Deck 16: Basic Cardiac Monitoring: The Electrocardiogram

Question 1

The QRS complex on a typical ECG represents

A)depolarization of atrial muscle.
B)depolarization of ventricular muscle.
C)repolarization of ventricular muscle.
D)ventricular diastole.

Answer 1

B
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

A)the patient has tachycardia.
B)the patient has normal sinus rhythm.
C)an atrioventricular (AV)node block is present.
D)the patient has bradycardia.

Answer 2

C
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

A)AV node.
B)Purkinje fibers.
C)SA node.
D)mitral valve.

Answer 3

D
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

A)right coronary artery stenosis.
B)left coronary artery stenosis.
C)atrial emboli formation.
D)AV node bundle block.

Question 5

A widened QRS complex on an ECG tracing could represent

A)ventricular hypertrophy.
B)ventricular-paced rhythm.
C)pacemaker tissue that is below the AV node.
D)all of the above.

Question 6

A dual-wire ICD places electrode tips in the

A)right atrium and right ventricle.
B)right and left ventricles.
C)right and left atria.
D)left atrium and left ventricle.

Question 7

For a cardiac cell to return to its resting membrane potential,

A)repolarization of the cell membrane must occur.
B)a nerve impulse must be initiated by the Purkinje fibers.
C)depolarization of the cardiac cell membrane must occur.
D)none of the above are correct.

Question 8

The cardiac arrhythmia of bradycardia generally involves abnormalities to

A)the SA node.
B)Purkinje fibers of the left atrium.
C)the atrioventricular node.
D)both a and c.

Question 9

Cardioversion therapy can be used to treat

A)ventricular fibrillation.
B)atrial-related arrhythmias.
C)V-tach.
D)all of the above.

Question 10

The polarity that exists across a cardiac cell membrane is maintained by an active transport process known as

A)the cardiac cycle.
B)fibrillation.
C)sodium-potassium ion pump.
D)pinocytosis.

Question 11

Heart rates above 100 beats/min in an adult is termed

A)bradycardia.
B)tachycardia.
C)cardiac ectopia.
D)fibrillation.

Question 12

A cardiac arrhythmia that is life threatening and provides no effective cardiac output is

A)atrial fibrillation.
B)V-tach.
C)V-fib.
D)PVC.

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

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.

Question 15

Adequate perfusion of human tissue generally requires

A)a diastolic pressure of 20 mm Hg.
B)a systolic pressure of 90 mm Hg or greater.
C)occasional arrhythmias to bring the heart into a rhythmic cardiac cycle.
D)a diastolic pressure of at least 90 mm Hg.