Deck 10: Posttest

Question 1

An ECG machine's sensitivity must be calibrated so that a 1-mV electrical signal will produce a deflection measuring exactly _____-mm tall.

A) 0.5
B) 1
C) 5
D) 10

Answer 1

D
The ECG machine's sensitivity must be calibrated so that a 1-mV electrical signal will produce a deflection that measures exactly 10-mm tall. When properly calibrated, a small box is 1-mm high (i.e., 0.1 mV), and a large box, which is equal to five small boxes, is 5 mm high (i.e., 0.5 mV).

Question 2

The inferior surface of the left ventricle is supplied by the _____ coronary artery in most of the population.

A) left
B) right

Answer 2

B
A branch of the RCA supplies the inferior surface of the left ventricle in approximately 85% of individuals.

Question 3

_____ is a term used to describe the period of recovery that cells need after being discharged before they are able to respond to a stimulus.

A) Irritability
B) Polarization
C) Conductivity
D) Refractoriness

Answer 3

D
Refractoriness is a term used to describe the period of recovery that cells need after being discharged before they are able to respond to a stimulus.

Question 4

In an adult, the normal duration of the QRS complex is _____ seconds.

A) 0.12 to 0.20
B) 0.06 to 0.11
C) 0.04 to 0.14
D) 0.20 to 0.38

Question 5

Atrial fibrillation is characterized by _____.

A) an erratic, wavy baseline and irregular ventricular rhythm
B) "saw-tooth"- or "picket-fence"-shaped waveforms preceding each QRS
C) one P wave before each QRS and a regular ventricular rate of 60 to 100 beats/min
D) P waves occurring before, during, or after the QRS complex; when seen, they are inverted

Question 6

Two conditions must exist to suspect bundle branch block. First, the QRS complex must have an abnormal duration (0.12 second or more in width), and second _____.

A) an RSR' complex must be seen in leads V1-V6
B) a QS pattern must be seen in leads I, II, and III
C) a slurred upstroke of the QRS complex must exist
D) the QRS complex must arise as the result of supraventricular activity

Question 7

Which of the following correctly describes multifocal atrial tachycardia?

A) The atrial rhythm is regular.
B) The ventricular rhythm is irregular.
C) The atrial and ventricular rhythms are regular.
D) The atrial and ventricular rhythms are irregular.

Question 8

Which of the following are chest leads?

A) Leads I and aVL
B) Leads I, II, and III
C) Leads V1, V2, V3, V4, V5, V6
D) Leads I, II, III, aVR, aVL, and aVF

Question 9

Where is the positive electrode placed in lead III?

A) Right arm
B) Left arm
C) Left leg or foot
D) Right leg or foot

Question 10

In a junctional rhythm viewed in lead II, where is the location of the P wave on the ECG if ventricular depolarization precedes atrial depolarization?

A) Before the QRS complex
B) During the QRS complex
C) After the QRS complex

Question 11

Anterior wall myocardial infarctions are most often a result of an occlusion of a branch of the _____ coronary artery.

A) left
B) right

Question 12

Which of the following correctly reflects the ECG indicators of ischemia?

A) Pathologic Q waves, ST-segment elevation
B) ST-segment elevation, T-wave inversion
C) ST-segment depression, T-wave inversion
D) Pathologic Q waves, ST-segment depression

Question 13

On an ECG, what is the first negative deflection seen after the P wave?

A) Q wave
B) R wave
C) S wave
D) T wave

Question 14

The _____ originate from small mounds of myocardium called papillary muscles and serve as anchors to prevent the cusps of the AV valves from inverting into the atria.

A) Purkinje fibers
B) coronary sinuses
C) coronary arteries
D) chordae tendineae

Question 15

Which of the following leads are anatomically contiguous?

A) II, V2
B) II, III, V3
C) I, V3, V4
D) V2, V3, V4

Question 16

Signs and symptoms experienced during a tachydysrhythmia are usually primarily related to _____.

A) atrial irritability
B) vasoconstriction
C) slowed conduction through the AV node
D) decreased ventricular filling time and stroke volume

Question 17

Which side of the heart is a high-pressure system that pumps arterial blood to the systemic circulation?

A) Left
B) Right

Question 18

The myocardium is thickest in the ____.

A) left atrium
B) right atrium
C) left ventricle
D) right ventricle

Question 19

The left atrium receives blood from the _____.

A) aorta
B) pulmonary veins
C) pulmonary arteries
D) inferior vena cava

Question 20

A delta wave is an ECG characteristic associated with which of the following dysrhythmias?

