Cardiac quizzlet Flashcards
During which interval on the EKG does the aortic valve close?
T-wave
Which one of the following is the best index of preload?
Left ventricular end-diastolic volume
Which one of the following is the best index of afterload?
Left ventricular mean systolic pressure
The highest blood flow per gram of left ventricular myocardium would occur
At the beginning of diastole
During ventricular ejection, the pressure difference smallest in magnitude is between the
Left ventricle and aorta
Which of the following would result from a regurgitant aortic valve in a nonfailing heart?
A decrease in diastolic pressure
Stroke volume is increased by
A decrease in venous compliance
An increased preload would most likely be caused by an increase in
Venous tone
Propagation of the action potential through the heart is fastest in the
Purkinje fibers
A patient in heart failure improves markedly after using a drug that increases the inotropic state of her heart. Which one of the following changes is primarily responsible for the improvement in her condition?
A reduction in heart size
Closure of the aortic valve occurs at the onset of which phase of the cardiac cycle?
Isovolumetric relaxation
Which one of the following is most likely to be observed in a patient with untreated atrial fibrillation?
An increased left atrial pressure
Normal splitting of the second heart sound (S2) into two components is increased during inspiration because
The closing of the pulmonic valve is delayed
Which of the following statements about the third heart sound (S3) is correct?
It is produced by turbulence during rapid ventricular filling in early diastole
In a resting, healthy man, the ejection fraction is approximately?
0.6
Sustained elevation of cardiac output will occur with which of the following conditions?
Anemia
A diastolic murmur accompanied by an increased preload can be caused by
Aortic regurgitation
Increasing vagal stimulation of the heart will cause an increase in
PR interval
During exercise, there is an increase in a person’s
Stroke volume
Phase-4 depolarization of SA nodal cells is caused by
An increase in the flow of sodium into the cell
Cardiovascular changes that occur during inspiration include decreased
Systemic blood pressure
Blood pressure increases and heart rate decreases in response to
Increased intracranial pressure
During exercise, cardiac output is augmented by
Increased ventricular contractility
When flow through the mitral valve is restricted by mitral stenosis,
Exercise can induce acute pulmonary edema
Stroke volume can be decreased by
Increasing heart rate
An ectopic extrasystole caused by a ventricular focus is characterized by
A skipped ventricular contraction
The electrocardiogram is most effective in detecting a decrease in
Coronary blood flow
Stroke volume can be increased by
Decreasing total peripheral resistance
Which one of the following will be observed in a patient with a dilated failing left ventricle and a normal resting mean blood pressure?
An increased pulmonary capillary hydrostatic pressure
Which one of the following correctly describes an event that normally occurs during the PR interval?
The cardiac action potential passes through the AV node
Left ventricular wall stress will be decreased by an increase in
The thickness of the free wall of the left ventricle
Which one of the following will be observed in a patient with aortic regurgitation?
An increased ejection fraction
At which point on the above ventricular action potential is membrane potential most dependent on calcium permeability?
Point D
During which interval on the ECG does the bundle of His depolarize?
PR
The diagnosis of a first-degree heart block is made if
The PR interval of the ECG is increased
Positive inotropic drugs such a digitalis reduce ischemic cardiac pain (angina) in a dilated failing heart by
Decreasing preload
The mitral valve opens at point
A
The second heart sound begins at point
B
Systole begins at point
E
A major sign of cardiac tamponade is
Pulsus paradoxus
A mild hemorrhage will cause stroke volume to shift from point X to point
A
An increase in afterload and venous compliance can cause stroke volume to change from the point marked X to point
C
The upstroke of the SA nodal action potential is produced by opening a channel that is
Primarily permeable to Na+
The channel responsible for the initiation of phase-4 depolarization in SA nodal cells
Is primarily permeable to Na+
Sympathetic stimulation of the heart results in
An increase in the activity of the SR calcium pump
An exercise stress test to rule out ischemic heart disease is positive if
The ST segment of the ECG is depressed
A 42-year-old woman with mitral prolapse is admitted to the hospital for evaluation of her cardiac function. Which of the following values is the best index of the preload on her heart?
Left ventricular end-diastolic volume
A patient presents to the Emergency Department with intermittent chest pain. The ECG and blood tests are negative for myocardial infarction, but the echocardiogram shows thickening of the left ventricular muscle and narrowing of the aortic valve. Medications to lower afterload are prescribed. Which of the following values would provide the best measure of the effectiveness of the medication in lowering left ventricular afterload in this patient?
Left ventricular mean systolic pressure
A 55-year-old male reports several recent episodes of syncope. An electrocardiogram is performed. Which of the following arrhythmias is most commonly associated with syncope?
