Deck 33: Disorders of Renal Function

Question 1

A physician has ordered the measurement of a cardiac patient's electrolyte levels as part of the client's morning blood work. Which of the following statements best captures the importance of potassium in the normal electrical function of the patient's heart?

A) