Elsevier Quizzes Chapter 31: Cardio

Which anatomic feature of the heart directly stimulates ventricular contractions?

Purkinje fibers

Which are the major factors that influence BP? Select all that apply. 1. Capillary refill 2. Cardiac output 3. Oxygen saturation 4. Pulmonary pressure 5. Systemic vascular resistance

2. Cardiac output 5. Systemic vascular resistance Rationale: The two main factors influencing BP are cardiac output and systemic vascular resistance. Capillary refill, oxygen saturation, and pulmonary pressure do not influence BP.

The BP of a patient is 90/60 mm Hg. What should the nurse document as the patient's pulse pressure? Record the answer using a whole number. ________ mm Hg

30 Rationale: The difference between the systolic BP (SBP) and diastolic BP (DBP) is the pulse pressure. The patient's SBP is 90, and the DBP is 60; therefore the pulse pressure is 90 - 60 = 30 mm Hg.

The nurse is teaching a group of nursing students about the anatomic characteristics of the heart. Which information would the nurse include? 1. The right and the left atria are similar in size. 2. The atrial myocardium is thicker than that of the ventricles. 3. The right ventricular wall is three times thicker than the left ventricle. 4. The left ventricle is thicker to pump the blood into the systemic circulation.

4. The left ventricle is thicker to pump the blood into the systemic circulation. Rationale: The left ventricle is thicker because it needs to pump the blood into circulation. The right and left atria are different sizes and have different wall thicknesses. The atrial myocardium is thinner than that of the ventricles. The left ventricular wall is two or three times thicker than the right ventricular wall.

In what order does blood flow through the heart?

right atrium, tricuspid valve, right ventricle, pulmonic valve, pulmonic artery, lungs, left atrium, mitral valve, left ventricle aortic valve, aorta, body

How many seconds does it take for the ventricular conduction system to deliver an electrical impulse? Use a leading zero, if applicable. Record the answer to the second decimal place. __ second(s)

0.12 seconds Rationale: The ventricular conduction system delivers the impulse within 0.12 second. The action potential is generated from the sinoatrial node. It travels through the conduction system, including the atrioventricular (AV) node, bundle of His, and the left and right bundle branches. The action potential moves through the walls of both ventricles by means of Purkinje fibers.

What does the P wave represent? 1. Atrial depolarization 2. Ventricular depolarization 3. Excitation of the Purkinje fibers 4. Conduction through the AV valves

1. Atrial depolarization Rationale: The P wave indicates atrial depolarization. The QRS complex represents depolarization from the AV node throughout the ventricles. The PR interval represents the time it takes the impulse to spread through the atria, AV node, bundle of His, bundle branches, and Purkinje fibers to the point immediately preceding ventricular contraction. The U wave, if seen, represents repolarization of Purkinje fibers, or the U wave may be associated with hypokalemia.

Which portion of the vascular system exchanges cellular nutrients and metabolic end products? 1. Capillary vessels 2. Smooth muscle of the arteriole 3. Endothelial layer of the arteries 4. Elastic middle layer of the veins

1. Capillary vessels Rationale: The exchange of cellular nutrients and metabolic end products takes place through the thin-walled capillaries, which connect the arterioles and the venules. Exchange of cellular nutrients and metabolic end products does not occur in the arteriole, arteries, or veins.

A patient presents to an emergency department with angina. Which parameters in the laboratory report would indicate myocardial infarction? Select all that apply. 1. High troponin level 2. High cholesterol level 3. Elevated homocysteine (Hcy) level 4. Increased C-reactive protein (CRP) level 5. High troponin level

1. High troponin level 5. High troponin level Rationale: Many chemical parameters may indicate and confirm the presence of a myocardial infarction. Cardiac-specific troponin levels are specific to heart muscles. Their levels are usually very low, and any increase indicates myocardial injury. Creatinine kinase (CK) is a protein found skeletal muscle, brain and nervous tissue, and the heart. CK-MB is heart specific, and high levels of this protein are indicative of myocardial infarction. A high cholesterol level indicates an increased risk of cardiovascular diseases but is not suggestive of myocardial infarction. C-reactive protein is elevated during inflammation. Homocysteine levels may be elevated in people who have a high risk of coronary artery disease.

Which response occurs after a rupture on the endothelial surface of an artery? 1. Initiates coagulation cascade 2. Decreases viscosity of the blood 3. Promotes blood flow in the artery 4. Decreases platelet aggregation at the site

1. Initiates coagulation cascade Rationale: The endothelium is the innermost layer of the arteries in the body. After damage to any part of the artery, it initiates cascade formation and aids in the formation of a fibrin clot to reduce the risk of bleeding. The endothelium does not decrease the viscosity of the blood in the artery in either normal or damaged conditions. The endothelium promotes blood flow in the artery during normal conditions but not after a rupture. The endothelium increases platelet aggregation at the ruptured site to repair the ruptured part of the epithelial surface.