Third-degree heart block
The spouse of a 58-year-old-man calls 9-1-1 because her husband complains of chest pain radiating down his left arm. He is transported to the Emergency Department, where an electrocardiogram and cardiac enzymes indicate a recent myocardial infarction. The man is sent for a cardiac catheterization, including coronary angiography and hemodynamic recordings throughout the cardiac cycle. No valvular defects were present. During ventricular ejection, the pressure difference smallest in magnitude is between which of the following?
Left ventricle and aorta
An 82-year-old woman was admitted to the hospital with ascites, peripheral edema, and shortness of breath. Cardiac catheterization was ordered and the following values were obtained:
Pulmonary artery O2 content = 20 mL/100 mL
Pulmonary vein O2 content = 12 mL/100 mL
Oxygen consumption = 280 mL/min
Stroke volume = 40 mL
What is the woman’s cardiac output?
3.5 L/min
A 66-year-old male is referred to a cardiologist for evaluation. Physical examination reveals a diastolic murmur prominent over the left sternal border, a decrease in diastolic pressure, and an increase in pulse pressure. Which of the following is the most likely diagnosis?
Aortic regurgitation
A patient undergoes cardiac transplantation for severe idiopathic cardiomyopathy. Upon release from the hospital, the patient is referred to a cardiac rehabilitation program. The exercise technologist starts the patient on a walking regimen. In transplant patients, stroke volume may increase during exercise by which of the following mechanisms?
A decrease in venous compliance
A patient complaining of an irregular heart beat is referred for a cardiac electrophysiological (EP) study. Propagation of the action potential through the heart is fastest in which of the following?
Purkinje fibers
A 75-year-old woman presents with fatigue, edema, and shortness of breath. Her physician prescribes a diuretic and a positive inotropic agent. Which of the following changes is primarily responsible for the improvement in her condition?
A reduction in heart size
A 37-year-old woman undergoes a CT scan of the abdomen, which reveals a large peritoneal mass. A subsequent magnetic resonance angiography study showed that the abdominal aorta was constricted to one-half of its resting diameter. As a result, resistance to blood flow through the vessel would be which of the following?
Increased 16-fold
A 52-year-old man presents with tar-black stools. An endoscopy is ordered and reveals a bleeding ulcer in the antrum of the stomach. Baroreflex-induced compensation for the mild hemorrhage will cause which of the following values to be lower than it was before the hemorrhage?
Venous capacitance
A 22-year-old woman is hospitalized with a history of respiratory distress, fever, and fatigue. ST segment and T wave abnormalities suggest myocarditis, which is attributed to an acute viral origin. Over the next several days, significant peripheral edema develops. The edema is most likely caused by which of the following?
Increased central venous pressure
A patient undergoes cardiac catheterization to assess his left ventricular function prior to thoracic surgery. What is his ejection fraction, as determined from the left ventricular pressure-volume curve illustrated below.
0.54
A 38-year-old man has a murmur that ceases with the onset of the second heart sound. The second heart sound occurs at the onset of which phase of the cardiac cycle?
Isovolumetric relaxation
A 58-year-old woman with idiopathic pulmonary hypertension presents with right ventricular hypertrophy and cor pulmonale. Her electrocardiogram shows positive QRS complexes in leads V1, III, and aVF, and equiphasic QRS complexes in lead aVR. Which of the following is her mean QRS
+120°
A 57-year-old male complains of an irregular heart beat that he notices is relieved by pressing on his eyeball. An electrocardiogram reveals atrial fibrillation. Which of the following is most likely to accompany this condition?
An increased left atrial pressure
A 24-year-old woman undergoes an annual physical examination for participation on the varsity track team at her college. While auscultating her heart sounds, the sports medicine physician instructs the woman to take in a deep inspiration. During this maneuver, he detects splitting of the second heart sound. Which of the following is the mechanism underlying this finding?
Delayed closing of the pulmonic valve
A 55-year-old female presents for her annual physical examination. Upon auscultation, a third heart sound is heard. The differential diagnosis of this finding includes which of the following?
Anemia
A 23-year-old female presents with fatigue and is found to have a systolic murmur and higher than normal cardiac output. The differential diagnosis based on these findings includes which of the following?
Anemia
Ventricular pressure-volume curves are determined in two different patients, as illustrated below. Which of the following is greater in Patient #1?
Cardiac efficiency
Physical examination of a 41-year-old narcotic abusor reveals an early systolic murmur. The physician also notes a 7-cm distance between the height of the blood in his right internal jugular vein and sternal angle (normal = 3 cm). Which of the following conditions is most likely responsible for the physical findings?
