Deck 19: The Electrocardiogram and Cardiac Arrhythmias In Adults

Question 1

How long does it normally take for the ventricles to depolarize?

A)0.08 to 0.1 second
B)0.1 to 0.2 second
C)0.25 to 0.3 second
D)0.3 to 0.4 second

Answer 1

0.08 to 0.1 second

Question 2

Which of the following are features of the PR interval?
I.It is measured from the beginning of the P wave to the first ventricular deflection.
II.It is measured from the beginning of the P wave to the S wave.
III.The normal PR interval is between 0.12 and 0.20 second.
IV.The PR interval can be shorter for fast heart rates than for slow heart rates.

A) I, II
B) I, III, IV
C) I, II, III, IV
D) II, III

Answer 2

I, III, IV

Question 3

Why is a prolonged QT interval associated with life-threatening heart rhythm disturbances?

A) It is associated with a longer vulnerable period.
B) Calcium influx is the greatest during this period.
C) The SA node becomes refractory to the normal depolarization.
D) This period is refractory to AV depolarization.

Answer 3

It is associated with a longer vulnerable period.

Question 4

What is the normal MCV angle?

A) +30 degrees
B) +60 degrees
C) +90 degrees
D) -30 degrees

Question 5

Which of the following limb leads are unipolar?
I.Leads aVR, aVL, aVF
II.Leads V?, V?, V?
III.Leads V?, V?, V?
IV.Leads I, II, III

A) I
B) II, III
C) IV
D) I, IV

Question 6

Atrial depolarization is represented by which of the following waves in the ECG?

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

Question 7

Which of the following conditions are detected by the ECG?
I.Abnormal heart rhythms
II.Conduction problems
III.Location of damaged heart muscle
IV.Force of contraction

A) I, II, III
B) III, IV
C) I, II, III, IV
D) II, III

Question 8

When the heart rate is 150 beats/min, the interval between two QRS complexes in the typical 25 mm/sec ECG is?

A) 1 large square
B) 2 large squares
C) 3 large squares
D) 4 large squares

Question 9

The normal MCV is parallel to which of the following leads?

A) I
B) II
C) III
D) aV_F

Question 10

In which direction does ventricular depolarization normally occur?
I.Leftward
II.Downward
III.Anterior
IV.Posterior

A) I, II
B) I, II, IV
C) I, II, III, IV
D) I, II, III

Question 11

Which of the following are characteristics of the normal ST segment?
I.The ST segment is normally flat, lying on the baseline.
II.This segment may be elevated as much as 2 mm above the baseline.
III.This segment may be depressed as much as 2 mm below the baseline.
IV.An ST segment that becomes depressed more than 0.5 mm is abnormal.

A) I, II
B) III, IV
C) I, II, IV
D) I, II, III

Question 12

A 60-year-old man with COPD is chronically hypoxemic and hypercapnic.A standard electrocardiogram (ECG) reveals a strongly negative QRS complex in lead I and a more positive than negative QRS complex in aV_F.What explains this finding?

A) Normal axis deviation
B) Right axis deviation
C) Left axis deviation
D) Isoelectric axis deviation

Question 13

Ventricular depolarization is represented by which of the following waves in the ECG?

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

Question 14

Ventricular repolarization is represented by which of the following waves in the ECG?

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

Question 15

Which of the following findings are consistent with a left axis deviation?
I.A positive QRS in lead I
II.A positive QRS in lead II
III.A negative QRS in lead aVF
IV.A positive QRS in lead aVR

A) I, II
B) I, III
C) II, IV
D) II, III

Question 16

Which of the following is the only parameter that the ECG measures?

A) Electrical events
B) Contraction force
C) Heart muscle mass
D) Heart position

Question 17

An abnormally elevated ST segment is indicative of which of the following?

A) Myocardial ischemia
B) Myocardial tissue injury
C) Myocardial abnormal contraction
D) Myocardial ectopy

Question 18

Which of the following leads allow the cardiac vector to be located within the normal 90-degree quadrant? Which two leads are best utilized to determine the direction of the cardiac vector?
I.I
II.II
III.aV_L
IV.aV_F

A) I, II
B) I, IV
C) II, IV
D) II, III

Question 19

What is the normal variation between the shortest and longest R-R interval in a regular sinus rhythm?

A) Less than 0.4 second
B) Less than 0.3 second
C) Less than 0.16 second
D) Less than 0.08 second

Question 20

In cases of extreme obesity, where may the MCV be located?

A) +30 degrees
B) +60 degrees
C) +90 degrees
D) -30 degrees

Question 21

In the palpation of a pulse of a patient with atrial flutter with an atrial rate of 300, what is the expected pulse rate?

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

Question 22

What is the heart rate associated with a junctional escape rhythm?

A) 100 to 150 beats/min
B) 80 to 100 beats/min
C) 60 to 80 beats/min
D) 40 to 60 beats/min

Question 23

In patients with no underlying ischemic heart disease, treatment of PSVT involves which of the following?
I.Epinephrine
II.Vagal parasympathetic stimulation
III.Intravenous calcium channel blockers
IV.Intravenous adenosine administration

A) I, II, III
B) I, III
C) II, III, IV
D) I, II, III, IV

Question 24

When auscultating heart sounds of a patient, the clinician reports normal beats followed by few abnormal beats.An ECG reveals the following tracing.What is this consistent with?

A) Premature ventricular contractions
B) Escape rhythm
C) Ventricular fibrillation
D) Second-degree AV block.

Question 25

What is the heart rate associated with atrial flutter?

A) 100 to 150 beats/min
B) 200 to 350 beats/min
C) 350 to 400 beats/min
D) 400 to 450 beats/min

Question 26

The PR intervals are constant, but with various conduction ratios, in which type of AV block?

A) First-degree
B) Type I second-degree
C) Type II second-degree
D) Third-degree

Question 27

An ECG reveals that all sinus nodal impulses are conducted to the ventricles, but the PR interval is greater than 0.2 second and all QRS complexes have normal configurations.What is the best interpretation of this ECG?

A) Normal
B) First-degree AV block
C) Second-degree AV block
D) Third-degree AV block

Question 28

The PR intervals gradually lengthen until a QRS complex fails to appear after the P wave in which type of AV block?

A) First-degree
B) Type I second-degree
C) Type II second-degree
D) Third-degree

Question 29

Assessment of a patient who is unresponsive reveals the absence of a pulse.Which of the following abnormal rhythms is most consistent with this finding?

A) Auricular fibrillation
B) Third-degree AV block
C) Ventricular tachycardia
D) PSVT

Question 30

No relationship exists between P waves and QRS complexes in which type of AV block?

A) First-degree
B) Type I second-degree
C) Type II second-degree
D) Third-degree

Question 31

What is the most lethal of all cardiac arrhythmias?

A) SVT
B) VF
C) VT
D) Multifocal PVCs

Question 32

In nonathletes, rates of 30 to 45 beats/min often generate which of the following symptoms?
I.Hypotension
II.Sweating
III.Weakness
IV.Dizziness

A) I, II, III
B) I, III
C) II, IV
D) I, II, III, IV

Question 33

Which of the following conditions are associated with sinus tachycardia?
I.Fever
II.Anxiety
III.Pain
IV.Smoking

A) I, II, III
B) I, III
C) II, IV
D) I, II, III, IV

Question 34

Which of the following are the most common characteristics of PAC?
I.PACs may originate from a single ectopic focus or from multiple ectopic foci in the atria.
II.Ventricular QRS complexes are normal.
III.Ventricular QRS complexes are abnormally wide.
IV.QRS complexes are irregularly spaced.

A) I, II, III
B) I, III
C) I, II, IV
D) I, II, III, IV

Question 35

What is the most serious potential risk for patients with VT?

A) Hypotension
B) Progression to VF
C) Bradycardia
D) Tachycardia

Question 36

In healthy people with healthy hearts, PVCs occur occasionally after the use of which of the following substances?
I.Alcohol
II.Caffeine
III.Tobacco
IV.Chocolate

A) I, II, III
B) I, III
C) II, III, IV
D) I, II, III, IV

Question 37

Inadequate filling time coupled with the loss of the atrial kick is associated with which of the following physical findings?

A) Hypotension
B) Pulse deficit
C) Bounding pulse
D) Ventricular beat cannot be heard with the stethoscope.

Question 38

Which of the following are characteristics of PVCs?
I.A full compensatory pause occurs after the PVC.
II.They generate T waves of opposite polarity from normal.
III.The QRS complex is wide.
IV.P waves are unrelated to the PVC.

A) I, II, III
B) I, III
C) II, III, IV
D) I, II, III, IV

Question 39

Which of the following conditions are associated with sinus bradycardia?
I.Airway suctioning
II.Valsalva's maneuver
III.Vomiting
IV.Coughing

A) I, II, III
B) I, III
C) II, IV
D) I, II, III, IV

Question 40

What is considered the hallmark of atrial fibrillation?

A) Regular ventricular rhythm accompanied by f waves
B) Totally irregular ventricular rhythm accompanied by flutter waves
C) Totally irregular auricular rhythm accompanied by normal QRS waves
D) Totally irregular ventricular rhythm accompanied by f waves