The Heart

Question 1

A 60-year-old woman has a resting heart rate of 70 beats/min, arterial pressure is 130/85 mm Hg, and body temperature is normal. Her pressure-volume diagram of the left ventricle is shown above.

Question 2

1. What is her cardiac output in milliliters per minute?

A)2000

B)3000

C)4000

D)6000

E)7000

Question 3

When does the second heart sound occur in the ventricular pressure–volume relationship?

A) At point D

B)Between point A and point B

C)Between point B and point C

D)Between point C and point D

E)Between point D and point A

Question 4

When does the third heart sound occur in the ventricular pressure–volume relationship?

A)At point D

B)Between point A and point B

C)Between point B and point C

D)Between point C and point D

E)Between point D and point A

Question 5

What is her ventricular ejection fraction?

A)33%

B)50%

C)60%

D)67%

E)80%

Question 6

In which phase of the ventricular muscle action potential is the potassium permeability the highest?

A)0

B)1

C)2

D)3

E)4

Question 7

In a resting adult, the typical ventricular ejection fraction has what value?

A)20%

B)30%

C)40%

D)60%

E)80%

Question 8

A 30-year-old man has an ejection fraction of 0.25 and an end systolic volume of 150 ml. What is his end diastolic volume?

A)50 ml

B)100 ml

C)125 ml

D)200 ml

E)250 m

Question 9

Which of the following statements about cardiac muscle is most accurate?

A)The T-tubules of cardiac muscle can store much less calcium than T-tubules in skeletal muscle

B)The strength and contraction of cardiac muscle depends on the amount of calcium surrounding cardiac myocytes

C)In cardiac muscle the initiation of the action potential causes an immediate opening of slow calcium channels

D)Cardiac muscle repolarization is caused by opening of sodium channels

E)Mucopolysaccharides inside the T-tubules bind chloride ions

Question 10

A 60-year-old man’s EKG shows that he has an R-R interval of 0.55 sec. Which of the following best explains his condition?

A)He has fever

B)He has a normal heart rate

C)He has excess parasympathetic stimulation of the S-A node

D)He is a trained athlete at rest

E)He has hyperpolarization of the S-A node

Question 11

A 60-year-old man’s EKG shows that he has an R-R interval of 0.55 sec. Which of the following best explains his condition?

A)He has fever

B)He has a normal heart rate

C)He has excess parasympathetic stimulation of the S-A node

D)He is a trained athlete at rest

E)He has hyperpolarization of the S-A node

Question 12

Which of the following events occurs at the end of the period of ventricular ejection?

A)A-V valves close

B)Aortic valve opens

C)Aortic valve remains open

D)A-V valves open

E)Pulmonary valve closes

Question 13

Which of the following phases of the cardiac cycle follows immediately after the beginning of the QRS wave?

A)Isovolumic relaxation

B)Ventricular ejection

C)Atrial systole

D)Diastasis

E)Isovolumic contraction

Question 14

Which of the following conditions will result in a dilated, flaccid heart?

A)Excess calcium ions in the blood

B)Excess potassium ions in the blood

C)Excess sodium ions in the blood

D)Increased sympathetic stimulation

E)Increased norepinephrine concentration in the blood

Question 15

A 25-year-old, well-conditioned athlete weighs 80 kg (176 lb). During maximal sympathetic stimulation, what is the plateau level of his cardiac output function curve?

A)3 L/min

B)5 L/min

C)10 L/min

D)13 L/min

E)25 L/min

Question 16

Which of the following events is associated with the first heart sound?

A)Closing of the aortic valve

B)Inrushing of blood into the ventricles during diastole

C)Beginning of diastole

D)Opening of the A-V valves

E)Closing of the A-V valves

Question 17

Which of the following conditions at the A-V node will cause a decrease in heart rate?

A)Increased sodium permeability

B)Decreased acetylcholine levels

C)Increased norepinephrine levels

D)Increased potassium permeability

E)Increased calcium permeability

Question 18

Sympathetic stimulation of the heart

A)Releases acetylcholine at the sympathetic endings

B)Decreases sinus nodal discharge rate

C)Decreases excitability of the heart

D)Releases norepinephrine at the sympathetic endings

E)Decreases cardiac contractility

Question 19

What is the normal total delay of the cardiac impulse in the A-V node plus bundle?

