EKG

Question 1

What are the steps of EKG interpretation?

Answer 1

1. Rate
2. Intervals
3. Axis
4. Rhythm
5. Hypertrophy
6. Infarction / Ischemia
7. Other

Question 2

How do you determine rate?

Answer 2

Measure R-R intervals or count the # of complexes and multiply by 6

Question 3

How do you measure rate using the RR interval?

Answer 3

use the 300 – 150 – 100 – 75 – 60 – 50 - 40

Question 4

What are the intervals we measure?

Answer 4

PR, QRS, Qtc

Question 5

What is the normal PR interval?

Answer 5

0.12 - 0.20 seconds

Question 6

What does one “itty-bitty” box count for? what about one big box?

Answer 6

itty-bitty box = 0.04 seconds

big box = 0.20 seconds

Question 7

What is the normal QRS interval?

Answer 7

0.06 - 0.10 seconds

Question 8

What is the normal QTc interval?

Answer 8

0.30 - 0.46 seconds or as long as the Qt interval is less than half the preceding R-R interval

Question 9

What is normal axis?

Answer 9

between -30 and 90

Question 10

Where is the axis if lead I is positive and lead II is positive?

Answer 10

Normal axis! -30 to -90

Question 11

Where is the axis if lead I is positive and lead II is negative?

Answer 11

left axis deviation! -30 to 270

Question 12

Where is the axis if lead I is negative and lead II is positive?

Answer 12

right axis deviation! 90 to 150

Question 13

Where is the axis if lead I is negative and lead II is negative?

Answer 13

no mans land! 150 to 270

Question 14

PR interval more than 0.20 seconds with 1:1 conduction

Answer 14

1st degree AV block

Question 15

PR interval lengthens followed by completely blocked P wave

Answer 15

2nd degree AV block type 1

Question 16

PR interval stays the same, P waves are intermittently blocked

Answer 16

2nd degree AV block, type 2

Question 17

P waves are completely blocked, QRS originates independently

Answer 17

3rd degree AV block

Question 18

Right atrial hypertrophy

Answer 18

Either:
P wave in any limb lead is more than 2.5 mm
P wave in V1 is biphasic and the initial portion is the largest

Question 19

Left atrial hypertrophy

Answer 19

Either:
P wave in lead II is notched with > 0.04 sec between peaks
P wave in V1 is biphasic and the terminal portion is the largest with usually a negative deflection

Question 20

Right ventricular hypertrophy

Answer 20

Right axis deviation AND R wave in V1 is more than 7mm tall

Question 21

Left ventricular hypertrophy

Answer 21

Cornell criteria: R wave in aVL + S in V3 = > 24 in men or > 20 in women
Any R + S in precordial leas >45mm
R wave in V5 more than 26mm
R wave in aVL at least 12 mm (most specific)

Question 22

Ischemia

Answer 22

T waves biphasic with or without ST depression

Question 23

LBBB

Answer 23

QRS greater than or equal to 0.12 sec
Broad R waves in I, V5 and V6
    - ST depression and T wave inversion in these leads
         -large S wave in V1/V2
         -possible left axis shift

Question 24

Does having LBBB affect any other diagnosis?

Answer 24

hypertrophy and infarct

Question 25

RBBB

Answer 25

QRS equal to or more than 0.12 sec

rsR’ in V1 and V2, typically second R larger

Question 26

Diffuse Upward Concave ST segment elevation except for aVR with no reciprocal ST depressions

Answer 26

pericarditis

Question 27

Tall, narrow, peaked T wave with possible QT shortening

Answer 27

K+ = 5.5 - 6.5 mEq/L

Question 28

flattened wide P waves, widened QRS

Answer 28

K+ = 6.5 - 7.5 mEq/L

Question 29

Loss of P waves, very wide QRS, VT, VF, asystole

Answer 29

K+ > 7.5 mEq/L

Question 30

Prominent U waves, flat T waves, big P waves

Answer 30

hypokalemia

Question 31

Sinus Tach

S1Q3T3

Answer 31

PE

Question 32

A fib or sinus brady, or osborne waves

Answer 32

hypothermia