Question 1

Afterload is influenced by arterial blood pressure, arterial distensibility, and arterial resistance.

Accepted Answer

Afterload is the pressure or resistance against which the ventricles must pump to eject blood. Afterload is influenced by arterial blood pressure, arterial distensibility (ability to become stretched), and arterial resistance. The less the resistance (lower afterload), the more easily blood can be ejected. Increased afterload (increased resistance) results in increased cardiac workload.

Question 2

Each ventricle holds about 300 mL of blood when it is full. They normally eject about three fourths of this volume with each contraction.

Accepted Answer

Each ventricle holds about 150 mL of blood when it is full. They normally eject about half this volume (70 to 80 mL) with each contraction. The percentage of blood pumped out of a heart chamber with each contraction is called the ejection fraction. Ejection fraction is used as a measure of ventricular function. A normal ejection fraction is between 50% and 65%.

Question 3

The two most common sites of atrioventricular (AV) block are the:&#10;A) AV node and bundle branches.&#10;B) atria and Purkinje fibers.&#10;C) bundle of His and bundle branches.&#10;D) bundle of His and Purkinje fibers.

Accepted Answer

AV block can occur at the level of the AV node, at the level of the bundle branches, or at some site in between, such as the bundle of His. The two most common sites of AV block are the AV node (nodal block) and the bundle branches (infranodal block).

Question 4

The difference between second-degree type I and type II AV block is that with:&#10;A) type I, the ventricular rhythm is regular.&#10;B) type II, the PR interval is always less than 0.12 second in duration.&#10;C) type I, the P waves occur irregularly.&#10;D) type I, the PR interval becomes progressively longer until a P wave appears without a QRS complex.

Accepted Answer

In second-degree AV block type I, the PR interval becomes progressively longer until a P wave appears without a QRS complex. In second-degree AV block type II, the PR interval is constant before each conducted QRS complex.

Question 5

A heart rate that is too fast may be associated with:&#10;A) junctional rhythm and atrial flutter.&#10;B) second-degree AV block and atrial fibrillation.&#10;C) idioventricular rhythm and ventricular tachycardia.&#10;D) supraventricular tachycardias and ventricular tachycardia.

Accepted Answer

A heart rate that is too fast may be associated with sinus tachycardia, atrial flutter or atrial fibrillation with a rapid ventricular response, supraventricular tachycardias, or ventricular tachycardia.

Question 6

In a third-degree AV block:&#10;A) the atrial rhythm (P-P interval) is irregular.&#10;B) the ventricular rhythm (R-R interval) is irregular.&#10;C) the PR interval lengthens until a P wave appears with no QRS complex.&#10;D) there is no PR interval because the atria and ventricles beat independently of each other.

Accepted Answer

In third-degree AV block, impulses generated by the SA node are blocked before reaching the ventricles so no P waves are conducted and consequently there is no PR interval. The atria and ventricles beat independently of each other. Thus, third-degree AV block is also called complete AV block.

Question 7

Which of the following types of second-degree AV block is most likely to rapidly progress rapidly to a third-degree AV block without warning?&#10;A) Second-degree AV block type I&#10;B) Second-degree AV block type II

Accepted Answer

Second-degree AV block type II occurs below the AV node, either at the bundle of His or, more commonly, at the level of the bundle branches. This type of block is more serious than second-degree AV block type I and may rapidly progress to third-degree AV block without warning. Preparations should be made for pacing when this rhythm is recognized. The use of atropine should be avoided. In this situation, atropine will usually not improve the block but will increase the rate of discharge of the SA node. This may trigger a situation in which even fewer impulses are conducted through to the ventricles and the ventricular rate is further slowed.

Question 8

Preload is:&#10;A) the force exerted on the walls of the ventricles at the end of diastole.&#10;B) the volume of blood expelled by the ventricles of the heart per minute.&#10;C) the resistance against which the left ventricle must eject its blood volume during contraction.&#10;D) the pressure exerted by the circulating blood volume on the walls of the arteries, veins, and the chambers of the heart.