The nurse is providing information about cardiac output to a group of nursing students. Which information about calculating cardiac output should be included? 1. It is calculated by multiplying the patient's stroke volume by the heart rate. 2. It is the average amount of blood ejected during one complete cardiac cycle. 3. It is determined by measuring the electrical activity of the heart and the patient's heart rate. 4. It is the patient's average resting heart rate multiplied by the patient's mean arterial BP

1. It is calculated by multiplying the patient's stroke volume by the heart rate. Rationale: Cardiac output is calculated by multiplying the patient's stroke volume and heart rate, thus identifying how much blood is pumped by the heart over a one-minute period. The amount of blood ejected from the heart in one minute is the stroke volume. The electrical activity of the heart and heart rate would not provide enough information to calculate cardiac output. The heart rate and blood pressure would not provide direct information to calculate cardiac output.

A patient has a severe blockage in the left coronary artery. Which cardiac structures will likely be affected by the blockage? Select all that apply. 1. Left atrium 2. Left ventricle 3. Bundle of His 4. Interventricular septum 5Atrioventricular (AV) node

1. Left atrium 2. Left ventricle 4. Interventricular septum Rationale: The left coronary artery arises from the aorta and divides into two main branches: the left anterior descending artery and the left circumflex artery. These arteries supply the left atrium, the left ventricle, the interventricular septum, and a portion of the right ventricle. The AV node and bundle of His are usually supplied by the right coronary artery.

Which factors affect a patient's stroke volume? Select all that apply. 1. Preload 2. Afterload 3. Contractility 4. Cardiac index 5. Cardiac output

1. Preload 2. Afterload 3. Contractility Rationale: Increased or decreased preload, afterload, and contractility alter the stroke volume of the blood. The cardiac index and cardiac output are affected by stroke volume but do not affect the stroke volume of the blood.

A patient is admitted to the hospital with chest pain. Which diagnostic studies would the nurse expect to be prescribed? Select all that apply. 1. Stress test 2. Chest x-ray 3. Funduscopy 4. Electrocardiogram 5. Electroencephalogram

1. Stress test 2. Chest x-ray 4. Electrocardiogram Rationale: A patient with chest pain undergoes tests to assess cardiovascular status. A stress test shows the function of the heart under stress or exercise. A chest x-ray helps one to understand the status of structures in the chest and can assist in understanding any abnormality. An electrocardiogram helps one to understand the electrical activity of the heart and is extremely important while assessing a patient with cardiac troubles. A funduscopy is done to examine the eyes and is not related to the cardiovascular system. An electroencephalogram is done to examine the brain and neurologic system.

A patient presents to the emergency department reporting chest pain. Which component of the patient's blood work would most specifically indicate an acute myocardial infarction (MI)? 1. Troponin 2. Myoglobin 3. Creatine kinase (CK) 4. C-reactive protein (CRP)

1. Troponin Rationale: Troponin is the biomarker of choice in the diagnosis of MI, with sensitivity and specificity that exceed those of other markers. CK enzymes are found in a variety of organs and tissues. Myoglobin elevation is a sensitive indicator of very early myocardial injury but lacks specificity for MI. CRP levels are not used to diagnose acute MI; rather, an increased level has been linked with the presence of atherosclerosis.

Which blood studies would the nurse expect to see prescribed in a focused evaluation of a patient with cardiac disease? Select all that apply. 1. Troponin 2. Homocysteine 3. C-reactive protein 4. Blood urea nitrogen 5. Thyroid-stimulating hormone

1. Troponin 2. Homocysteine 3. C-reactive protein Rationale: Troponin, homocysteine, and C-reactive protein are laboratory tests that may help provide clues to cardiovascular health and possible indicators for cardiac disease. Thyroid-stimulating hormone evaluates the thyroid, and blood urea nitrogen evaluates kidney function; these may not be pertinent initially to a focused cardiovascular assessment.

Which manifestation would the nurse expect in an elderly patient with arterial stiffening? 1. Widened pulse pressure 2. Decreased venous tortuosity 3. Decreased systolic BP 4. Thinning of the intima of the arteries

1. Widened pulse pressure Rationale: Arterial stiffening in the elderly patient results in loss of arterial compliance and increases pulse wave velocity, resulting in widened pulse pressure. The presence of inflamed, painful, or cordlike varicosities indicates increased venous tortuosity. Arterial stiffening can result in increased systolic BP. Arterial stiffening is caused by a loss of elastin in arterial walls and subsequent thickening of the intima of the arteries.

