EKG I- Hypertrophy, Enlargement, Axis Deviations

Question 1

NORMAL MEASUREMENTS
- PR interval
- QRS intervals
- QT interval

Answer 1

PR= 0.12-0.20 seconds

QRS= .06 - 0.10 seconds

QT= 40% of R to R interval (<0.40 seconds)

Question 2

Enlargement- define and causes

Answer 2

• dilation of a chamber
• occur due to volume overload or valvular ds

(accommodating large amt of volume)

Question 3

Hypertrophy- define and causes

Answer 3

• inc of muscle mass in myocardium
• occurs due to inc pressure load

( HTN, aortic stenosis)

Question 4

are hypertrophies or enlargements more susceptible to ischemia?

Answer 4

hypertrophy.

more muscle but no new blood flow can cause a higher risk of ischemia.

Question 5

R Atrial Enlargement

Answer 5

Lead II- inc amplitude

Lead V1- higher peak in FIRST half (biphasic wave)

Question 6

L Atrial Enlargement

Answer 6

Lead II- inc duration of wave >0.12 seconds

Lead V1- deeper peak in SECOND half of wave >1mm

Question 7

R Ventricular Hypertrophy

Answer 7

VI R wave > S wave
V6 S wave > R wave

may also see…
- larger R waves in V1, 5, and 6
- lead I more neg than pos

Question 8

L Ventricular Hypertrophy

Answer 8

R wave amplitude from V5 or 6 + S wave amplitude from V1 or 2 >35 mm

may also see..
- inc R wave over precordial leads over LV (V1,2,5,6)
- inc S waves over precordial leads over RV

Question 9

Axis Deviations- what 2 leads should you look at?

Answer 9

lead I and aVF

Question 10

Normal axis

Answer 10

Lead I- pos
Lead aVF- pos

Question 11

LAD axis

Answer 11

Lead I- pos
Lead aVF- neg

Question 12

RAD axis

Answer 12

Lead I- neg
Lead aVF- pos

Question 13

Extreme Axis

Answer 13

Lead I- neg
Lead aVF- neg