A)0.22 sec

B)0.18 sec

C)0.16 sec

D)0.13 sec

E)0.09 sec

Question 20

Which of the following best explains how sympathetic stimulation affects the heart?

A)Permeability of the S-A node to sodium decreases

B)Permeability of the A-V node to sodium decreases

C)Permeability of the S-A node to potassium increases

D)There is an increased rate of upward drift of the resting membrane potential of the S-A node

E)Permeability of the cardiac muscle to calcium decreases

Question 21

Which of the following structures will have the slowest rate of conduction of the cardiac action potential?

A)Atrial muscle

B)Anterior internodal pathway

C)A-V bundle fibers

D)Purkinje fibers

E)Ventricular muscle

Question 22

f the S-A node discharges at 0.00 seconds, when will the action potential normally arrive at the epicardial surface at the base of the left ventricle?

A)0.22 sec

B)0.18 sec

C)0.16 sec

D)0.12 sec

E)0.09 sec

Question 23

If the S-A node discharges at 0.00 seconds, when will the action potential normally arrive at the A-V bundle (bundle of His)?

A)0.22 sec

B)0.18 sec

C)0.16 sec

D)0.12 sec

E)0.09 sec

Question 24

Which of the following conditions at the S-A node will cause heart rate to decrease?

A)Increased norepinephrine levels

B)Increased sodium permeability

C)Increased calcium permeability

D)Increased potassium permeability

E)Decreased acetylcholine levels

Question 25

Which of the following are caused by acetylcholine?

A)Hyperpolarization of the S-A node

B)Depolarization of the A-V node

C)Decreased permeability of the S-A node to potassium ions

D)Increased heart rate

E)Increased permeability of the cardiac muscle to calcium ions

Question 26

What is the membrane potential (threshold level) at which the S-A node discharges?

A)−40 mV

B)−55 mV

C)−65 mV

D)−85 mV

E)−105 mV

Question 27

Which of the following conditions at the A-V node will cause a decrease in heart rate?

A)Increased sodium permeability

B)Decreased acetylcholine levels

C)Increased norepinephrine levels

D)Increased potassium permeability

E)Increased calcium permeability

Question 28

If the ventricular Purkinje fibers become the pacemaker of the heart, what is the expected heart rate?

A)30/min

B)50/min

C)65/min

D)75/min

E)85/min

Question 29

What is the normal total delay of the cardiac impulse in the A-V node and the A-V bundle system?

A)0.03 sec

B)0.06 sec

C)0.09 sec

D)0.13 sec

E)0.17 sec

Question 30

What is the resting membrane potential of the sinus nodal fibers?

A)−100 mV

B)−90 mV

C)−80 mV

D)−55 mV

E)−20 mV

Question 31

If the Purkinje fibers, situated distal to the A-V junction, become the pacemaker of the heart, what is the expected heart rate?

A)30/min

B)50/min

C)60/min

D)70/min

E)80/min

Question 32

Sympathetic stimulation of the heart normally causes which of the following conditions?

A)Acetylcholine release at the sympathetic endings

B)Decreased heart rate

C)Decreased rate of conduction of the cardiac impulse

D)Decreased force of contraction of the atria

E)Increased force of contraction of the ventricles

Question 33

When recording lead I on an EKG, the right arm is the negative electrode, and the positive electrode is the

A)left arm

B)left leg

C)right leg

D)left arm + left leg

E)right arm + left leg

Question 34

When recording lead aVL on an EKG, the positive electrode is the

A)left arm

B)left leg

C)right leg

D)left arm + left leg

E)right arm + left leg

Question 35

A 70-year-old man was had the following EKG during his annual physical exam. What is his Q-T interval?

A)0.12 sec

B)0.16 sec

C)0.22 sec

D)0.30 sec

E)0.40 sec

Question 36

What is the heart rate in the following EKG?

A)64

B)70

C)88

D)94

E)104

Question 37

What is the normal QT interval?

