Question 1

What happens when one or both of the ventricular pathways are not functioning properly due to damage or a delay from cardiac disease, drugs, or other conditions?
A)A bundle branch block occurs
B)The patient never experiences PVCs
C)An idioventricular rhythm occurs
D)A second degree AV heart block, type I occurs

Accepted Answer

When one or both of the ventricular pathways are not functioning properly due to damage or delay, a bundle branch block can occur. This is because these pathways are part of the bundle branches in the heart, and when they are damaged, the electrical impulses that control the heart's rhythm can be disrupted, causing the bundle branches to not work correctly. This can result in a delay or blockage in the transmission of electrical signals, leading to a bundle branch block.

Question 2

A patient's dysrhythmia originates from above the ventricles and you notice QRS complexes on the ECG tracing measuring 0.12 second or greater. What could be the cause of this abnormal morphology?
A)Supraventricular tachycardia
B)Third-degree AV block
C)Bundle branch block
D)Atrial fibrillation

Accepted Answer

Bundle branch block is the cause of the abnormal morphology described. When there is a bundle branch block, the electrical impulse is delayed or blocked within the bundle branches, leading to a widening of the QRS complex on the ECG, which is indicated by a duration of 0.12 second or greater. This condition affects the ventricles' ability to contract simultaneously, causing the abnormal QRS morphology.

Question 3

Which of the following statements about bundle branch block is true?
A)Bundle branch block is a life-threatening condition.
B)Bundle branch block overrides the patient's underlying heart rhythm.
C)Any sinus, atrial, or junctional rhythm can be affected by bundle branch block.
D)If the patient has a bundle branch block, no P wave will be seen on the ECG tracing.

Accepted Answer

Bundle branch block can affect any sinus, atrial, or junctional rhythm. It is not necessarily life-threatening and does not override the patient's underlying heart rhythm. P waves can still be seen on the ECG tracing, but QRS complexes may appear widened or distorted, indicating the blockage or delay in the electrical signal traveling through the bundle branches.

Question 4

Which of the following is a characteristic of left bundle branch block?
A)The right ventricle depolarizes normally, but conduction through the left ventricle is slowed.
B)The left ventricle depolarizes normally, but the impulse is not spread to the right ventricle.
C)Neither ventricle depolarizes normally because the impulse is not conducted through the left bundle branch.
D)Neither ventricle depolarizes normally because the impulse is not conducted through the right bundle branch.

Accepted Answer

In left bundle branch block (LBBB), the electrical impulse that normally travels down the left bundle branch is delayed or blocked. This means that the right ventricle depolarizes normally through the right bundle branch, but the conduction through the left ventricle is slowed, leading to a delay in the depolarization of the left ventricle.

Question 5

Bundle branch block rhythm is similar to a sinus rhythm but has what distinguishing characteristic?
A)PR interval greater than 0.20 seconds
B)QRS duration less than 0.12 seconds
C)PR interval less than 0.12 seconds
D)QRS duration greater than 0.12 seconds

Accepted Answer

Bundle branch block rhythm has a QRS duration greater than 0.12 seconds due to delayed ventricular activation caused by blockage in one of the bundle branches. The PR interval is typically within normal limits.

Question 6

What rhythm is shown in this ECG tracing? 
A)Junctional escape rhythm
B)Sinus dysrhythmia with bundle branch block
C)Sinus bradycardia
D)Sinus bradycardia with bundle branch block

Accepted Answer

The answer of What rhythm is shown in this ECG...

Question 7

What measurement on the ECG tracing represents how long it takes for the current to travel through the ventricular myocardial tissue?
A)PR interval
B)QRS duration
C)P-P interval
D)R-R interval

Accepted Answer

The QRS duration represents the time it takes for the electrical impulse to travel through the ventricular myocardial tissue. The PR interval represents the time from the start of atrial depolarization to the start of ventricular depolarization. The P-P interval represents the time between successive atrial depolarizations. The R-R interval represents the time between successive ventricular depolarizations.

