EKG Basics

Question 1

What are the steps to review EKG?

Answer 1

Rate- double check dashes for 6 vs 10s strip
Rhythm
Sinus
Pwave B4 QRS
Intervals-PR, QRS, QT
Ischemia+Infart
Hypertrophy
Axis
Confirm looking at LII strip
Confirm waves with other leads

Question 2

What is cardiac conduction system pathway and sinus rate at each pathway?

Answer 2

SA node-60-100
Atrial Syncytium- 60-80(APs, along the surface of the muscle fiber
Atrial Junctional fibers- 40-60
AV node-40-60
Bundle of His
L+R Branches
Purkinje Fibers
Ventricular Syncytium 20-40- Endo 1st, External 2nd

Question 3

Describe what it means if HR is 50bpm, and not an athlete?

Answer 3

Signal is coming mainly from AV node. NOT SA.
Athletes HR adapts usual now 50-60 avg.
IF one part not firing, another will back up, BUT HR will be less.

Question 4

Delay is 0.12s due to time needed to fill ventricle before atria and ventricle contract? What node is this?

Answer 4

Atrioventricular junction/ AV node

Question 5

This is the primary pacemaker node of heart d/t its automaticity?

Answer 5

Sinoatrial node
Sinus node
Normal 60-100, starts here

Question 6

How do you set up the leads on the body to get a transverse plan EKG of heart?

Answer 6

Precordial leads
Remove all 'noise'- hair, wire bra, sweat, dried leads
V1- R 4th ICS -nipple level
V2- L across from V1
V3- Lbtwn V2 and V4
V4- L 5th ICS midclavic- below nipple
V5- L 5th ICS btwn V4 and V6, ant axillary
V6- L 5th ICS ANt midaxillary IC

Question 7

How do you set up the leads on the body to get a FRONTAL plane EKG of heart?

Answer 7

Limb leads
AVR- R limb or clavicle
AVL- L limb or clavicle
AVF- Hip or ankle
I= volts from AVR and AVL
II= volts from AVL and AVF
III= volts from AVF and AVR

Question 8

Why is the axis of heart important?

Answer 8

Axis determine direction of depolarization.
AVL -30deg
I 0deg
II +60
AVF +90
III +120
AVR -150
Primarily LIMB leads I, AVF are used to determine AXIS

Question 9

Describe steps for AXIS

Answer 9

1. Find biphasic- means electricity is + and - deflection at that lead
2. Find Lead 90 to biphasic lead= IF that lead is + or - that is AXIS direction
3. Confirm with Lead I + AVF
4. If no biphasic- Find I+ AVF deflection
   Tips- which deflection is more + or -
   Tips- confirm with II, since that lead is NORMAL axis of 60deg

Question 10

Describe the PQRSTU intervals and segments of each in relation to heart pump and heart electricity?

Answer 10

P- wave= atrial depolarization + contraction
Q- interventricular septum depolar
R- ventricular depolar
S- ventricular small fibers
T- ventricuclar +atrial repolarization+ relaxes
U- RARE, if see a wave, likely p-wave. U is repolar of Purkinje fibers

Question 11

Describe the height and width of box in a strip.

Answer 11

Width of 1 small box= 0.04s, big box 0.20s

Ht- 1 sm bx= 1mm, .1mV

Question 12

Describe what each interval and segment represent and Normal time of each.

Answer 12

PR segment- time from atria to ventric contraction
2-3 bx. P to QRS (sometime Q missing-normal)

PR interval- wave and time to QRS 3-5 boxes- N.0.12-0.20sec. BEg P- Beg QRS- time from atria to AV junction

QRS interval- ht in volts, narrow is normal. .08-.12, 2-3 bx., time to spread in ventricle. IF less, benign. Narrow or Wide

QT interval- wave and time beg Q to end of T, 8-9bx- Ventric Depolar and Repolar

ST segment- line, end of S to BEG. of T, time to repoloarize, relax

ST interval- time to S to END of T

Question 13

These are the cause of what Axis deviation;
Normal in children
RV enlarge
Lateral MI
L tension pneumothorax
PE
L post hemiblock
COPD

Answer 13

Right AXIS

Question 14

These are the cause of what Axis deviation;
Normal d/t diaphragm elevation
LV enlarge
Inferior MI
R tension pneumothorax
Ventricular pacemaker
L ANT. hemiblock

Answer 14

Left AXIS

Question 15

How do you determine AXIS w/ two thumbs up method?

Answer 15

LEAD I ,AVF= ++ NORMAL axis
LEAD I +, AVF - = LAD axis
LEAD I - , AVF+ = RAD
LEAD I - , AVF - = Indeterminate

Question 16

If there is 4 lines btwn the R-R peak waves and rhythm is regular, then What is the bpm?

Answer 16

Box method- 75
300- 1 bx
150- 2 bx
100- 3 bx
75- 4 bx
60- 5bx
50- 6bx
Steps: 1. start w/ R on a line 2. count thick black line 3. use box number ONLY for REGULAR rhtymn

Question 17

<60bpm and >100bpm is defined as

Answer 17

Sinus bradycardia- w/ P wave

Sinus tachycardia- w/ P wave, confirm with other lead

Question 18

What if the rate is slow or irregular (unevenly spaced) beat, how do you calculate rate?

Answer 18

Be mindful of 6sec or 10sec strip
Count R intervals
IF 6 sec strip R # x 10
IF 10 sec strip R# x 6= MC, look for dashes

Question 19

What is required for normal sinus rhythm?

Answer 19

P wave b4 every QRS, same morphology + size
Means impulse originates at SA- 60-100
P wave always upright in Lead I, II
INVerted in AVR

Question 20

What is evenly spaced R-R intervals?

Answer 20

Regular

Any IRRegular rhythm is AFIB until proven otherwise*

Question 21

During inspiration and expiration what should be seen?

Answer 21

Sinus arrhythmia
R-R shorter in inspire- less ventric expansion to fill, INC HR to match output squeezed by lung

R-R longer in expire- lung deflate, heart has space/time to fill, slower HR

Question 22

What is progressive lengthen of PR interval and then 1 drop in QRS?

Answer 22

AV 2nd degree block
delay from SA or Block of SA node
no p wave, may mean after QRS, not a U wave

Question 23

Pt is dizzy, SOB, feeling heart beat? What my be seen on EKG?

Answer 23

2nd degree block
PR interval same length
But 2 missing QRS