ECGs

Question 1

What are the lateral leads and what coronary arteries do they correspond to?

Answer 1

I, aVL, V5 and V6

Left circumflex and diagonal of LAD

Question 2

What are the inferior leads and what coronary arteries do they correspond to?

Answer 2

II, III and aVF

Right coronary artery via posterior descending artery

Question 3

What are the anterior/ septal leads and what coronary arteries do they correspond to?

Answer 3

V1 to V4

LAD

Question 4

What is the normal range for the P wave?

Answer 4

80-100ms

Question 5

What is the normal range for the PR interval?

Answer 5

120-200 ms

3-5 little squares

Question 6

What is the normal range for the QRS complex?

Answer 6

60-109 ms

>120 = BBB

Question 7

What is the normal range for the T wave?

Answer 7

120-160 ms

Question 8

how much is each little square?

Answer 8

40ms

Question 9

What are the axis for each lead?

Answer 9

I= 0
II= +60
III = +120
aVF = +90
avL= -30
aVR = -150

Question 10

What is the normal axis?

Answer 10

-30 to +90

Question 11

What is the PR interval and what is the QT interval?

Answer 11

start P to beginning QRS

begin Q to end of T

Question 12

What is the normal QT interval length?

Answer 12

QTc is prolonged if > 440ms in men or > 460ms in women

Question 13

What is the normal number of big squares between QRS complexes?

Answer 13

Either 3, 4 or 5 squares (100, 75, 60 BPM)

Question 14

What indicates LAD?

Answer 14

lead I positive and lead II negative (leaving each other)

Question 15

What indicates RAD?

Answer 15

Lead I negatives and lead III positive (reaching towards each other)

Question 16

What do you find in RBBB?

Answer 16

rSR/ rR waves in V1 and V1 and V2 “bunny ears”

prolonged QRS and T wave inversion V1

Question 17

What can cause RBBB?

Answer 17

Can be normal; R heart overload eg PE, pulomary htn, ASD, lung disease

Question 18

How do you diagnose VT over SVT?

Answer 18

If V1-V6 is made of monophasic S or R waves = VT
If have RS complexes that are over 100 ms = VT
If there is any AV disocciation (i.e. P waves separate/ superimposed onto QRS)/ fusion beats

Question 19

What occurs to the P waves during left atrial enlargement?

Answer 19

P-mitrale in lead II where the P wave has a second hump in a “M” shape

Question 20

Which lead is best for looking at the atria?

Answer 20

lead II

Question 21

What occurs to the P waves during right atrial enlargement?

Answer 21

P-pulmonale, increased P wave amplitude on lead II

Question 22

From V1 to V6 which waves get bigger/ smaller?

Answer 22

R waves get bigger and S waves get smaller

Question 23

What do you see on LBBB?

Answer 23

Unlike RBBB always shows organic heart disease!!

LV depolarisation delay → broad QRS (over 3 squares/ 120ms) in lateral leads

Broad monophasic (no Q or S waves) in leads I, avL, v5 and v6 (laterals),

ST and T negative in I and aVL, positive in v1 to 3

Dominant S wave in V1

Prolonged R wave peak time > 60ms in leads V5-6

Question 24

What would you see on wolf-parkinson-white ecg?

Answer 24

Upsloping of QR (delta wave)

Short PR interval

Question 25

What is an epsilon wave?

Answer 25

Important ECG sign which indicates arrythmogenic right ventricular cardiomyopathy which can be cause of sudden death --> bump between S and T wave on V1 and V2

Question 26

What is the osborn wave?

Answer 26

aka J wave of hypothermia | notch between R and T

Question 27

What is brugada syndrome?

Answer 27

Sodium channelopathy in heart Coved ST segment elevation >2mm in >1 of V1-V3 followed by a negative T wave. WITH VF/ fhx sudden cardiac death/ syncope/ nocturnal agonal respiration

Question 28

What ECG changes occur post MI - in terms of hrs to days to months

Answer 28

hrs: ST elevation hrs to days: Loss R wave, Q wave formation days: T wave inversion weeks to months: pathological Q waves

Question 29

Describe a pathological Q wave

Answer 29

Q waves that are deep and broad in aVF, V1-3 are pathological ALSO if deeper than 2 small squares and wider than 1 small square

Question 30

What would you see on a postero/lateral STEMI?

Answer 30

ST depression in V1 to V4 as a mirror image of ST elevation that would occur if there were V7 to V9 leads around the back

Question 31

What are some other causes of ST elevation?

Answer 31

benign early repolarisation | pericarditis (saddleback and global)

Question 32

Appearance of hypokalaemic ecg?

Answer 32

flattened T waves | prominent U wave

Question 33

Appearance of hyperkalaemic ecg?

Answer 33

QRS broad T waves peaking loss P prolonged PR

Question 34

How does digoxin effect ecg?

Answer 34

Bowl shaped inverted T wave

Question 35

What is Left anterior hemi-block?

Answer 35

Left axis deviation; rS (small r and large S) in II, III and aVF; qR complexes in leads I, aVL; QRS <120 ms

Question 36

What is Left posterior fascicular block?

Answer 36

Left posterior fascicular block: right axis deviation; rS complex I and avL, qR in II, III, aVF

Question 37

What is Bifasicular block?

Answer 37

RBBB with left anterior fascicular block (LAFB), manifested as left axis deviation (LAD) OR RBBB and left posterior fascicular block (LPFB), manifested as right axis deviation (RAD) in the absence of other causes

Question 38

What is trifasicular block?

Answer 38

Trifasicular block: bifascicular block and AV block