A)0.03 seconds

B)0.13 seconds

C)0.16 seconds

D)0.20 seconds

E)0.35 seconds

Question 38

When recording lead II on an EKG, the positive electrode is the

A)left arm

B)left leg

C)right leg

D)left arm + left leg

E)right arm + left leg

Question 39

When recording lead III on an EKG, the negative electrode is the

A) left arm

B)left leg

C)right leg

D)left arm + left leg

E)right arm + left leg

Question 40

A 65-year-old man had an EKG recorded at a local emergency room following a biking accident. His weight was 80 kg and his aortic blood pressure was 160/90 mm Hg. The QRS voltage was 0.5 mV in lead I and 1.5 mV in lead III. What is the QRS voltage in lead II?

A)0.5 mV

B)1.0 mV

C)1.5 mV

D)2.0 mV

E)2.5 mV

Question 41

A ventricular depolarization wave when traveling −90° in the frontal plane will cause a large negative deflection in which lead?

A)aVR

B)aVL

C)Lead II

D)Lead III

E)aVF

Question 42

A 60-year-old woman had the following EKG recorded at a local emergency room following an automobile accident. Her weight was 70 kg and her aortic blood pressure was 140/80 mm Hg.

41.What is the mean electrical axis calculated from standard leads I, II, and III shown in her EKG?

A)−90°

B)−50°

C)−12°

D)+100°

E)+170°

42.What is the heart rate using lead I for the calculation?

A)70

B)88

C)100

D)112

E)148

43.What is her likely diagnosis?

A)Mitral valve stenosis

B)Left bundle branch block

C)Pulmonary valve stenosis

D)Right bundle branch block

E)Left ventricular hypertrophy

Question 43

Which of the following conditions will usually result in right axis deviation in an EKG?

A)Systemic hypertension

B)Aortic valve stenosis

C)Aortic valve regurgitation

D)Excess abdominal fat

E)Pulmonary hypertension

Question 44

A ventricular depolarization wave when traveling 60° in the frontal plane will cause a large positive deflection in which of the following leads?

A)aVR

B)aVL

C)Lead I

D)Lead II

E)aVF

Question 45

A male long-term smoker who is 62 years old weighs 250 lb. He had the following EKG recorded at his local hospital.

46. Which of the following is the mean electrical axis calculated from standard leads I, II, and III shown in his EKG?

A)−110°

B)−20°

C)+90°

D)+105°

E)+180°

47.Which of the following is the likely diagnosis?

A)Left ventricular hypertrophy

B)Left bundle branch block

C)Tricuspid stenosis

D)Right bundle branch block

E)Right ventricular hypertrophy

Question 46

A 60-year-old woman has lost some ability to perform normal household tasks and is not feeling well. An EKG shows a QRS complex with a width of 0.20 sec, the T wave is inverted in lead I, and the R wave has a large negative deflection in lead III. Which of the following is the likely diagnosis?

A)Right ventricular hypertrophy

B)Left bundle branch block

C)Pulmonary valve stenosis

D)Right bundle branch block

E)Left ventricular hypertrophy

Question 47

A 70-year-old woman sought assistance at a hospital emergency department because she is experiencing chest pain. Based on the following EKG tracing, which of the following is the likely diagnosis?

A)Acute anterior infarction in the left ventricle of the heart

B)Acute anterior infarction in the right ventricle of the heart

C)Acute posterior infarction in the left ventricle of the heart

D)Acute posterior infarction in the right ventricle of the heart

E)Right ventricular hypertrophy

Question 48

A 30-year-old man had his EKG measured at his physician’s office, but his records were lost. The EKG technician remembered that the QRS deflection was large and positive in lead aVF and 0 in lead I. What is the mean electrical axis in the frontal plane?

A)90°

B)60°

C)0°

D)−60°

E)−90°

Question 49

Which of the following is most likely at the “J point” in an EKG of a patient with a damaged cardiac muscle?

A)Entire heart is depolarized

B)All the heart is depolarized except for the damaged cardiac muscle

C)About half the heart is depolarized

D)All of the heart is repolarized

E)All of the heart is repolarized except for the damaged cardiac muscle

Question 50

A 50-year-old man is a new employee at ABC Software. The EKG shown here was recorded during a routine physical examination. His likely diagnosis is which of the following?