A) Junctional rhythm
B) AV nodal reentrant tachycardia (AVNRT)
C) Wolff-Parkinson-White (WPW) syndrome
D) Accelerated idioventricular rhythm (AIVR)

Question 21

Sometimes, when a premature atrial complex (PAC) occurs very prematurely and close to the T wave of the preceding beat, only a P wave may be seen with no QRS after it (appearing as a pause). This type of PAC is termed a(n) _____ PAC.

Question 22

An accessory pathway that has one end attached to normal conductive tissue is called a(n) __________.

Question 23

A Q wave, if present, is always a negative waveform.

Question 24

Which of the following are chest leads?

A) Leads I, II, and III
B) Leads I and aVL
C) Leads V1, V2, V3, V4, V5, and V6
D) Leads I, II, III, aVR, aVL, and aVF

Question 25

A beat originating from the AV junction that appears later than the next expected sinus beat is called a(n) _______________.

Question 26

When reviewing a 12-lead ECG, intervals and duration are usually expressed in _____.

Question 27

Lead III views the _____ wall of the left ventricle.

A) septal
B) inferior
C) posterior
D) lateral

Question 28

The first segment of the left coronary artery is the _____ artery.

A) circumflex
B) right coronary
C) left main coronary
D) left anterior descending

Question 29

In the limb leads, the ST segment is normally isoelectric.

Question 30

If the AV junction paces the heart, the electrical impulse must travel in a backward direction to activate the atria. This is called _____ conduction.

Question 31

A(n) __________ is a vertical line on the ECG that indicates the pacemaker has discharged.

Question 32

Myocardial ischemia delays the process of repolarization; therefore the ECG changes characteristic of ischemia include _____.

A) widening of the QRS complex
B) prolongation of the PR interval
C) changes in the ST segment and T wave
D) changes in the QRS complex and ST segment

Question 33

How are frequent PACs usually managed?

A) Defibrillation
B) Synchronized cardioversion
C) Correcting the underlying cause
D) Administration of medications such as atropine or epinephrine

Question 34

The axes of leads I, II, and III form an equilateral triangle with the heart at the center (Einthoven's triangle). If the augmented limb leads are added to this configuration and the axes of the six leads moved in a way in which they bisect each other, the result is the _______________.

Question 35

The anterior surface of the heart consists primarily of the _____.

A) left atrium
B) right atrium
C) left ventricle
D) right ventricle

Question 36

A(n) __________ occurs as a result of an electrical impulse from a supraventricular site (such as the SA node) discharging at the same time as an ectopic site in the ventricles.

Question 37

Tall, peaked T waves observed on the ECG are most commonly seen in patients with _____.

A) hypokalemia
B) hyponatremia
C) hyperkalemia
D) hypernatremia

Question 38

The term acute coronary syndromes refers to patients presenting with ischemic chest pain.

Question 39

A _____ bundle branch block produces a QS pattern in lead V?.

Question 40

A QRS measuring 0.10 to 0.12 second is called a(n) _____ right or left bundle branch block.

Question 41

Describe the appearance of a pathologic Q wave.

Question 42

In most ECG leads, a normal Q wave is less than 0.04 second in duration and less than one third of the amplitude of the R wave in that lead.

Question 43

Explain the difference between a PVC and a ventricular escape beat.

Question 44

A delay or block that occurs in one of the bundle branches affects ventricular depolarization.

Question 45

Cardiac output is the amount of blood pumped into the aorta each minute by the heart.

Question 46

Proper positioning of the electrodes for leads I, II, and III requires placement on the patient's torso.

Question 47

The point where the QRS complex and ST segment meet is called the ST junction or the J point.

Question 48

A macroreentrant circuit is one that involves a small area of heart tissue, usually a few centimeters or less.

Question 49

Depolarization is the same as contraction.

Question 50

The six limb leads view the heart in the frontal plane as if the body were flat.

Question 51

The term ectopic refers to an extra muscle bundle consisting of working myocardial tissue that forms a connection between the atria and ventricles outside the normal conduction system.

Question 52

The electrocardiogram (ECG) is a reflection of the heart's mechanical activity.

Question 53

What is a biphasic waveform?

Question 54

Explain the meaning of the letters in aVR, aVL, and aVF.

Question 55

When is the term intraventricular conduction delay used?

Question 56

Explain the benefits of a dual-chamber pacemaker.

Question 57

Your patient has a VVI pacemaker. Briefly explain the meaning of each of these letters.

Question 58

Leads V?R, V?R, and V?R are used to view the posterior wall of the left ventricle.

Question 59

Individuals with preexcitation syndrome are predisposed to tachydysrhythmias.

Question 60

List five signs or symptoms of decreased cardiac output.

Question 61

Indicate the heart surface viewed by each of the following:

Question 62

Complete the following:

Question 63

Indicate the inherent rates for each of the following pacemaker sites: