the normal ECG

Question 1

what is an ECG

Answer 1

a time voltage graph o electrical conduction through the heart

Question 2

what kind of cells does an ECG record

Answer 2

myocardial cells as they are on the surface

Question 3

what is needed to record pacemaker cells activity

Answer 3

intracardial ECG

Question 4

what produces a positive reading on the ECG

Answer 4

movement of current towards the sensor

Question 5

what doe gap junctions allow cardio myocytes to do?

Answer 5

rapid impulse transmission from cell to cell

Question 6

what does the p wave indicate?

Answer 6

atrial depolarisation

Question 7

what does the PR interval indicate

Answer 7

time for the impulse to leave the SAN, travel through the atria, reach the AVN and start depolarising the ventricles - the majority of this time is spent in the AVN to allow for ventricular filling

Question 8

what does the ST segment indicate?

Answer 8

isoelectric portion - the time from ventricular depolarisation to repolarisation

Question 9

what does the QT interval indicate

Answer 9

the time from ventricular depolarisation to repolarisation

Question 10

why is atrial repolarisation not seen?

Answer 10

it is slow and diffuse

Question 11

what leads is the T wave normally negative in?

Answer 11

aVR, V1

Question 12

which are the bipolar leads

Answer 12

I, II, III

Question 13

which are the augmented limb leads

Answer 13

aVR, aVL, aVF

Question 14

which are the chest leads

Answer 14

V1-V6

Question 15

what leads show the inferior aspect of the heart

Answer 15

II, III, aVF

Question 16

what leads show the anterior aspect of the heart

Answer 16

V1-V6

Question 17

what leads show the lateral aspect of the heart

Answer 17

V5, V6, I, aVL

Question 18

what does left axis deviation indicate

Answer 18

LV hypertrophy or conduction defecit

Question 19

what does right axis deviation indicate

Answer 19

RV hypertrophy

Question 20

right axis deviation on an ECG

Answer 20

I -ve QRS, II +ve QRS

Question 21

left axis deviation on an ECG

Answer 21

I +ve QRS, II -ve QRS

Question 22

what leads does the R coronary artery relate to?

Answer 22

II, III, aVF (inf)

Question 23

what leads does the L anterior descending artery relate to?

Answer 23

V1,V1 (septal, ant)

Question 24

what leads does the L anterior descending artery relate to?

Answer 24

V3, V4 (ant)

Question 25

what leads does the circumflex artery relate to?

Answer 25

aVL, I, V5, V6

Question 26

what should be commented on when reading an ECG (6)

Answer 26

the basics, rate, rhythm, axis, waves, interval

Question 27

what is standard speed and calibration

Answer 27

speed - 25mm/mV; calibration - 10mm/mV

Question 28

why is calibration important

Answer 28

if not checked then could confuse for other conditions e.g. LV hypertrophy or pericardial effusion