A)Chronic systemic hypertension

B)Chronic pulmonary hypertension

C)Second-degree heart block

D)Paroxysmal tachycardia

E)Tricuspid valve stenosis

Question 51

A 55-year-old man had his EKG measured at an annual physical, and his net deflection (R wave minus Q or S wave) in standard limb lead I is −1.2 mV. Standard limb lead II has a net deflection of +1.2 mV. What is the mean electrical axis of his QRS?

A)−30°

B)+30°

C)+60°

D)+120°

E)−120°

Question 52

A 65-year-old patient with a heart murmur has a mean QRS axis of 120°, and the QRS complex lasts 0.18 sec. Which of the following is the likely diagnosis?

A)Aortic valve stenosis

B)Aortic valve regurgitation

C)Pulmonary valve stenosis

D)Right bundle branch block

E)Left bundle branch block

Question 53

A 60-year-old woman tires easily. Her EKG shows a QRS complex that is positive in the aVF lead and negative in standard limb lead I. A likely cause of this condition is which of the following?

A)Chronic systemic hypertension

B)Pulmonary hypertension

C)Aortic valve stenosis

D)Aortic valve regurgitation

Question 54

A 60-year-old woman came to the hospital emergency department and complained of chest pain. Based on the EKG tracing shown here, which of the following is the most likely diagnosis?

A)Acute anterior infarction in the base of the heart

B)Acute anterior infarction in the apex of the heart

C)Acute posterior infarction in the base of the heart

D)Acute posterior infarction in the apex of the heart

E)Right ventricular hypertrophy

Question 55

A 50-year-old man has a blood pressure of 140/85 and weighs 200 lb. He reports that he is not feeling well, his EKG has no P-waves, he has a heart rate of 46, and the QRS complexes occur regularly.

What is his likely condition?

A)First-degree heart block

B)Second-degree heart block

C)Third-degree heart block

D)Sinoatrial heart block

E)Sinus bradycardia

Question 56

An 80-year-old man had an EKG taken at his local doctor’s office, and the diagnosis was atrial fibrillation. Which of the following statements are likely conditions in someone with atrial fibrillation?

A)Ventricular fibrillation normally accompanies atrial fibrillation

B)P waves of the EKG are strong

C)Rate of ventricular contraction is irregular and fast

D)Atrial “a” wave is normal

E)Atria have a smaller volume than normal

Question 57

Circus movements in the ventricle can lead to ventricular fibrillation. Which of the following conditions in the ventricular muscle will increase the tendency for circus movements?

A)Decreased refractory period

B)Low extracellular potassium concentration

C)Increased refractory period

D)Shorter conduction pathway (decreased ventricular volume)

E)Increase in parasympathetic impulses to the heart

Question 58

A 75-year-old man goes to the hospital emergency department and faints. Five minutes later he is alert. An EKG shows 75 P waves per minute and 35 QRS waves per minute with a normal QRS width. Which of the following is the likely diagnosis?

A)First-degree A-V block

B)Stokes-Adams syndrome

C)Atrial paroxysmal tachycardia

D)Electrical alternans

E)Atrial premature contractions

Question 59

A 60-year-old man weighing 220 lb had the following EKG, which shows the standard lead II. What is his diagnosis?

A)A-V nodal rhythm

B)First-degree A-V heart block

C)Second-degree A-V heart block

D)Third-degree A-V heart block

E)Atrial flutter

Question 60

A 35-year-old woman had unusual sensations in her chest after she smoked a cigarette. Her EKG is shown here. Which of the following is the likely diagnosis?

A)Premature contraction originating in the atrium

B)Premature contraction originating high in the A-V node

C)Premature contraction originating low in the A-V node

D)Premature contraction originating in the apex of the ventricle

E)Premature contraction originating in the base of the ventricle

Question 61

A 55-year-old man had the following EKG recorded at his doctor’s office during a routine physical examination.

63. What is his diagnosis?

A)Normal EKG

B)Atrial flutter

C)High A-V junctional pacemaker

D)Middle A-V junctional pacemaker

E)Low A-V junctional pacemaker

64.What is his ventricular heart rate in beats per minute?