Tricuspid regurgitation
A 42-year-old woman with lightheadedness and recurrent syncope is taken to the emergency department where she is given atropine. Her symptoms are relieved by an increase in which of the following?
Heart rate
A 32-year-old female complains of intermittent chest discomfort that occurs most frequently when she drinks lots of coffee to stay up to meet deadlines at work. She is referred to cardiology for an exercise stress test to rule out cardiac ischemia as the cause for her angina. The test will be considered positive if which of the following occurs?
ST segment depression occurs
A postlaminectomy patient suddenly stands up after being supine for 8 hours. As a result, which of the following hemodynamic variables will increase?
Ejection fraction
A newborn baby is cyanotic upon delivery. The cyanosis is not relieved by breathing 100% oxygen. A diagnosis of persistent fetal circulation is made based on which of the following clinical signs?
Pulmonary vasoconstriction and hypertension
A 19-year-old male severs an artery in a motorcycle accident. A bystander applies a tourniquet to stop the bleeding. When the paramedics arrive, the blood pressure of the injured man was only slightly hypotensive and his pupils were reactive. The greatest percentage of the redistributed blood volume came from which of the following?
Venules and veins
An 84-year-old woman presents with paroxysmal dizziness, syncope, confusion, and fatigue. Her heart rate did not change when the patient was instructed to perform a Valsalva maneuver. 24-hour Holter monitoring revealed periodic episodes of sinus bradycardia. Phase-4 depolarization of SA nodal cells is caused by which of the following?
An increase in the flow of sodium into the cell
During auscultation of a patient with long-standing hypertension, the physician notes that the splitting of the second heart sound is reversed with P2 occurring before A2. Which of the following is a common electrocardiographic finding accompanying paradoxical splitting of the second heart sound?
Left bundle branch block
An 83-year-old woman with long-standing hypertension presents after a near-syncopal episode upon standing. Her blood pressure is taken sitting and then standing. Systolic pressure decreased slightly and pulse pressure increased in the standing position. Which of the following can lead to an increased pulse pressure?
A decrease in aortic compliance
A 75-year-old woman makes an appointment to see her physician because she is having breathing difficulties when she lies down at night. An S3 gallop is heard upon auscultation. Her signs and symptoms are most likely due to which of the following?
Left heart failure
A cardiac catheterization is performed on a 39-year-old man who presents with angina. The left ventricular pressure-volume curve shows a decreased stroke volume and ejection fraction. Which of the following mechanisms may compromise stroke volume following myocardial infarction?
An increase in heart rate
A 42-year-old athlete becomes alarmed when he notices a series of heart palpitations several hours after he exercises. After examining the patient’s ECG, the physician notes a sinus rhythm with occasional PVCs (premature ventricular complexes). The physician tells his patient that the palpitations are due to interpolated beats and that they are not a cause for alarm. Benign PVCs may occur because the athlete has which of the following?
Bradycardia
A 56-year-old male was admitted to the hospital with angina and diaphoresis. A myocardial infarction is suspected, and a 12-lead electrocardiogram (ECG) is ordered. The ECG is most effective in detecting a decrease in which of the following?
Coronary blood flow
A 48-year-old sedentary, obese male with four-vessel coronary occlusive disease has a massive myocardial infarction while shoveling snow. In the blizzard conditions, it takes the ambulance over an hour to reach the man’s home. When the paramedics arrive, the patient’s radial pulse is rapid and thready, he has pink froth coming from his mouth, and he is nonresponsive. Increasing which of the following would lead to an increased stroke volume in cardiogenic shock?
Ventricular contractility
A patient comes to his physician complaining that he is no longer able to exercise as long as he used to. The physician auscultates crepitant rales and a third heart sound; blood pressure is normal. He sends the patient to cardiology to rule out heart failure. Which of the following is most consistent with a diagnosis of left heart failure?
An increased left ventricular wall stress
A pacemaker is inserted in a patient in order to shorten the PR interval detected on their ECG. Which of the following events normally occurs during the PR interval?
The cardiac action potential passes through the AV node
A 47-year-old female is brought to the Emergency Department because she fainted at the gym during her daily aerobic workout. A prominent systolic murmur is heard and a presumptive diagnosis of aortic stenosis is made. Which of the following is consistent with that diagnosis?
A decreased pulse pressure
A patient with an inferior MI develops a stable bradycardia of 50/min. The cardiologist orders an ECG to evaluate whether there is sinus node dysfunction or an atrioventricular conduction disturbance. The diagnosis of a first-degree heart block is made in which of the following cases?
The PR interval of the ECG is increased
A 67-year-old man who has difficulty breathing when he exercises makes an appointment to see his physician. Auscultation reveals a holosystolic murmur leading to the diagnosis of mitral regurgitation. Which of the following laboratory findings is most likely to be present?