A patient who is wheelchair-bound is scheduled for a multigated acquisition (MUGA) scan to aid in the diagnosis of coronary artery disease (CAD). Which revisions in the test procedure will the nurse anticipate? 1. Vital signs will be monitored more frequently. 2. Adenosine will be administered IV. 3. The degree of incline on the treadmill will be lower. 4. A 12-lead electrocardiogram (ECG) will be performed.

2. Adenosine will be administered IV. Rationale: A MUGA scan is a common nuclear imaging test for heart wall motion during systole and diastole. Because the patient is unable to exercise, IV adenosine (Adenocard) will be given to dilate the coronary arteries and simulate the effect of exercise. The nurse will monitor vital signs, but this is not the priority action at this time. The patient will not be prepared for the treadmill because he or she is unable to exercise. A 12-lead ECG is not performed as part of the MUGA scan.

The nurse identifies a U wave on a patient's electrocardiogram. Which dietary instruction will be beneficial to the patient? 1. Use raw coconut oil for cooking. 2. Increase consumption of bananas. 3. Increase consumption of milk products. 4. Increase consumption of foods with omega-3 oils.

2. Increase consumption of bananas. Rationale: The presence of a U wave in the patient's electrocardiogram may indicate hypokalemia or repolarization of the Purkinje fibers. Hypokalemia can be caused by excessive sweating, diarrhea, or excessive laxative use. Bananas are a rich source of potassium. Therefore increasing the consumption of bananas will be beneficial for the patient. Coconut oil increases digestion and bowel function. Raw and virgin coconut oil have a laxative effect and should not be recommended. Milk and milk products like cheese are rich in sodium but not in potassium. Omega-3 oils help flush toxins out of the body. Therefore increasing the consumption of omega-3 oils would produce a laxative effect in the patient and potentiate hypokalemia.

Which finding on an older adult's electrocardiogram indicates cellular aging and fibrosis of the conduction system? 1. Regular cardiac rhythm 2. Lengthened QT intervals 3. Increased amplitude of QRS complex 4. Shortened PR interval and shortened QRS complex

2. Lengthened QT intervals Rationale: Lengthened QT intervals in an elderly patient's electrocardiogram indicate cellular aging and fibrosis of the conduction system. The patient with cellular aging and fibrosis of the conduction system is characterized by irregular cardiac rhythms, lengthened PR and QRS complex, and a decreased amplitude of the QRS complex.

A nurse is preparing a patient for a transesophageal echocardiogram (TEE). Which intervention would the nurse perform? 1. Inform the patient that skin irritation is likely. 2. Remove dentures and place a bite block in the mouth. 3. Provide lead shielding to areas that are exposed to radiation. 4. Provide information about risks associated with general anesthesia

2. Remove dentures and place a bite block in the mouth. Rationale: While preparing a patient for a TEE, the nurse asks the patient to remove the dentures and places a bite block in the mouth. This is done because an ultrasound transducer will need to be swallowed and passed through the esophagus. When preparing the patient for a chest x-ray, the nurse provides lead shielding to areas that are exposed to radiation. If the patient is undergoing ambulatory ECG, then the nurse asks the patient to carefully observe possible symptoms of skin irritation. The patient will receive IV sedation; general anesthesia is not used for the procedure.

Which action does the T wave in a patient's electrocardiogram (ECG) represent? 1. Depolarization of the atria 2. Repolarization of the ventricles 3. Repolarization of the Purkinje fibers 4. Delayed repolarization in hypokalemia

2. Repolarization of the ventricles Rationale: On an ECG, the T wave represents repolarization of the ventricles. Depolarization of the atria is represented by the P wave. The U wave, if present, can represent either repolarization of the Purkinje fibers or hypokalemia.

Which artery supplies the atrioventricular (AV) node and the bundle of His in most people? 1. Circumflex artery 2. Right coronary artery 3. Left main coronary artery 4. Left anterior descending artery

2. Right coronary artery Rationale: The right coronary artery supplies blood to the bundle of His and the AV node in the heart for 90% of the population, and a blockage of this artery can affect the blood supply to the bundle of His. The circumflex artery, left main coronary artery, and left anterior descending artery do not supply blood to the bundle of His.