A)37.5

B)60

C)75

D)100

E)120

Question 62

A 60-year-old woman has been diagnosed with atrial fibrillation. Which of the following statements best describe this condition?

A)Ventricular rate of contraction is 140 beats/min

B)P waves of the EKG are pronounced

C)Ventricular contractions occur at regular intervals

D)QRS waves are more pronounced than normal

E)Atria are smaller than norma

Question 63

Which of the following is most characteristic of atrial fibrillation?

A)Occurs less frequently in patients with atrial enlargement

B)Ventricular heart rate is about 40 beats per min

C)Efficiency of ventricular pumping is decreased 20 to 30 percent

D)Ventricular beat is regular

E)Atrial P wave is easily seen

Question 64

A 65-year-old woman who had a myocardial infarction 10 days ago returns to her family physician’s office and reports that her pulse rate may be rapid. Based on the above EKG, which of the following is the likely diagnosis?

A)Stokes-Adams syndrome

B)Atrial fibrillation

C)A-V nodal tachycardia

D)Atrial paroxysmal tachycardia

E)Ventricular paroxysmal tachycardia

Question 65

A 65-year-old man had the EKG shown here recorded at his annual physical examination. Which of the following is the likely diagnosis?

A)Atrial paroxysmal tachycardia

B)First-degree A-V block

C)Second-degree A-V block

D)Third-degree A-V block

E)Atrial flutter

Question 66

Which of the following decreases the risk of ventricular fibrillation?

A)Dilated heart

B)Increased ventricular refractory period

C)Decreased electrical conduction velocity

D)Exposure of the heart to 60-cycle alternating current

E)Epinephrine administration

Question 67

Which of the following occurs after the heart is stimulated with a 60-cycle alternating current?

A)Velocity of conduction through the heart muscle decreases

B)Longer ventricular refractory period

C)Decreased tendency for circus movements

D)Decreased tendency for ventricular fibrillation

Question 68

Which of the following statements best describes a patient with premature atrial contraction?

A)Pulse taken from the radial artery immediately following the premature contraction will be weak

B)Stroke volume immediately following the premature contraction will be increased

C)P wave is never seen

D)Probability of these premature contractions occurring is decreased in people with a large caffeine intake

E) Causes the QRS interval to be lengthened

Question 69

A male patient had a myocardial infarction at age 55. He is now 63 years old. Standard limb lead I is shown here.

72.What is his heart rate?

A)40 beats/min

B)50 beats/min

C)75 beats/min

D)100 beats/min

E)150 beats/min

73.What is his current diagnosis?

A)Sinus tachycardia

B)First-degree heart block

C)Second-degree heart block

D)ST segment depression

E)Third-degree heart block

Question 70

A 55-year-old man has been diagnosed with Stokes-Adams syndrome. Two minutes after the syndrome starts to cause active blockade of the cardiac impulse, which of the following is the pacemaker of the heart?

A)Sinus node

B)A-V node

C)Purkinje fibers

D)Cardiac septum

E)Left atrium

Question 71

If the origin of the stimulus that causes atrial paroxysmal tachycardia is near the A-V node, which of the following statements about the P-wave in standard limb lead I is most accurate?

A)P wave will originate in the sinus node

B)It will be upright

C)It will be inverted

D)P wave will be missing

Question 72

A 45-year-old man had the EKG below recorded at his annual physical. Which of the following is the likely diagnosis?

A)Atrial paroxysmal tachycardia

B)First-degree A-V block

C)Second-degree A-V block

D)Ventricular paroxysmal tachycardia

E)Atrial flutter

Question 73

A 60-year-old woman sees her physician for her annual physical examination. The physician orders an EKG, which is shown below. Which of the following is the likely diagnosis?

A)First-degree A-V block

B)Second-degree A-V block

C)Third-degree A-V block

D)Atrial paroxysmal tachycardia

E)Atrial fibrillation

Question 74

An 80-year-old man went to his family physician for his annual checkup, and his EKG tracing is shown here.

78.What is his heart rate?

A)105

B)95

C)85

D)75

E)40

79.Which of the following is the likely diagnosis?

A)Left bundle branch block

B)First-degree A-V block

C)Second-degree A-V block

D)Electrical alternans

E)Complete A-V block