Question 1

Lead aVL views the _____.
A) interatrial septum
B) lateral wall of the left ventricle
C) inferior wall of the left ventricle
D) anterior wall of the right ventricle

Accepted Answer

Lead aVL views the lateral wall of the left ventricle.

Question 2

Which of the following leads should be used to view the right ventricle? A) V₃ B) V₇ C) V₄R D) V₆

Accepted Answer

Leads V₁R to V₆R are used to view the right ventricle.

Question 3

Where should the positive electrode for lead V₁ be positioned? A) Right side of the sternum,fourth intercostal space B) Left midaxillary line at the same level as V₄ C) Left side of the sternum,fourth intercostal space D) Left anterior axillary line at the same level as V₄

Accepted Answer

The positive electrode for lead V₁ is positioned on the right side of the sternum,fourth intercostal space.

Question 4

Which of the following ECG changes is one of the earliest to occur during an ST-elevation infarction,but may have resolved by the time the patient seeks medical assistance?
A) Pathologic Q waves
B) Hyperacute T waves
C) Horizontal ST-segments
D) Lengthening of the QT interval

Accepted Answer

Hyperacute (i.e.,tall)T waves are sometimes called tombstone T waves and typically measure more than 50% of the preceding R wave.In addition to an increase in height,the T wave becomes more symmetric and may become pointed.These changes are often not recorded on the ECG because they have typically resolved by the time the patient seeks medical assistance.

Question 5

Lead V₃ views the _____ wall of the left ventricle. A) lateral B) anterior C) posterior D) inferior

Accepted Answer

Lead V₃ views the anterior of the left ventricle.

Question 6

Lead V₅views the _____ wall of the left ventricle. A) lateral B) anterior C) posterior D) inferior

Accepted Answer

Lead V₅ views the lateral wall of the left ventricle.

Question 7

An abnormal (i.e.,pathologic)Q wave indicates the presence of dead myocardial tissue.

Accepted Answer

An abnormal (i.e.,pathologic)Q wave is more than 0.04 seconds in duration or more than one third the height of the following R wave in that lead.Myocardial infarction is one possible cause of abnormal Q waves.In the early hours of infarction,an abnormal Q wave may not have developed to its full width or amplitude.Therefore a single ECG tracing might not identify an abnormal Q wave.In a patient with a suspected myocardial infarction,be sure to look at Q waves closely.Even if the initial ECG tracings do not show Q waves that are more than 0.04 seconds in duration or equal to or more than one third of the amplitude of the QRS complex,pathology must be considered if the Q waves become wider or deeper in each subsequent tracing.

Question 8

When you read a 12-lead ECG from left to right,the ECG tracing is continuous.

Accepted Answer

When viewing a 12-lead ECG,leads that line up vertically are simultaneous recordings of the same beat.When you read the 12-lead ECG from left to right,the ECG tracing is continuous.As you switch from one lead to the next,it is still continuous.

Question 9

The inferior wall of the left ventricle is supplied by the _____ coronary artery in most of the population.
A) left
B) right

Accepted Answer

The inferior wall of the left ventricle is supplied by the right coronary artery in most people.If an ECG shows changes in leads II,III,and aVF,the inferior wall is affected,and it is reasonable to suppose that these ECG changes are due to partial or complete blockage of the right coronary artery.

Question 10

A standard 12-lead ECG provides views of the heart in _____.
A) the frontal plane only
B) the sagittal plane only
C) the horizontal plane only
D) both the frontal and the horizontal planes

Accepted Answer

A standard 12-lead ECG provides views of the heart in both the frontal and horizontal planes and views the surfaces of the left ventricle from 12 different angles.

Question 11

Anterior or lateral wall myocardial infarctions are most often a result of an occlusion of the _____ coronary artery.
A) left
B) right

Accepted Answer

Anterior or lateral wall myocardial infarctions are most often a result of an occlusion of the left coronary artery.

