Week 5

Question 1

Explain the P wave.

Answer 1

• artrial depolarisation
• upright, rounded and symmetrical
• peaked p waves reflect atrial enlargement

Question 2

Explain the PR interval.

Answer 2

• distance from the beginning of the p wave to the beginning of the QRS complex
• represents time of impulse from SA node to ventricles

Question 3

Explain the QRS complex.

Answer 3

• depolarisation from AV node throughout ventricles
• the first small downward deflection is the “Q” wave
• first upward deflection is the “R” wave
• deflection following the R wave is the “S” wave

Question 4

Explain the ST segment.

Answer 4

• from the end of QRS to beginning of T
• relationship to baseline is important
• ST depression may indicate myocardial ischaemia
• ST elevation may indicate myocardial injury
• connects the QRS complex to the T wave

Question 5

Explain the T wave.

Answer 5

• ventricular repolarisation
• should look round and smooth
• tall, inverted, or pointy T’s may indicate myocardial injury or hyperkalaemia
• inverted or “flattened” T’s may indicate ischaemia
• notched T’s may indicate pericarditis

Question 6

What part of the heart are leads II, III, AVF looking at?

Answer 6

Inferior wall left ventricle

Question 7

What part of the heart are leads I, AVL, V5 and V6 looking at?

Answer 7

Lateral wall left ventricle

Question 8

What part of the heart are leads V1 and V2 looking at?

Answer 8

Intraventricular septum.

Question 9

What part of the heart are leads V3 and V4 looking at?

Answer 9

Anterior wall left ventricle.

Question 10

What is the difference between a temporary and permanent pacemaker?

In your own time, look up the purpose and indications for a pacemaker.

Answer 10

Temporary

• in temporary pacing the energy source is located outside the heart.

Permanent

• in permanent pacing, the pacemaker is inserted under the skin.

Question 11

What are potential complications of pacemaker insertion?

Answer 11

• haematoma
• infection
• lead dislodgement
• pneumothorax