An increased a wave
A 43-year-old male comes to his physician complaining of exhaustion and shortness of breath. After completing the physical exam, the physician suspects the patient may be suffering from cardiac tamponade. Which of the following observations led to the physician’s putative diagnosis?
Pulsus paradoxus
An EMT arrives at the scene of an automobile accident, and finds a hemorrhaging, unconscious young woman. Which of the following is a sign of hemorrhagic shock?
Low hematocrit
A 37-year-old patient is brought to the Emergency Department in shock. Which of the following is a reason to direct treatment toward anaphylactic shock rather than hypovolumic shock?
Cardiac output is higher than normal
A woman with syndrome X is prescribed a low-calorie diet and 30-min of daily aerobic exercise. Sympathetic stimulation during exercise has which of the following cardiac effects?
An increase in the activity of the SR calcium pump
A 23-year-old collegiate dance squad member adopts a sedentary lifestyle once she starts medical school. After the Gross Anatomy course, she decides to restore her state of physical fitness by resuming a regular exercise routine. The cardiovascular responses to isotonic exercise include an increase in which of the following?
Stroke volume
A 2-year-old boy is mauled by a black bear while hiking with his family in the Appalachian mountains. A claw puncture wound to the skull compressed the underlying brain tissue. Which of the following occurs in response to an increased intracranial pressure?
Blood pressure increases and heart rate decreases
Left ventricular wall stress will be decreased by an increase in which of the following?
The thickness of the free wall of the left ventricle
A 48-year-old man develops chest pain while running. His wife takes him to the Emergency Department, where the following ECG is obtained. The electrocardiographic changes are consistent with a diagnosis of which of the following?
Anterior infarction
A patient with Type II diabetes reports for his 6-month check-up. His doctor prescribes a daily 30-minute routine of walking at a brisk pace. During aerobic exercise, blood flow remains relatively constant within which of the following?
Brain
A 56-year-old man presents with complaints of fatigue and headaches. During the physical examination, he is found to have a wide pulse pressure. Which of the following conditions causes pulse pressure to increase?
Hypertension
A 22-year-old male ruptures his spleen in a motorcycle accident. A reduction in blood pressure would cause a decrease in which of the following?
Venous compliance
Which of the following organs has the highest arteriovenous O2 difference under normal resting conditions?
Heart
A 63-year-old woman with congestive heart failure is given digitalis. Positive inotropic drugs can reduce ischemic cardiac pain (angina) in a dilated failing heart by doing which of the following?
Decreasing preload
Which of the following characteristics is most similar in the systemic and pulmonary circulations?
Preload
A 6-year-old girl undergoes a routine physical examination for entry into the first grade. She is found to be tachycardic, and has a wide pulse pressure. A thrill and a continuous murmur with late systolic accentuation at the upper left sternal edge are detected upon auscultation. Echocardiography reveals a patent ductus arteriosus. Which of the following best describes the function of the ductus arteriosus in the fetal circulation?
It diverts oxygenated blood away from the lungs to the aorta
A 63-year-old woman presented with acute onset of right eye pain. Ophthalmic and neurologic examinations were normal except for a loud right carotid bruit. The eye pain ceased following carotid endarterectomy. The bruit was most likely caused by which of the following?
A high velocity of blood within the carotid artery
A 57-year-old woman is undergoing a femoral popliteal bypass for her peripheral vascular disease. The vascular surgeon wishes to induce a localized arteriolar constriction to help control hemostasis. An increase in the local concentration of which of the following agents will cause systemic vasoconstriction?
Angiotensin II
Which of the following is true regarding the functional closure of the ductus arteriosus?
It is the final event required for conversion of the transitional circulation in the newborn to the adult circulatory pattern
At which of the following sites in the cardiovascular system does the blood flow lose the greatest amount of energy?
Arterioles
During the cardiac cycle, when does the highest coronary blood flow per gram of left ventricular myocardium occur.
At the beginning of diastole
A 59-year-old male with an ejection fraction of 15%,who is being treated with medications for his heart failure, is asked whether he would like to participate in a trial for an experimental drug. The drug being tested is designed to decrease the expression of phospholamban on ventricular muscle cells. Which of the following would be increased by decreasing phospholamban?
The concentration of calcium within the SR
A 29-year-old woman presents at the obstetrician/gynecologist’s office with breast tenderness. She’s concerned she may have a lump because her mother had breast cancer, and reports that she can’t be pregnant because she just finished her menstrual period about 2 weeks ago. An assay for human chorionic gonadotropin (hCG) in her urine is positive, confirming pregnancy. In the developing fetus, which vessel has the greatest partial pressure of oxygen?
Umbilical vein