Question 12

Poor R-wave progression is a phrase used to describe R waves that decrease in size from V₁ to V₄.This is often seen in an _____ infarction. A) anteroseptal B) anterolateral C) inferolateral D) inferoposterior

Accepted Answer

Poor R-wave progression is a phrase used to describe R waves that decrease in size from V₁ to V₄.This is often seen in an anteroseptal infarction,but may be a normal variant in young persons,particularly in young women.Other causes of poor R-wave progression include left bundle branch block,left ventricular hypertrophy,and severe chronic obstructive pulmonary disease (particularly emphysema).

Question 13

Placement of right chest leads is identical to the standard chest leads except on the right side of the chest.

Accepted Answer

Placement of the right chest leads is identical to the standard chest leads except on the right side of the chest where the leads are placed in a mirror image position. Specifically, lead V1 is placed in the 4th intercostal space just to the right of the sternum, and lead V2 is placed in the 4th intercostal space just to the left of the sternum.

Question 14

Which leads look at adjoining tissue in the inferior region of the left ventricle? A) I,aVL B) V₁,V₂ C) V₃,V₄,V₅ D) II,III,aVF

Accepted Answer

Leads II,III,and aVF view adjoining tissue in the inferior region of the left ventricle.

Question 15

Lead V₁ views the _____. A) septum B) inferior wall of the left ventricle C) lateral wall of the right ventricle D) anterior wall of the right ventricle

Accepted Answer

Leads V₁and V₂ view the septum.

Question 16

Lead II views the _____ wall of the left ventricle.
A) anterior
B) inferior
C) septal
D) lateral

Accepted Answer

Lead II views the inferior wall of the left ventricle.

Question 17

Which leads face the septum? A) II,aVF B) V₁,V₂ C) V₅,V₆ D) I,aVL

Accepted Answer

Leads V₁ and V₂face the septum.

Question 18

The chest leads are the only unipolar leads in the standard 12-lead ECG.

Accepted Answer

The augmented voltage leads and the chest leads are unipolar leads.

Question 19

Where should the positive electrode for lead V₅ be positioned? A) Right side of the sternum,fourth intercostal space B) Left midaxillary line at the same level as V₄ C) Left side of the sternum,fourth intercostal space D) Left anterior axillary line at the same level as V₄

Accepted Answer

The positive electrode for lead V₅ is positioned at the left anterior axillary line at the same level as V₄.

Question 20

Which leads look at adjoining tissue in the anterior region of the left ventricle? A) II,III,aVF B) V₂,V₃,V₄ C) I,aVL,V₅ D) aVR,aVL,aVF

Accepted Answer

Leads V₂,V₃,and V₄ look at adjoining tissue in the anterior region of the left ventricle.

Quiz 9: Introduction to the 12-Lead ECG

Lead aVL views the _____.

Which of the following leads should be used to view the right ventricle?

Where should the positive electrode for lead V1 be positioned?

Which of the following ECG changes is one of the earliest to occur during an ST-elevation infarction,but may have resolved by the time the patient seeks medical assistance?

Lead V3 views the _____ wall of the left ventricle.

Lead V5views the _____ wall of the left ventricle.

An abnormal (i.e.,pathologic)Q wave indicates the presence of dead myocardial tissue.

When you read a 12-lead ECG from left to right,the ECG tracing is continuous.

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

A standard 12-lead ECG provides views of the heart in _____.

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

Poor R-wave progression is a phrase used to describe R waves that decrease in size from V1 to V4.This is often seen in an _____ infarction.

Placement of right chest leads is identical to the standard chest leads except on the right side of the chest.

Which leads look at adjoining tissue in the inferior region of the left ventricle?

Lead V1 views the _____.

Lead II views the _____ wall of the left ventricle.

Which leads face the septum?

The chest leads are the only unipolar leads in the standard 12-lead ECG.

Where should the positive electrode for lead V5 be positioned?

Which leads look at adjoining tissue in the anterior region of the left ventricle?

Where should the positive electrode for lead V₁ be positioned?

Lead V₃ views the _____ wall of the left ventricle.

Lead V₅views the _____ wall of the left ventricle.

Poor R-wave progression is a phrase used to describe R waves that decrease in size from V₁ to V₄.This is often seen in an _____ infarction.

Lead V₁ views the _____.

Where should the positive electrode for lead V₅ be positioned?