Deck 17: Interpreting the Electrocardiogram

Question 1

What structure serves as the backup pacemaker for the heart?

A)atrioventricular (AV) node
B)sinoatrial node
C)bundle of His
D)Purkinje fibers

Answer 1

A

Question 2

Valvular defects in the heart can be detected with a 12-lead ECG.

Answer 2

False

Question 3

What parameter is measured on the vertical axis of the ECG paper?

A)time
B)voltage
C)cardiac contraction rate
D)blood flow

Answer 3

B

Question 4

The electrocardiogram (ECG) is primarily used to evaluate the patient with symptoms suggestive of acute myocardial disease.

Question 5

What is implied by an abnormally prolonged PR interval?

A)atrioventricular block
B)bundle-branch block
C)myocardial infarction
D)valvular detachment

Question 6

Which of the following axis placements represents right-axis deviation?

A)+60
B)+90
C)+120
D)+190

Question 7

What is the normal period of time for the PR interval?

A)not longer than 0.20 second
B)not longer than 0.30 second
C)not longer than 0.45 second
D)not longer than 0.50 second

Question 8

The QRS of an ECG falls on a dark vertical line of the ECG paper. Subsequent QRS complexes fall on every other dark line (10 mm apart). What is the ventricular rate?

A)300/min
B)200/min
C)150/min
D)100/min

Question 9

Why is the electrical impulse temporarily delayed at the atrioventricular (AV) node?

A)to allow complete emptying of the ventricles
B)to allow more sodium buildup in the myocardial cells
C)to allow better filling of the ventricles
D)to allow complete filling of the atria

Question 10

What structure normally paces the healthy heart?

A)atrioventricular (AV) node
B)sinoatrial (SA) node
C)bundle of His
D)Purkinje fibers

Question 11

Which of the following waves represents depolarization of the ventricles?

A)P wave
B)QRS wave
C)T wave
D)U wave

Question 12

What is suggested by inverted T waves on the ECG?

A)atrial enlargement
B)myocardial ischemia
C)ventricular hypertrophy
D)dextrocardia

Question 13

Which of the following waves represents repolarization of the ventricles?

A)P
B)QRS
C)T
D)U

Question 14

Which of the following ECG abnormalities is most life threatening?

A)narrow QRS complex
B)shortened PR interval
C)elevated ST segment
D)peak P waves

Question 15

What is the width of the normal QRS complex?

A)not wider than 1 mm
B)not wider than 3 mm
C)not wider than 5 mm
D)not wider than 7 mm

Question 16

What condition is often associated with right-axis deviation?

A)cor pulmonale
B)congestive heart failure (CHF)
C)mitral valve prolapse
D)left ventricular hypertrophy

Question 17

What term is used to define the ability of certain cardiac cells to depolarize without stimulation?

A)automaticity
B)polarization
C)contraction
D)repolarization

Question 18

Your patient has a normal ECG reading. What does this finding tell you about the patient's likelihood of having a myocardial infarction in the immediate future?

A)less than a 10% chance
B)less than a 30 % chance
C)less than 50% chance
D)no predictive value

Question 19

What is the normal maximum length of the P wave?

A)1 mm
B)3 mm
C)5 mm
D)7 mm

Question 20

At what part of the cardiac conduction system does the electrical impulse travel most rapidly?

A)bundle of His
B)bundle branches
C)intraatrial pathways
D)Purkinje fibers

Question 21

Which of the following medications is used to treat sinus bradycardia?

A)atropine
B)digitalis
C)propranolol
D)lidocaine

Question 22

Which of the following criteria applies to third-degree block?

A)There is no relationship between the P waves and the QRS complexes.
B)The PR interval becomes progressively longer.
C)The ventricular rate is twice that of the atrial rate.
D)The QRS complex is inverted compared to the P wave.

Question 23

On inspection of an ECG rhythm strip from an adult patient, you notice the following: regular sawtooth-like waves occurring at a rate of 280/min and a regular ventricular rhythm occurring at a rate of about 140/min. What is the most likely interpretation?

A)atrial fibrillation
B)atrial flutter
C)ventricular tachycardia
D)ventricular fibrillation

Question 24

Which of the following is NOT a common cause of ventricular tachycardia?

A)myocardial infarction
B)coronary artery disease
C)hypertensive heart disease
D)pericarditis

Question 25

An occasional premature ventricular complex (PVC) is not of major concern.

Question 26

Which of the following clinical conditions is not associated with tachycardia?

A)anxiety
B)hypoxemia
C)pain
D)hypothermia

Question 27

What is a possible serious complication associated with atrial fibrillation?

A)pulmonary edema
B)atrial thrombi
C)cardiac tamponade
D)cardiac standstill

Question 28

The ECG you are looking at has one P wave for every QRS complex and the PR interval is 0.30 second. What is your interpretation?

A)first-degree heart block
B)right-axis deviation
C)third-degree heart block
D)atrial hypertrophy

Question 29

Which of the following is NOT a common characteristic of a premature ventricular complex (PVC)?

A)no P wave prior to the QRS complex
B)widened QRS complex
C)bizarre QRS complex
D)narrow QRS

Question 30

For which of the following arrhythmias would an electronic pacemaker be indicated?

A)first-degree block
B)sinus tachycardia
C)third-degree block
D)ventricular fibrillation

Question 31

What medication is most useful for the treatment of premature ventricular contractions?

A)digoxin
B)atropine
C)lidocaine
D)digitalis

Question 32

Atrial flutter is considered to be a life-threatening arrhythmia.

Question 33

What type of medications may lead to first-degree heart block?

A)bronchodilators
B)corticosteroids
C) $\beta$ -blockers
D)xanthines

Question 34

Sources for the electrical impulse that triggers cardiac contraction that lie outside the sinoatrial node are referred to as ectopic foci.