EKG intro

Question 1

what is the direction of electrical current flow?

Answer 1

from negative to positive

Question 2

what axis is aVR?

Answer 2

-150 (or 10 o’clock)

Question 3

what axis is aVL?

Answer 3

-30 (or 2 o’clock)

Question 4

what axis is I?

Answer 4

0 (or 3 o’clock)

Question 5

what axis is II?

Answer 5

60 (or 5 o’clock)

Question 6

what axis is aVF?

Answer 6

90 (or 6 o’clock)

Question 7

what axis is III?

Answer 7

120 (or 7 o’clock)

Question 8

electrical force directed toward + pole of a lead generates what deflection?

Answer 8

positive deflection in that lead

Question 9

what determines magnitude of deflection?

Answer 9

how parallel electrical force is to lead: more parallel = greater magnitude of deflection

Question 10

what does perpendicular force look like?

Answer 10

flat line

Question 11

what does 1 mm (one small box) represent?

Answer 11

.1 mV

Question 12

how long is 1 mm?

Answer 12

.004 sec (5 small boxes/1 big box = 200 ms)

Question 13

normal EKG findings include?

Answer 13

1. every P followed by QRS
2. upright P in I, II and III
3. PR interval between 120 and 200 ms
4. HR btwn 60-100 bpm

Question 14

how to calculate HR?

Answer 14

1500/(# of small boxes between 2 QRS complexes)

Question 15

alternate sequence to count with?

Answer 15

300 - 150 - 100 - 75 - 60 - 50

Question 16

HR calc for irregular rhythm?

Answer 16

of QRS during 6 seconds, multiply by 10

Question 17

normal QRS axis values?

Answer 17

-30 degrees to +90 degrees

Question 18

which leads determine this most easily?

Answer 18

evaluate QRS in I and II (or I and aVF). if net QRS is + (and if II is most +) it’s normal

Question 19

LVH findings?

Answer 19

ST segment depression, T wave inversion in leads with prominent R wave

Question 20

RVH findings?

Answer 20

shifts QRS vector to R.

Question 21

fascicular block findings?

Answer 21

?

Question 22

RBBB findings?

Answer 22

V1: 2nd wide R wave (RSR) aka rabbits’ ears. also inverted T. but overall positive.
V6: late slurred S wave (overall broad QRS)

Question 23

LBBB findings?

Answer 23

V1: deep wide S waves, looks like a W (negative)
V6: broad M. no Q waves.

Question 24

criteria for RBBB?

Answer 24

unifascicular block.

1. QRS complex greater than .12 sec
2. RsR (M shaped/rabbits’ ears) QRS in lead V1
3. widened/slurred S wave in I and V6

Question 25

criteria for LBBB?

Answer 25

bifascicular block.

1. QRS greater than .12 sec
2. widened or slurred R wave of I and V6 (broad R, no Q)
3. prominent QS or rS in V1 (broad S)

Question 26

acute anterolateral MI on EKG?

Answer 26

STEMI. ST elevation in I, aVL, V2 thru V6