Axis and Chamber Enlarg

Question 1

Vectors vs Axis?

Answer 1

Vectors:
many small currents in varying directions,
LV vectors larger/longer than RV

Avis:
overall direction of sum of currents,
down and to left

Question 2

QRS Axis seen in what leads?

What direction is normal?

Answer 2

I and aVF

both positive (b/w Oº and +90º) 3:00 - 6:00

Question 3

Left Axis Deviation (LAD): QRS axis b/w?

Answer 3

Oº and -90º (noon - 3:00)

lead I upright, aVF down

Question 4

Right Axis Deviation (RAD): QRS axis b/w?

Answer 4

+90º and +180º (6:00 - 9:00)

lead I down, aVF upright

Question 5

QRS axis + in lead I, axis must be b/w what degrees?

Answer 5

-90º and +90º

noon - 6:00

Question 6

QRS axis + in aVF, axis must be b/w what degrees?

Answer 6

0º and +180º

3:00 - 9:00

Question 7

Extreme Axis Deviation: QRS axis b/w?

Answer 7

-90º and -180º (9:00 - midnight)

lead I down, aVF down

Question 8

If lead I and aVF uprights are =, QRS axis is?

Answer 8

+45º

Question 9

If lead I is + and > aVF, QRS axis is?

Answer 9

closer to lead I

Question 10

If aVF deflection is > lead I, QRS axis is?

Answer 10

closer to aVF

Question 11

If QRS complex is isoelectric, QRS axis is?

Answer 11

90º away from that lead

+ component = - component

Question 12

Causes of LAD?

Answer 12

L anterior hemiblock

LVH

Question 13

Causes of RAD?

Answer 13

(N) in kids and tall/thin adults

RVH

Question 14

Vertical heart is?

Answer 14

QRS axis points down toward +90º,

Tall/thin adults

Question 15

Horizontal hear is?

Answer 15

QRS axis points up to the left (closer to 0º or neg),

Obese, preggos

Question 16

Atrial enlargement seen where is ECG?

Answer 16

P waves (atrial depol)

Question 17

RAE appears as?

Answer 17

Lead I: P-wave amplitude > 2.5

Lead V1: P-wave biphasic w/ tall > low,
R-wave > S-wave

RAD

Question 18

LAE appears as?

Answer 18

P-wave duration > 0.10 sec
Lead II: P-wave notched (mitral)
Lead V1: biphasic w/ neg deeper than tall

Question 19

Vent hypertrophy seen where in ECG?

Answer 19

QRS

Question 20

Normal vent depol moves?

Answer 20

down to left and posteriorly

away from V1 -> R-wave should be small in V1

Question 21

RVH appears as?

Answer 21

RAD > +90º (due to thick R vent)

Lead V1: R-wave > S-wave

Question 22

LVH appears as?

Answer 22

Precordials: Sum of deepest S in V1 and V2 + tallest R in V5 or V6 > 35mm

aVL: R-wave > 11mm

Lead I/III: R in I + S in III > 25mm

LAD