E1: Waves, Compleces, Intervals, HR

Question 1

What is the duration and amplitude of a large box on an EKG?

Answer 1

Duration: 0.2 seconds
Amplitude: 5mm

Question 2

What is the duration and amplitude of a small box on EKG?

Answer 2

Duration: 0.04 seconds
Amplitude: 1mm

Question 3

What does the P wave represent?

Answer 3

Depolarization of the RA and LA

Question 4

What is the normal duration of the QRS complex?

Answer 4

0.06-0.12 s

Question 5

What is aVr used to evaluate?

Answer 5

Views the base of the heart (atria and great vessels)

Question 6

What is aVL used to evaluate?

Answer 6

Views lateral wall of LV

Question 7

What is aVF used to evaluate?

Answer 7

Views inferior wall of LV

Question 8

What are the precordial leads used to evaluate?

Answer 8

Provides anterior and lateral views of the heart in a horizontal plane

Question 9

What are the anterior leads?

Answer 9

V1-4

Question 10

What are the lateral leads?

Answer 10

1, aVL, V5-6

Question 11

What are the inferior leads?

Answer 11

II, III, and aVF

Question 12

What is paroxysmal tachycardia?

Answer 12

A normal rate that suddenly accelerates to a rapid rate producing an irregularity in the rhythm

Question 13

What is a sinus dysrhythmia?

Answer 13

When the rate gradually increases during inspiration and decreases during expiration

Question 14

How does the 6 second interval method work to determine HR?

Answer 14

Count the number of QRS complexes found in a 6 second interval and multiply by 10

Question 15

What are the numbers that you need to memorize to utilize the rage box method of determining HR?

Answer 15

300,150, 100, 75, 60, 50

Question 16

How does the 1500 method work to calculate HR?

When can this method not be used?

Answer 16

Count the number of small squares between 2 consecutive R waves and divide that number by 1500
-Cannot be used with irregular rhythms

Question 17

What is the normal duration and amplitude of a P wave?

Answer 17

Duration: 0.06-0.1 seconds
Amplitude: 0.5- 2.5mm

Question 18

What do tall, rounded, or peaked P waves indicate?

Answer 18

Increased right atrial pressure and right atrial dilation

Question 19

What does an P wave with an amplitude of > 2.5 mm suggest?

Answer 19

Right atrial enlargement, called P pulmonalei

Question 20

What do wide, notched, or biphasic P waves represent?

Answer 20

Increased left atrial pressure and left atrial dilation

Question 21

What does a P wave with a width >0.1 indicate?

Answer 21

LAE, called P mitrale

Question 22

What lead are biphasic P waves normal?

Answer 22

V1

Question 23

What produced inverted P waves?

Answer 23

Retrograde depolarization of the atria, may immediately precede, occur during, or follow the QRS complex.
-Associated with dysrhythmias that originate from the AV junction

Question 24

What causes tall QRS complexes?

Answer 24

• Hypertrophy of one or both ventricles
• abnormal pacemaker
• Aberrantly conducted beat

Question 25

What causes low voltage QRS complexes?

Answer 25

• Obesity
• pericardial effusion
• Hypothryoidism

Question 26

What often causes wide-bizarre QRS complexes?

Answer 26

• Often result from IVCD

- may be a result of right or left BBB

Question 27

What causes aberrant conduction?

Answer 27

When electrical impulses reach the bundle branch while it is still refractory after conducting a previous electrical impulse

Question 28

How long is a normal PR interval?

Answer 28

0.12-0.2 seconds

Question 29

What causes a short PR interval?

Answer 29

When the impulse originates in the atria close to the AV junction or in the AV junction

Question 30

What causes long PR intervals?

Answer 30

When there is a delay in impulse conduction through the AV node
-1st degree AV block

Question 31

What happens in 3rd degree heart block?

Answer 31

The atria and ventricles are beating independently of each other

Question 32

What is the normal duration for QT interval?

Answer 32

0.36 - 0.44 seconds

Question 33

What is the difference between the PR interval and the PR segment?

Answer 33

The PR interval begins at the start of the P wave and ends at the beginning of the QRS complex.

The PR segment is the flat, iOS electric line between the end of the P wave and the start of the QRS complex

Question 34

In which lead is the P wave normally negative?

Which lead is the P wave normally Biphasic?

Answer 34

Negative in lead aVR.
Biphasic in lead V1

** positive in all other leads