L3: Axis

Question 1

A (+) aVF means the axis is

Answer 1

0 to 180

Question 2

A (+) lead I means the axis is

Answer 2

90 to (-)90

Question 3

Leads used to assess QRS axis

Answer 3

I and aVF

Question 4

The tallest QRS in the frontal plane

Answer 4

The axis is in this direction

Frontal: I, II, III, aVR, aVF

Question 5

An equiphasic QRS complex

Answer 5

The axis is perpendicular to that lead
Find a (+) lead which is perpendicular, it points in that direction

Question 6

Hexaxial reference

I=aVF

Answer 6

45

Question 7

Hexaxial reference system

I>aVF

Answer 7

0 to 45

Question 8

Hexaxial reference system

aVF>I

Answer 8

45 to 90

Question 9

Normal p wave axis

Answer 9

0-75

Question 10

Normal t wave axis

Answer 10

close to QRS axis

Question 11

R wave in Lead II > R wave in aVF

The axis is

Answer 11

Normal

Question 12

Strong left axis deviation

Answer 12

R wave in aVL>I

Question 13

Strong right axis deviation

Answer 13

R wave in III>aVF

Question 14

biphasic p wave in

Answer 14

V1

Question 15

Assess atrial enlargement in leads

Answer 15

II and V1

Question 16

RAE criteria

Answer 16

Amplitude >2.5 mm

Initial component of P wave in a biphasic V1 is larger t

Question 17

LAE criteria

Answer 17

Duration >.10 secs

Terminal portion of P wave in V1 is negative with a duration of >.04 and depth >1 mm

Often associated with notched P wave on Lead II→ not sufficient for diagnosis alone

Question 18

LVH criteria

Answer 18

1. Sum of deepest S in V1/V2 plus tallest R V5/V6 = >35 mm
2. R in aVL > 11 mm
3. R in Lead I plus S in Lead II = >25 mm

Question 19

RVH criteria

Answer 19

1. Right axis deviation > +90
2. R wave > S wave in V1
   → R wave usually > 7 mm
3. S wave > R wave in V6