ECGs

Question 1

ST elevation in V1 - V6

no reciprocal depression

Answer 1

Anterior MI

affecting Left Anterior Descedning artery

Question 2

ST elevation in V1 - V4

no reciprocal depression

Answer 2

Septal MI

lesion is in the septal branches of the LAD

Question 3

ST elevation in I, aVL, V5 and V6

reciprocal depression in II, III, aVF

Answer 3

Lateral MI

circumflex artery +/- marginalis

Question 4

ST elevation in II, III, aVF

reciprocal depression in I and aVL

Answer 4

inferior MI

usually right coronary artery

(20% are cimcumflex instead)

Question 5

high R with ST depression in V1 - V3 (>2mm)

high R in V1-V3 with ST depression V1-V3 > 2mm (mirror view)

Answer 5

Posterior MI

circumflex artery

Question 6

Inferior Leads

Answer 6

II

III

aVF

Question 7

Lateral Leads

Answer 7

I

aVL

V5

V6

Question 8

what does aVR reflect?

Answer 8

the Left Main

Question 9

Septal Leads

Answer 9

V1

V2

Question 10

Anterior Leads

Answer 10

V3

V4

Question 11

Position of the Chest Leads

Answer 11

V1 = right 4th ICS

V2 = left 4th ICS

(V3 = between those two)

V4 = 5th ICS, mid-clavicular (under breast)

(V5 = between these two)

V6 = transverse from V4 but mid-axillay

Question 12

Rate by Square Counting

Answer 12

1 square = 300

2 squares = 150

3 squares = 100

4 squares = 75

5 squares = 60

6 squares = 50

7 squares = 43

8 squares = 37

Question 13

Normal PR interval

Answer 13

120 - 200 ms

3 - 5 small squares

Question 14

Normal QRS Complex

Answer 14

< 110 ms

< 3 small squares

Q < 25% R height

Question 15

Normal QT interval

Answer 15

< 450 ms for men

11 small squares

< 460ms for women

11.5 small squares

Question 16

Tall P wave

Answer 16

P pulmonale

right atrial enlargement

Question 17

bifid P wave

Answer 17

P mitrale

left atrial enlargement

Question 18

inverted P wave

Answer 18

ectopic atrial rhythm (not from SA node)

Question 19

Judging QRS morphology

Answer 19

• pathological Q waves?
• LVH or RVH?
• width
• R wave progression (getting large from V1 to V5 then V6 is smaller)

Question 20

Normal R wave progression

Answer 20

progressively taller V1 - V5

lack of R wave progression suggests damaged ventricle wall (previous MI)

Question 21

Normal T waves

Answer 21

upright in all except aVR, V1

inverted can be normal in III if QRS is also inverted

1 - 2 big squares tall

Question 22

Normal ECG Calibration

Answer 22

25mm/s =

• 5 big squares in 1 second
• 1 big square is 200ms
• 1 small square is 40ms
• 300 big squares = 1 min

2 big squares = 1mV

Question 23

Normal P wave

Answer 23

< 3 small accross

< 2.5 small high

Question 24

Rates from R waves

Answer 24

• 1 big square = 300
• 2 = 150
• 3 = 100
• 4 = 75
• 5 = 60
• 6 = 50

Question 25

persistent ST elevation in anterior leads

Answer 25

left ventricular aneurysm

Question 26

Tall S waves in I

Deep Q waves in III

Inverted T waves in III