Deck 11: Interpretation of the Electrocardiogram

Question 1

What does the QRS complex represent?

A) Depolarization of the atria
B) Repolarization of the atria
C) Depolarization of the ventricles
D) Repolarization of the ventricles

Answer 1

Depolarization of the ventricles

Question 2

What is represented by the P wave on the ECG tracing?

A) Repolarization of the atria
B) Depolarization of the atria
C) Repolarization of the ventricles
D) Depolarization of the ventricles

Answer 2

Depolarization of the atria

Question 3

Which chamber is responsible for pumping blood into the pulmonary circulation?

A) Left atrium
B) Left ventricle
C) Right atrium
D) Right ventricle

Answer 3

Right ventricle

Question 4

What is the upper limit in height of the normal P wave?

A) 1 mm
B) 2.5 mm
C) 3.5 mm
D) 5 mm

Question 5

Which of the following physiologic effects is associated with myocardial infarction?

A) Arterial hypertension
B) Increased cardiac output
C) Good blood flow to the brain
D) Backup of blood into the lungs

Question 6

What is the ventricular heart rate when the AV node paces the heart?

A) 20 to 40 beats/min
B) 40 to 60 beats/min
C) 60 to 80 beats/min
D) 80 to 100 beats/min

Question 7

Which chamber of the heart initially receives deoxygenated blood from the vena cava?

A) Left atrium
B) Left ventricle
C) Right atrium
D) Right ventricle

Question 8

At what speed does the paper travel through the ECG machine?

A) 25 mm/s
B) 30 mm/s
C) 40 mm/s
D) 50 mm/s

Question 9

Why is the electrical signal delayed slightly at the AV node?
1) To allow better filling of the ventricles
2) To protect the ventricles against excessively rapid atrial rates
3) To provide time for atrial contraction prior to ventricular systole
4) To prevent premature atrial beats from reaching the ventricles

A)1 and 3
B)2 and4
C)1 and 2
D)2, 3, and 4

Question 10

Why is it important for a respiratory therapist (RT) to be able to identify cardiac dysrhythmias?

A) It is likely that the RT will observe the onset of the initial event.
B) The RT is primarily responsible for management of the dysrhythmia.
C) The RT must be able to confirm the physician's initial diagnosis.
D) RTs are always the first responders for complaints of a cardiac nature.

Question 11

What term applies to any heartbeat that originates outside the SA node?

A) Ectopic impulse
B) Aberrant impulse
C) Eccentric impulse
D) Recurrent impulse

Question 12

Where does the normal electrical impulse originate for each heartbeat?

A) Atrioventricular (AV) node
B) Sinoatrial (SA) node
C) Bundle of His
D) Right bundle branch

Question 13

Which of the following are associated with the onset of dysrhythmias?
1) Hypoxia
2) Electrolyte imbalances
3) Sympathetic stimulation
4) Pulmonary hypertension

A)1 and 2
B)3 and 4
C)2, 3, and 4
D)1, 2, and 3

Question 14

The normal QRS complex does not exceed what time on the horizontal axis?

A) 0.05 s
B) 0.10 s
C) 0.5 s
D) 1 s

Question 15

How much time is represented on the horizontal axis of the ECG paper by five large boxes?

A) 0.5 s
B) 1 s
C) 3 s
D) 5 s

Question 16

Why is an ECG tracing so useful?

A) It reflects the heart's pumping ability.
B) It can identify structural abnormalities in the heart.
C) It can be used to diagnose malfunctioning valves.
D) It can aid in the diagnosis of cardiac tissue ischemia.

Question 17

What term describes the sudden loss of the negative charge inside the myocardial cells?

A) Repolarization
B) Depolarization
C) Automaticity
D) Conductivity

Question 18

What term describes heart cells that have the ability to spontaneously depolarize?

A) Systole
B) Purkinje
C) Automaticity
D) Myocardiocity

Question 19

What is the normal range for the PR interval?

A) 0.05 to 0.1 s
B) 0.12 to 0.2 s
C) 0.2 to 0.35 s
D) 0.25 to 0.5 s

Question 20

Which chamber normally has the largest muscle mass?

A) Left atrium
B) Left ventricle
C) Right atrium
D) Right ventricle

Question 21

Which of the following is a hallmark of a premature ventricular contraction (PVC)?

