EKG

Question 1

The EKG is

Answer 1

graphic representation of electrical conduction through the heart

Question 2

Conduction system

Answer 2

SA node-AV node-Bundle of His-Purkinje fibers-myocardium

Question 3

The isoelectric line is

Answer 3

the baseline-straight line from which the components of an EKG wave are defined

Question 4

P wave

Answer 4

Indicates atrial depolarization, or contraction of the atrium

• amplitude (height) is no more than 3 mm
• no peaking

Question 5

PR interval

Answer 5

Indicates AV conduction time

• measures from the beginning of the P wave to the beginning of the QRS
• normal duration time is 0.12 to 0.20 seconds

Question 6

QRS complex

Answer 6

indicates ventricular depolarization or contraction of the ventricles

• normally not longer than .10 in duration
• R waves are deflected positively and the Q and S waver are negative

Question 7

T wave

Answer 7

indicates ventricular repolarization

-rounded and asymmetrical

Question 8

ST segment

Answer 8

represents the time between the end of the contraction and repolarization

• normally not depressed
• may be elevated slightly in some leads (no more than 1 mm)

Question 9

Each small square on the EKG graft is

Answer 9

0.04 seconds

Question 10

One large square on EKG graft is

Answer 10

0.020 seconds (contains 5 small squares)

Question 11

30 squares equals

Answer 11

6 seconds

Question 12

1500 squares equals

Answer 12

1 minute

Question 13

Determine regular rhythm

Answer 13

measure from R to R

• if the rhythm varies by 0.12 seconds or more the rhythm is irregular.
• if the rhythm doesn’t vary or vaires <0.12 sec then it is considered regular

Question 14

Determine HR Ventricular

Answer 14

count the number of squares R to R
-divide by 1500 (for regular)
or
6 sec method (for irregular)
-count number of R to R and multiply by 10 for irregular beat

Question 15

Measure PR interval

Answer 15

-measure from the beginning of the P wave as it leaves baseline to the beginning of the QRS complex. Count the squares and multiply by 0.04 seconds

Question 16

Measure the QRS complex

Answer 16

-measure from the beginning of the QRS complex as it leaves the baseline until the end of the QRS complex when the ST segment begins. Count the squares and multiply by 0.04 seconds

Question 17

Sinus Rhythm

Answer 17

• impulse originates in the SA node
• normal sinus rhythm
• Components
• PQRST are all present
• P waves have the same appearance in front of each QRS
• rhythm-regular
• rate- atrial and ventricular rate are the same 60-100
• conduction- PRI 0.12-0.20 sec
• QRS <0.12

Question 18

Sinus Bradycardia

Answer 18

• components PQRST are all present
• P waves have the same appearance, in from of each QRS
• rhythm- regular
• rate- <60 beats/min
• conduction: normal
• patient response: normal for athletes, decreased CO for others
• TX: atropine if symptomatic

Question 19

Sinus Tachycardia

Answer 19

• components PQRST are all present
• p waves have the same appearance in from of each QRS
• rhythm- regular
• rate->100 beats/min
• conduction- normal
• patient response decrease CO
• TX- treat cause

Question 20

Atrial rhythms/premature atrial contraction

Answer 20

• components-PQRST present, same appearance in baseline rhythm, P wave abnormal or lost in PAC
• rhythm- irregular, R-R are not the same
• PAC occurs early, causing a short T-QRS length
• conduction-QRS <.12 sec, PRI measured on baseline rhythm

Question 21

Atrial Tachycardia

Answer 21

• components- QRST present, same appearance, P lost in the preceeding T, T may invert due to ischemia
• rhythm- regular
• Rate- 150-250
• conduction- unable to measure PRI, QRS normal
• patient response decrease CO
• Tx- beta-blockers, calcium channel blockers, digonxin