Week 3 Cardio Flashcards Preview

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Flashcards in Week 3 Cardio Deck (21):
0

What does a P wave indicate?

Atrial depolarisation

1

What does a Q wave indicate?

Depolarisation of the septum

2

What does an R wave indicate?

Main depolarisation of the ventricles

3

What does an S wave indicate?

Depolarisation of the last remaining myocytes in the ventricles

4

What does a T wave indicate?

Repolarisation of the ventricles

5

What is the PQ interval?

The delay in conduction from the AV node to the ventricles

6

What does the QT interval represent?

The time taken for depolarisation and Repolarisation of the ventricles
(Ventricular systole + diastole)

7

What direction does depolarisation occur in the septum?

Base to apex, and left to right

8

Why does the T wave record a positive deflection if it is a negative charge?

Repolarisation is negative, but because it is a negative charge moving towards a negative electrode, it records an upwards deflection

9

What does isolectric mean?

No net movement of current. This can be either when the cell is either completely depolarised or completely repolarised.

10

Where are the electrodes of lead 1 positioned?

Left arm and right arm

11

Where are the electrodes of lead 2 positioned?

Left leg, right arm

12

Where are the electrodes of lead 3 positioned?

Left arm, left leg

13

What angle is lead 1?

Zero degrees

14

What angle is lead 2?

60 degrees

15

What angle is lead 3?

120 degrees

16

What angle is aVF?

90 degrees

17

What angle is aVR?

210 degrees

18

What angle is aVL?

-30 degrees

19

What does the 'mean electrical axis of the heart' refer to?

The direction where most of the flow of current is heading. This is calculated by the ECG machine and is recorded as the different deflections.

20

What is a biphasic deflection?

When the current is moving approximately perpendicularly to the angle of the lead. It will record an upward and downward deflection