Accepted Answer

Preload is the force exerted on the walls of the ventricles at the end of diastole. The volume of blood returning to the heart influences preload. More blood returning to the right atrium increases preload; less blood returning decreases preload.

Question 9

Absolute hypovolemia is a term used to describe:&#10;A) an actual fluid deficit.&#10;B) a change in tank size due to vasodilation from any cause or redistribution of body fluid to third spaces.

Accepted Answer

Hypotension may be caused by volume deficit or a vascular resistance problem. Absolute hypovolemia is a term used to describe an actual fluid deficit. In contrast, relative hypovolemia is a term used to describe a change in tank size due to vasodilation from any cause or redistribution of body fluid to third spaces.

Question 10

A third-degree AV block associated with an anterior MI is usually preceded by:&#10;A) second-degree AV block type II or an intraventricular conduction delay.&#10;B) first-degree AV block or second-degree AV block type I.&#10;C) second-degree AV block type I or ventricular tachycardia.&#10;D) first-degree AV block or an intraventricular conduction delay.

Accepted Answer

Third-degree AV block associated with an inferior MI is thought to be the result of a block above the bundle of His. It often occurs after progression from first-degree AV block or second-degree AV block type I. The resulting rhythm is usually stable because the escape pacemaker is usually junctional (narrow QRS complexes) with a ventricular rate of more than 40 beats/min.Third-degree AV block associated with an anterior MI is usually preceded by second-degree AV block type II or an intraventricular conduction delay (right or left bundle branch block). The resulting rhythm is usually unstable because the escape pacemaker is usually ventricular (wide QRS complexes) with a ventricular rate of less than 40 beats/min.

Question 11

As the left ventricle fails,&#10;A) blood builds up in the lungs.&#10;B) the liver enlarges and becomes tender.&#10;C) generalized edema of the entire body develops.&#10;D) blood backs up into the superior and inferior venae cavae.

Accepted Answer

The answer of As the left ventricle fails,&#10;A) blood builds...

Question 12

When AV block is associated with an inferior wall infarction and produces a narrow QRS complex, the block is probably located in the:&#10;A) atria.&#10;B) AV node.&#10;C) bundle branches.&#10;D) Purkinje fibers.

Accepted Answer

The answer of When AV block is associated with an...

Question 13

Cardiac output is determined by:&#10;A) heart rate &#215; stroke volume.&#10;B) blood pressure &#215; heart rate.&#10;C) systolic + diastolic pressure.&#10;D) stroke volume &#215; blood pressure.

Accepted Answer

The answer of Cardiac output is determined by:&#10;A) heart rate...

Question 14

Possible causes of relative hypovolemia include:&#10;A) spinal injury and anaphylaxis.&#10;B) hemorrhage and third-space loss.&#10;C) phlebotomy and reduced fluid intake.&#10;D) drugs that alter vascular tone, vomiting, and diarrhea.

Accepted Answer

The answer of Possible causes of relative hypovolemia include:&#10;A) spinal...

Question 15

When AV block is associated with an anterior wall infarction and produces a wide QRS complex, the block is probably located in the:&#10;A) SA node.&#10;B) AV node.&#10;C) bundle branches.&#10;D) atria.

Accepted Answer

The answer of When AV block is associated with an...

Question 16

Which of the following statements is INCORRECT regarding a first-degree AV block?&#10;A) First-degree AV block that occurs with acute myocardial infarction should be monitored closely.&#10;B) First-degree AV block may be a normal finding in individuals with no history of cardiac disease.&#10;C) Medications such as procainamide, beta-blockers, calcium channel blockers, digitalis, and amiodarone can cause a first-degree AV block.&#10;D) First-degree AV block is usually an indication for a permanent pacemaker.

Accepted Answer

The answer of Which of the following statements is INCORRECT...

Question 17

List four complications associated with MI.

Accepted Answer

The answer of List four complications associated with MI....

Question 18

List the cardiovascular system components necessary to ensure normal body tissue perfusion.

Accepted Answer

The answer of List the cardiovascular system components necessary to...

Question 19

Define cardiogenic shock.

Accepted Answer

The answer of Define cardiogenic shock....

Deck 6: Evidence-Based Practice