A) The QRS complex is early but normal in appearance.
B) The QRS complex is wider than normal.
C) There is a P wave in front of the QRS complex.
D) The T wave moves in the same direction as the QRS complex.

Question 22

A patient complaining of chest pain that has not been relieved by nitroglycerin should be treated with all of the following except:

A) oxygen therapy.
B) thrombolytic therapy.
C) stress testing.
D) surgical intervention.

Question 23

What part of the heart is best viewed by the chest leads V₅ and V₆?

A) Left atrium
B) Right atrium
C) Left ventricle
D) Right ventricle

Question 24

What is considered to be the normal position of the axis in a healthy patient's heart?

A) 0 to -90 degrees
B) 0 to 90 degrees
C) 60 to 120 degrees
D) 120 to 180 degrees

Question 25

What is indicated by high-voltage R waves in the QRS complex?

A) Axis deviation
B) Atrial enlargement
C) Myocardial ischemia
D) Ventricular enlargement

Question 26

In the terminology for three of the limb leads-aV_R, aV_L, and aV_F-what does the letter "A" stand for?

A) Atrial
B) Assisted
C) Ambient
D) Augmented

Question 27

What dysrhythmia often follows sustained ventricular tachycardia?

A) Heart block
B) Atrial fibrillation
C) Elevated ST segments
D) Ventricular fibrillation

Question 28

Which of the following is a characteristic of third-degree heart block?

A) There is a lengthening PR interval.
B) There is often a 2:1 ratio between P waves and QRS complexes.
C) The atrial rate is the same as the ventricular rate.
D) There is no relationship between the P waves and the QRS complexes.

Question 29

What problem is indicated by elevation of the ST segment?

A) Heart block
B) Myocardial ischemia
C) Elevation of serum potassium
D) Depletion of serum potassium

Question 30

Which of the following are common causes of tachycardia?
1) Pain
2) Fever
3) Hypoxemia
4) Hypothyroidism

A)1 and 3
B)2 and 4
C)1, 2, and 3
D)2, 3, and 4

Question 31

Which of the following would describe the ECG of a patient with atrial fibrillation?

A) Regular ventricular response
B) Large bizarre QRS complexes
C) Chaotic baseline between QRS complexes
D) No identifiable QRS complexes

Question 32

What axis change is common in patients with chronic pulmonary hypertension?

A) Left axis deviation
B) Right axis deviation
C) Inverted axis deviation
D) Extreme left axis deviation

Question 33

What dysrhythmia is characterized by a sawtooth pattern of waves between normal QRS complexes on the ECG tracing?

A) Atrial flutter
B) Atrial fibrillation
C) Ventricular flutter
D) Ventricular fibrillation

Question 34

Which of the following dysrhythmias is associated with the lowest cardiac output?

A) AV block
B) Atrial fibrillation
C) Ventricular flutter
D) Ventricular fibrillation

Question 35

A patient who has atrial fibrillation is at risk for which of the following pulmonary conditions?

A) Chronic obstructive pulmonary disease (COPD)
B) Pneumothorax
C) Pleural effusion
D) Pulmonary emboli

Question 36

What is the normal progression of abnormalities seen on the ECG for a patient who is having a myocardial infarction?

A) ST elevation followed by large Q waves
B) ST depression followed by large Q waves
C) Large Q waves, ST elevation, followed by ST depression
D) ST depression, large Q waves, and then ST segment elevation

Question 37

What is the heart rate if the RR interval is five large boxes apart?

A) 40 beats/min
B) 60 beats/min
C) 90 beats/min
D) 120 beats/min

Question 38

Which of the following dysrhythmias represents a dissociation of the mechanical and electrical activities of the heart?

A) Asystole
B) AV block
C) Bradycardia
D) Pulseless electrical activity (PEA)

Question 39

What is the upper limit of normal for the width of a normal Q wave?

A) 0.08 s
B) 0.04 s
C) 1.2 s
D) 1.4 s

Question 40

Which of the following would be a typical ECG finding in a patient with emphysema?

A) Reduced voltage in the limb leads
B) Left axis deviation
C) Smaller-than-normal P waves
D) Prominent QRS complexes, particularly in leads V₅ and V₆