Question 1

The QRS complex on a typical ECG represents&#10;A)depolarization of atrial muscle.&#10;B)depolarization of ventricular muscle.&#10;C)repolarization of ventricular muscle.&#10;D)ventricular diastole.

Accepted Answer

The QRS complex represents depolarization of ventricular muscle cells.The Q portion is the initial downward deflection,the R portion is the initial upward deflection,and the S portion is the return to the baseline (isoelectric point).

Question 2

If the PR interval is longer than normal on a typical ECG tracing,one can assume that&#10;A)the patient has tachycardia.&#10;B)the patient has normal sinus rhythm.&#10;C)an atrioventricular (AV)node block is present.&#10;D)the patient has bradycardia.

Accepted Answer

If the PR interval is prolonged,it can be deduced that an AV block is present.The PR interval is normally 0.12 to 0.20 seconds (3 to 5 small squares).Longer intervals indicate that the impulse is being delayed from entering the ventricles,and the condition is designated AV block.

Question 3

All of the following are related EXCEPT&#10;A)AV node.&#10;B)Purkinje fibers.&#10;C)SA node.&#10;D)mitral valve.

Accepted Answer

Working cells are the cardiac muscle or myocardium of the atria and ventricles.Specialized cells include the sinoatrial (SA)node,atrioventricular (AV)node,bundle of His,and Purkinje fibers.These cells originate in and transmit electrical impulses across the myocardium and regulate the rhythm of a cardiac cycle.The mitral valve is not part of the cardiac conduction system.

Question 4

A possible complication of patients with a history of atrial fibrillation is&#10;A)right coronary artery stenosis.&#10;B)left coronary artery stenosis.&#10;C)atrial emboli formation.&#10;D)AV node bundle block.

Accepted Answer

One of the most common cardiac arrhythmias is atrial fibrillation.Additional ectopic pacemaker firings in the atria exceed those of the SA node,creating a quiver of the atria syncytium instead of a full contraction.Although this arrhythmia is not life threatening,the formation of atrial emboli is a potential complication.

Question 5

A widened QRS complex on an ECG tracing could represent&#10;A)ventricular hypertrophy.&#10;B)ventricular-paced rhythm.&#10;C)pacemaker tissue that is below the AV node.&#10;D)all of the above.

Accepted Answer

The duration of the QRS complex should not exceed 0.12 seconds (3 small squares).A widened complex indicates ventricular enlargement (hypertrophy)or that ventricular depolarization is being initiated by pacemaker tissue below the AV node,for example,ventricular-paced rhythm.In this example,one ventricle depolarizes first,and the current must spread into the second ventricle.This takes more time than when the current spreads down the bundle of His into both ventricles simultaneously.

Question 6

A dual-wire ICD places electrode tips in the&#10;A)right atrium and right ventricle.&#10;B)right and left ventricles.&#10;C)right and left atria.&#10;D)left atrium and left ventricle.

Accepted Answer

Arrhythmias may be treated with an implantable device such as a cardiac pacemaker or an implantable cardioverter-defibrillator (ICD).In a dual-wired unit,the electrodes are positioned in the right atrium and right ventricle.

Question 7

For a cardiac cell to return to its resting membrane potential,&#10;A)repolarization of the cell membrane must occur.&#10;B)a nerve impulse must be initiated by the Purkinje fibers.&#10;C)depolarization of the cardiac cell membrane must occur.&#10;D)none of the above are correct.

Accepted Answer

All cardiac cell membranes are positively charged on their outer surfaces.When the cell is stimulated,movement of ions in and out of the membrane alters its charge,reversing the resting potential.This period is referred to as depolarization.Reversal of ion flow reestablishes a positive charge to the outside of the membrane,a process called repolarization,which returns the membrane to its resting membrane potential.

Question 8

The cardiac arrhythmia of bradycardia generally involves abnormalities to&#10;A)the SA node.&#10;B)Purkinje fibers of the left atrium.&#10;C)the atrioventricular node.&#10;D)both a and c.

Accepted Answer

Cardiac arrhythmia is caused by abnormalities of the heart that negatively interfere with its neural conduction system and consequently impact cardiac output.Bradycardia typically involves either SA or AV node abnormalities.

Question 9

Cardioversion therapy can be used to treat&#10;A)ventricular fibrillation.&#10;B)atrial-related arrhythmias.&#10;C)V-tach.&#10;D)all of the above.

Accepted Answer

Cardioversion therapy is useful for treating atrial-related causes of arrhythmias,including atrial fibrillation.It involves external shock therapy to the chest to restore normal cardiac rhythm.In severe cases of ventricular tachycardia or fibrillation,electric shock defibrillation therapy is administered.

Question 10

The polarity that exists across a cardiac cell membrane is maintained by an active transport process known as&#10;A)the cardiac cycle.&#10;B)fibrillation.&#10;C)sodium-potassium ion pump.&#10;D)pinocytosis.

Accepted Answer

All cardiac cell membranes are positively charged on their outer surfaces owing to the relative distribution of cations.This resting membrane potential is maintained by an active transport mechanism called the sodium-potassium ion pump.

Question 11

Heart rates above 100 beats/min in an adult is termed&#10;A)bradycardia.&#10;B)tachycardia.&#10;C)cardiac ectopia.&#10;D)fibrillation.

Accepted Answer

The answer of Heart rates above 100 beats/min in an...

Question 12

A cardiac arrhythmia that is life threatening and provides no effective cardiac output is&#10;A)atrial fibrillation.&#10;B)V-tach.&#10;C)V-fib.&#10;D)PVC.

Accepted Answer

The answer of A cardiac arrhythmia that is life threatening...

Question 13

Referring to the choices below,the normal flow of electrical impulse through the cardiac conduction system of the heart follows what sequence of events?
1)Purkinje fibers
2)AV node
3)SA node
4)Bundle of His
5)Interventricular node (IV node)

A)3,1,4,5
B)2,3,5,1
C)3,2,4,1
D)3,5,4,1

Accepted Answer

The answer of Referring to the choices below,the normal flow...

Question 14

An effective method for treating select cardiac arrhythmias is the use of high-frequency alternating current to destroy strategic cardiac tissue and reroute the cardiac impulses generated.These procedures are known as

A)selective coronary angioplastic repairs.
B)cardiac ablation treatments.
C)left ventriculograms.
D)cardiac valvular replacements.

Accepted Answer

The answer of An effective method for treating select cardiac...

Question 15

Adequate perfusion of human tissue generally requires&#10;A)a diastolic pressure of 20 mm Hg.&#10;B)a systolic pressure of 90 mm Hg or greater.&#10;C)occasional arrhythmias to bring the heart into a rhythmic cardiac cycle.&#10;D)a diastolic pressure of at least 90 mm Hg.

Accepted Answer

The answer of Adequate perfusion of human tissue generally requires&#10;A)a...

Deck 16: Basic Cardiac Monitoring: The Electrocardiogram