Exam 1 review

Question 1

Identify the normal electrical power source of the heart

Answer 1

Pacemaker cells in SA node

Question 2

Differentiate the physiology of a pacemaker action potential from a cardiomyocyte action potential

Answer 2

Pacemaker=spontaneous

Cardiomyocyte=nonspontaneous

Question 3

Recall the typical rates of depolarization of pacemaker cells in the sinus node (SA node), the atrioventricular node (AV node) and the ventricles

Answer 3

SA node=60-100
AV node=40-60
Ventricles=20-40

Question 4

Recognize what the following wave forms represent on a cycle of cardiac contraction and relaxation within the EKG

a. P wave
b. Q wave
c. QRS complex
d. T wave

Answer 4

P-wave=both atria depolarize
Q-wave=septal depolarize
QRS-complex=ventricles depolarize
T-wave=ventricles repolarize

Question 5

Recognize the following conditions either by analyzing an EKG/rhythm strip or by description

a. ST elevation myocardial infarction
b. Cardiac ischemia
c. Right, left and biatrial enlargement

Answer 5

STEMI=1mm height in limb leads, 2mm height in precordial leads
Ischemia=ST depression
RA enlargement=enlarged P wave
LA enlargement=wide P wave, notched
biartial enlargement=shark fin

Question 6

Recall which leads correspond to each of the following areas of the heart

a. Anterior
b. Inferior
c. Left lateral
d. Right ventricular

Answer 6

Anterior=V2, V3, V4
Inferior=II, III, aVF
Left Lateral=I, aVL, V5, V6
Right Vent=aVR, V1

Question 7

Recall how many seconds one small square represents on EKG paper

Answer 7

0.04 sec

Question 8

Recall how many seconds one large square represents on EKG paper

Answer 8

0.20 sec

5 small squares long and high

Question 9

Prolonged PR boxes and time?

Answer 9

> 0.2 sec
1 big box
Type of heart block!

Question 10

Prolonged QT? Normal is ___ between QRS complexes

Answer 10

Normal <1/2 between two QRS complexes. 40% of cardiac cycle. Inversely proportial to heart rate.

Question 11

Pathologic Q wave means? Measurement?

Answer 11

Irreversible myocardial damage.

≥1/3 height of R wave

Question 12

Poor R wave progression means what is enlarged?

Answer 12

RV.

Question 13

R Wave progression defined as

Answer 13

Pattern of progressively increasing R wave amplitude moving right to left in the precordial leads

Question 14

List the 5 criteria for normal sinus rhythm

Answer 14

1. P wave before every QRS
2. Regular rhythm
3. Rate between 60-100bpm
4. Normal PR int (0.12-0.2)
5. Normal QT-int (<1/2 way between two QRS complexes)

Question 15

Wide QRS defined? Due to?

Answer 15

Impulses generated in ventricles or abberant pathway through ventricles
>0.1 sec=wide

Question 16

Normal QRS time?

Answer 16

0.06-0.1sec

Question 17

Identify if an EKG shows right axis deviation

Answer 17

Lead I=down

aVF=up

Question 18

Identify if an EKG shows left axis deviation

Answer 18

Lead I=up

aVF=down

Question 19

Recall the criteria for right ventricular hypertrophy

Answer 19

R>S in V1
S>R in V6
Poor R wave progression
R axis deviation (I=down, aVF=up)

Question 20

Recall the criteria for left ventricular hypertrophy

Answer 20

R amplitude in V5 or V6 + S in V1 or V2=7 boxes = >35mm tall