The patient reports being confused about how there can be a blockage in the left anterior descending artery (LAD) although there is damage to the right ventricle. Which explanation would the nurse give? 1. "The LAD blood vessel supplies all of the blood to both ventricles." 2. "The left ventricle is supplied primarily by the right coronary artery." 3. "The LAD supplies blood to the left side of the heart and part of the right ventricle." 4. "It is actually on your right side of the heart, but we call it the left anterior descending vessel."

3. "The LAD supplies blood to the left side of the heart and part of the right ventricle." Rationale: The lower portion of the right ventricle receives blood flow from the left anterior descending artery as well as the right coronary artery during diastole. Both ventricles are not completely supplied by the same vessel because there are three major vessels supplying the two ventricles. The left ventricle is supplied primarily by the LAD and circumflex arteries. The LAD is on the left side of the heart.

Which condition would increase the friction between the heart layers and manifest as a friction rub? 1. An atrial myocardium thinner than the ventricle 2. Different thicknesses in the walls of each chamber 3. 5 mL of fluid in the space between the pericardial layers 4. 12 mL of fluid in the space between the pericardial layers

3. 5 mL of fluid in the space between the pericardial layers Rationale: Pericardial fluid between the pericardial layers prevents friction between the layers as the heart contracts. Approximately 10 to 15 mL of pericardial fluid is sufficient to reduce the friction. Therefore 5 mL of pericardial fluid indicates that the patient experiences greater friction between the pericardial layers. If the atrial myocardium is thinner than the ventricle, it indicates normal heart anatomy. The wall of each chamber of a normal heart is a different thickness; it does not cause greater friction. Pericardial fluid of 12 mL is a normal finding and does not indicate friction between the pericardial layers.

Which assessment finding would the nurse expect for a patient with ventricular hypertrophy? 1. Hypotension 2. Increased cardiac output 3. Cardiac output of 4 L/min/m2 4. Increased size of the heart chambers

3. Cardiac output of 4 L/min/m2 Rationale: The patient with ventricular hypertrophy has an enlargement of the heart muscle without an increase in cardiac output (CO) or the size of the chambers. The normal CO is 2.8 to 4.2 L/min/m2. The patient experiences elevated BP, not hypotension. If the arterial BP is elevated, the ventricles meet increased resistance to the ejection of blood, thus increasing the work demand of the heart, causing the muscles of the heart to enlarge. The enlargement occurs in the walls without an increase in the size of the chambers.

Which part of the heart's beat is represented by the QRS complex on a patient's electrocardiogram (ECG)? 1. Depolarization of the atria 2. Repolarization of the ventricles 3. Depolarization from the atrioventricular (AV) node through the ventricles 4. The length of time for the impulse to travel from the atria to the ventricles

3. Depolarization from the atrioventricular (AV) node through the ventricles Rationale: The QRS recorded on the ECG represents depolarization from the AV node throughout the ventricles. The P wave represents depolarization of the atria. The T wave represents repolarization of the ventricles. The interval between the PR and QRS represents the length of time it takes for the impulse to travel from the atria to the ventricles.

Which action does the QRS complex represent in an electrocardiogram? 1. Depolarization of the atria 2. Repolarization of the ventricles 3. Depolarization of both ventricles 4. Repolarization of the Purkinje fibers

3. Depolarization of both ventricles Rationale: An electrocardiogram is commonly used to detect abnormal heart rhythms and to investigate the cause of chest pain. The time taken for depolarization of both the ventricles is represented by the QRS interval. Depolarization of the atria is represented by the P wave. The T wave in the electrocardiogram should be upright, and it represents the time for ventricular repolarization. If present, the U wave indicates the repolarization of the Purkinje fibers.

Which structure initiates the action potential in the heart? 1. Bundle of His 2. Purkinje fibers 3. Sinoatrial node 4. Left bundle branch

3. Sinoatrial node Rationale: The sinoatrial node is called the pacemaker of the heart, and it initiates the electrical impulse, or action potential, in the heart. By way of the Purkinje fibers, the action potential moves through the walls of ventricles, but it is not initiated at this point. The action potential moves from the atrioventricular node through the bundle of His and the right and left bundle branches, but it is not initiated at these points.

Which statement describes cardiac reserve? 1. The amount of blood pumped by each cardiac ventricle in one minute 2. The peripheral resistance against which the left ventricle must pump 3. The ability to respond to health and illness demands by altering cardiac output 4. The amount of blood in the ventricles at the end of diastole, before the next contraction

3. The ability to respond to health and illness demands by altering cardiac output Rationale: The ability of the cardiovascular system to alter cardiac output in response to numerous situations in health and illness, such as stress, hypervolemia, and exercise, is known as cardiac reserve. The amount of blood pumped by each ventricle in one minute is called cardiac output. Afterload is the peripheral resistance against which the left ventricle must pump. Preload is the amount of blood in the ventricles at the end of diastole, before the next contraction.

