Answer 10

Irregularity in spacing of PQRS complexes

Question 11

What occurs on an ECG to identify Premature Atrial Contraction (PAC)?

Answer 11

P wave occurs earlier than expected on ECG

Question 12

What occurs on an ECG to identify Atrial Flutter?

Answer 12

Rapid, regular atrial contraction

Appearance = recognised by saw toothed baseline with normal QRS complex

Question 13

What occurs on an ECG to identify Atrial Fibrillation?

Answer 13

Rapid, chaotic atrial arrhythmia

Appearance = no P waves, erratic baseline, normal QRS complexes ~80-150 beats/min

Question 14

What are the 4 Ventricular Arrythmias?

Answer 14

• Premature Ventricular Contraction / Ventricular Ectopic Beat (PVC/VEB)
• VT
• VF
• Asystole

Question 15

What occurs on an ECG to identify Premature Ventricular Contraction / Ventricular Ectopic Beat?

Answer 15

Ectopic, premature beat arising from somewhere in the ventricle

Appearance = wide (due to slow conduction), tall, bizarre ventricular complex with a compensatory pause following

Question 16

What occurs on an ECG to identify Ventricular Tachycardia (VT)?

Answer 16

Appearance = wide, tall, bizarre QRS complexes with no P wave

Question 17

What occurs on an ECG to identify Ventricular Fibrillation (VF)?

Answer 17

Chaotic activity of the ventricle originating when multiple foci fire and coordinated contraction of the ventricles is lost

Appearance = No P, QRS, or T waves // may be coarse of fine VF

Question 18

What occurs on an ECG to identify Asystole (cardiac arrest)?

Answer 18

Flat line on the ECG representing death and electrical silence

Question 19

What are the 4 types of Heart Blocks?

Answer 19

• First Degree AV Block
• Second Degree AV Block, Type 1 (Wenkebach)
• Second Degree AV Block, Type 2 (Mobitz)
• Complete Heart Block

Question 20

What occurs on an ECG to identify First Degree AV Block?

Answer 20

“if R is far from P, then it is first degree”
- slow of the impulse between the SA and AV node
- prolonged PR interval

Question 21

What occurs on an ECG to identify Second Degree AV Block, Type 1 (Wenkebach)?

Answer 21

• Progressively lengthening PR intervals until a beat is dropped aka. QRS Complex