Question 8

When analyzing V1 to determine the presence of a bundle branch block, what should you look for?
A)A QRS complex that measures 0.12 seconds or greater and a P wave
B)A QRS complex that measures less than 0.12 seconds with no P wave
C)An inverted T wave and ST segment depression
D)ST segment elevation and a pathologic Q wave

Accepted Answer

When analyzing V1 to determine the presence of a bundle branch block, you should look for a QRS complex that measures 0.12 seconds or greater and a P wave. The presence of a wide QRS complex with a discernible P wave suggests that the block is located in the bundle branch rather than in the ventricles.

Question 9

In a left bundle branch block (LBBB), how does the QRS appear?
A)Normal in length
B)Positively deflected
C)Negatively deflected
D)Taller and deeper than normal

Accepted Answer

In a left bundle branch block (LBBB), the QRS complex is negatively deflected because the electrical impulse is delayed in reaching the left ventricle, causing the left ventricle to contract later than the right ventricle.

Question 10

Which lead is referenced to distinguish a right bundle branch block (RBBB)from a left bundle branch block (LBBB)?
A)Lead I
B)aVF
C)V6
D)V1

Accepted Answer

Lead V1 is the typically referenced lead to distinguish RBBB from LBBB. In RBBB, there is a delay in the depolarization of the right ventricle, causing a widened QRS complex with a slurred S wave in lead V1. In LBBB, there is a delay in the depolarization of the left ventricle, causing a widened QRS complex with a broad, notched R wave in lead V1.

Question 11

Where can right and left bundle branch blocks be differentiated?
A)In the precordial leads
B)In the limb leads
C)In the bipolar leads
D)In the augmented leads

Accepted Answer

Right and left bundle branch blocks can be differentiated in the precordial leads because they provide a better view of the electrical activity in the ventricles. In right bundle branch block, there is a delay in the impulse traveling through the right bundle branch, resulting in a wide QRS complex in leads V1 and V2. In left bundle branch block, there is a delay in the impulse traveling through the left bundle branch, resulting in a wide QRS complex in leads V5 and V6.

Question 12

A bundle branch block has which of the following characteristics?
A)It causes narrowed QRS complexes to appear on the ECG.
B)It accelerates depolarization of the ventricle it supplies.
C)It occurs when the bundle branches fail to conduct impulses.
D)It causes a prolonged PR interval.

Accepted Answer

A bundle branch block occurs when the electrical impulses from the bundle branches fail to conduct properly, resulting in a delay or blockage in depolarization of the ventricles. This manifests as widened QRS complexes on the ECG, rather than narrowed. It does not affect the PR interval or accelerate depolarization.

Question 13

You observe a wide QRS complex in lead II. Which lead should you check to evaluate the location of the bundle branch block?
A)Lead I
B)Lead V1
C)Lead III
D)Lead V4

Accepted Answer

Lead V1 is the best lead to evaluate the location of a bundle branch block because it shows the initial deflection of the QRS complex. In a right bundle branch block (RBBB), there is a wide QRS complex and a small initial R wave in lead V1, while in a left bundle branch block (LBBB), there is a wide QRS complex and a broad or notched initial R wave in lead V1.

Question 14

In a right bundle branch block (RBBB), how does the QRS appear?
A)Normal in length
B)Positively deflected
C)Negatively deflected
D)Taller and deeper than normal

Accepted Answer

In RBBB, the QRS complex is typically positively deflected in the right precordial leads (V1-V2) due to delayed right ventricular depolarization.

Question 15

What is the condition in which impulses generated in the atria are delayed because of damage in the ventricular electrical pathways?
A)First-degree AV block
B)Bradycardia
C)Idioventricular rhythm
D)Bundle branch block

Accepted Answer

Bundle branch block is the condition where there's a delay or blockage along the pathway that electrical impulses travel to make your heart beat, specifically affecting the ventricles due to damage in their electrical pathways.