Which physiologic change of aging increases the risk of a 75-year-old patient experiencing a sinus dysrhythmia? 1. Decreased pulse pressure 2. Decreased systolic BP (SBP) 3. Decreased resting supine heart rate (HR) 4. Decreased number of pacemaker cells in the SA node

4. Decreased number of pacemaker cells in the SA node Rationale: The number of pacemaker cells in the SA node decreases with age. By age 75, a person may have only 10% of the normal number of pacemaker cells. Arterial and venous blood vessels thicken and become less elastic with age. Arteries increase their sensitivity to vasopressin (antidiuretic hormone). With aging, both of these changes contribute to a progressive increase in SBP and a decrease or no change in diastolic BP (DBP). Thus an increase in the pulse pressure is found. The resting supine HR is not markedly affected by age.

A patient's baseline heart rate is 85 beats/min. Which heart rate would indicate sympathetic nervous system stimulation in this patient? 1. Heart rate of 50 beats/min 2. Heart rate of 70 beats/min 3. Heart rate of 80 beats/min 4. Heart rate of 110 beats/min

4. Heart rate of 110 beats/min Rationale: Stimulation of the sympathetic nervous system increases heart rate. The normal heart rate is in the range of 60 to 100 beats/min. Therefore the patient with a heart rate of 110 beats/min has a stimulated sympathetic nervous system. Stimulation of the sympathetic nervous system does not decrease the patient's heart rate. Therefore the heart rate of 50 beats/min does not indicate stimulation of the patient's sympathetic nervous system. The heart rates of 70 and 80 beats/min are normal findings and do not indicate stimulation of the patients' sympathetic nervous systems.

A nurse is reviewing a patient's laboratory results: blood cholesterol level of 350 mg/dL, homocysteine level of 14 µmol/L, b-type natriuretic peptide (BNP) of 90 pg/mL, cardiac troponin I (cTnI) level of 0.3 ng/mL, myoglobin level of 16 mcg/L, and C-reactive protein of 4 mg/L. Which interpretation would the nurse reach from these laboratory results? 1. Heart failure 2. Pulmonary complications 3. Myocardial infarction (MI) 4. High risk of cardiac disease

4. High risk of cardiac disease Rationale: The patient has a high risk of developing cardiovascular disease, as evidenced by the high cholesterol levels, the homocysteine levels, and the C-reactive protein level. High cholesterol levels directly impact the heart and the blood vessels. A high homocysteine level indicates amino acid production during protein catabolism. It can harm the endothelium. C-reactive protein is a marker of inflammation, and a level of 4 mg/L indicates a high risk of cardiac disease. A normal level of BNP also rules out pulmonary complications. The BNP level is normal, thus ruling out heart failure. The patient has normal levels of troponin and myoglobin, which are indicators of myocardial injury; therefore the patient has not had an MI.

The registered nurse observes another health care provider performing a cardiac assessment on a patient. Which activity by the health care provider would the nurse question? 1. Documents a normal peripheral pulse as 2+ 2. Identifies that a capillary refill of three seconds is abnormal 3. Uses the diaphragm of the stethoscope to auscultate for S1 and S2 heart sounds 4. Inspects the neck veins while swiftly moving the patient from supine to upright

4. Inspects the neck veins while swiftly moving the patient from supine to upright Rationale: To assess for jugular vein distention, the health care provider should inspect the large veins in the neck while the patient is gradually moved from a supine position to an upright (30- to 45-degree position). The patient should not be repositioned too quickly. When a normal peripheral pulse is a normal force, it should be documented as 2+. A capillary refill should occur in less than two seconds with normal tissue perfusion and cardiac output (CO). S1 and S2 are heard best with the diaphragm of the stethoscope because they are high-pitched sounds.

Which term would the nurse use to document a patient's report of awakening during the night with sudden shortness of breath? 1. Orthopnea 2. Atrial fibrillation 3. Intermittent claudication 4. Paroxysmal nocturnal dyspnea

4. Paroxysmal nocturnal dyspnea Rationale: Paroxysmal nocturnal dyspnea is defined as attacks of shortness of breath, especially at night, which awaken the patient. Orthopnea is the need to sleep in an upright position. Intermittent claudication affects the muscles of the leg during exercise related to decreased oxygen delivery to the muscle. Atrial fibrillation is a conduction abnormality of the heart.