EKG test

Question 1

How much time is one small box? One big box?

Answer 1

40 msec (.04 sec)
200 msec (0.2 sec)

Question 2

What is the height of one small box?

Answer 2

0.1 mm

Question 3

What is the trick for determining rate? What’s the math for determining rate?

Answer 3

Count the big boxes between each peak (300, 150, 100, 75, 60, 50); count the number of big boxes, and then do 300/that number

Question 4

If something originates in the SA node, what rhythm is it?

Answer 4

Sinus rhythm!

Question 5

What are the best leads to look at the p-wave?

Answer 5

leads II and V1 (if you see p-waves before each QRS, it’s sinus rhythm

Question 6

What are the pacemaker rates in the SA, AV, and ventricules?

Answer 6

SA = 60-100; AV = 40-60; Ventricle = 20-40

Question 7

What is a normal QRS?

Answer 7

0.08 - 0.10 seconds (should be less than 1 big box!)

Question 8

What is a wide QRS?

Answer 8

120 msec (120 is three small boxes)

Question 9

If the rhythm is ventricular, what will it do to the QRS?

Answer 9

cause a wide QRS

Question 10

What are the 2 causes of a wide QRS?

Answer 10

rhythm started in the ventricle OR there is RBBB (started in the atrium in this case, just takes longer to complete depolarization due to the BBB)

Question 11

What are the best leads for looking at axis?

Answer 11

leads I and aVF

Question 12

What is the most common cause of AV dysfunction?

Answer 12

Age (AV node takes more time to think about what’s happening - you will see a prolonged PR interval)

Question 13

What’s a normal PR interval?

Answer 13

120msec - 200msec (3-5 small boxes)

Question 14

What’s a normal QT interval?

Answer 14

400 - 430 msec (greater than 2 big boxes)

Question 15

What is the QTc? What’s high for a woman, man?

Answer 15

QT/(square root RR interval); 460, 440

Question 16

Atrial flutter causes ectopic reentrant activity, that usually causes a rate in the atrium of __, but the __ cuts in half.

Answer 16

300; AV node (ventricular rate ends up being about 150)

Question 17

Name 3 causes of R axis deviation

Answer 17

1) RVH; 2) PE (puts pressure or increased volume on right side); 3) RBBB

Question 18

Name 3 causes of L axis deviation

Answer 18

1) LVH (HTN or AS); 2) LBBB; 3) MI (puts pressure or increased volume on L side)

Question 19

How do you diagnose RBBB?

Answer 19

QRS gt 120; RsR’ in V1; Slurred S in V6

Question 20

What leads point to an inferior wall STEMI? Septal? Lateral? Anterior?

Answer 20

II, III, AVF
Septal: V1, V2
Anterior: V3, V4
Lateral: I, AVL V5, V6

Question 21

What are reciprocals to look for in STEMIs

Answer 21

inferior vs lateral
anterior vs posterior
septal vs none

Question 22

What defines a STEMI?

Answer 22

Need to see ST segment elevations in at least 2 contiguous leads of 2mm in precordial leads or 1mm in limb leads

Question 23

How do you determine LVH?

Answer 23

Add S in V1 and R in V5 or V6 and if sum is gt 35 = about 7 big boxes, you have LVH

Question 24

If V1 is positive what’s the next question and what could it mean?

Answer 24

Is QRS narrow or wide?
If narrow think RVH (also RVH with strain shows an inverted T-wave)
If wide think RBBB

Question 25

Wolff Parkinson White has an accessory pathway that bypasses the AV node reaching the ventricles faster but causing ventricular depolarization (instead of through AV) - what does this mean for PR and QRS?

Answer 25

Short PR (since AV node is not being used and that slows conduction down) and widened QRS (since ventricular contraction is slow)

Question 26

How do you tx pt with WPW?

Answer 26

Procainamide

Question 27

Wide complex tachycardia should make you think what?

Answer 27

Vtach (torsades too)

Question 28

Diffuse ST elevations and __ are diagnostic of __. __ lead will be the opposite of the others.

Answer 28

PR depression; pericarditis; aVR