Question 16

You are about to perform an ECG on a patient known to have sinus tachycardia with right bundle branch block. Which of the following signs and symptoms would you be likely to find in this patient?
A)Hypertension
B)Congestive heart failure
C)Unconsciousness
D)Rapid heart rate

Accepted Answer

Sinus tachycardia with right bundle branch block is characterized by a fast heart rate due to the increased activity of the sinoatrial node, as well as a delay in the conduction of electrical impulses through the right ventricle. While hypertension and congestive heart failure may be associated with certain types of heart block, they are not specific to sinus tachycardia with right bundle branch block. Unconsciousness is also unlikely to occur simply as a result of this condition.

Question 17

A bundle branch block must be considered when the QRS complex measures what length?
A)0)12 seconds or greater
B)0)06 to 0.10 seconds
C)Less than 0.06 seconds
D)0)04 to 0.08 seconds

Accepted Answer

A bundle branch block should be considered when the QRS complex measures 0.12 seconds or greater.

Question 18

The V1 tracing shown here is from a 12-lead ECG performed on a 36-year-old male patient as part of a yearly physical examination. The patient appears to be in good general health. What does this tracing show? 
A)Left bundle branch block
B)Right bundle branch block
C)Complete AV block
D)Left ventricular hypertrophy

Accepted Answer

The answer of The V1 tracing shown here is from...

Question 19

What additional patient information is needed on the ECG tracing when a bundle branch block is discovered?
A)Patient's cardiac history
B)Patient's symptoms
C)Patient's blood pressure reading
D)Patient's underlying rhythm

Accepted Answer

The underlying rhythm is important to determine the type of bundle branch block and its clinical significance.

Question 20

How is a right bundle branch block (RBBB)distinguished from a left bundle branch block (LBBB)?
A)Monitor lead V1. If the majority of the ventricular depolarization is positively deflected, it is RBBB; if the QRS is negative, it is LBBB
B)Monitor lead V1. If the majority of the ventricular depolarization is positively deflected, it is LBBB; if the QRS is negative, it is RBBB
C)Monitor leads V1 to V6 and measure the PR interval
D)Monitor leads I, II, and III and observe the P wave configuration

Accepted Answer

Monitoring lead V1 is the best lead to distinguish between RBBB and LBBB based on the majority of the ventricular depolarization being positively or negatively deflected. The PR interval and P wave configuration are not reliable indicators for differentiating between RBBB and LBBB.

Quiz 10: Bundle Branch Block

What happens when one or both of the ventricular pathways are not functioning properly due to damage or a delay from cardiac disease, drugs, or other conditions?

A patient's dysrhythmia originates from above the ventricles and you notice QRS complexes on the ECG tracing measuring 0.12 second or greater. What could be the cause of this abnormal morphology?

Which of the following statements about bundle branch block is true?

Which of the following is a characteristic of left bundle branch block?

Bundle branch block rhythm is similar to a sinus rhythm but has what distinguishing characteristic?

What rhythm is shown in this ECG tracing?

What measurement on the ECG tracing represents how long it takes for the current to travel through the ventricular myocardial tissue?

When analyzing V1 to determine the presence of a bundle branch block, what should you look for?

In a left bundle branch block (LBBB) , how does the QRS appear?

Which lead is referenced to distinguish a right bundle branch block (RBBB) from a left bundle branch block (LBBB) ?

Where can right and left bundle branch blocks be differentiated?

A bundle branch block has which of the following characteristics?

You observe a wide QRS complex in lead II. Which lead should you check to evaluate the location of the bundle branch block?

In a right bundle branch block (RBBB) , how does the QRS appear?

What is the condition in which impulses generated in the atria are delayed because of damage in the ventricular electrical pathways?

You are about to perform an ECG on a patient known to have sinus tachycardia with right bundle branch block. Which of the following signs and symptoms would you be likely to find in this patient?

A bundle branch block must be considered when the QRS complex measures what length?

The V1 tracing shown here is from a 12-lead ECG performed on a 36-year-old male patient as part of a yearly physical examination. The patient appears to be in good general health. What does this tracing show?

What additional patient information is needed on the ECG tracing when a bundle branch block is discovered?

How is a right bundle branch block (RBBB) distinguished from a left bundle branch block (LBBB) ?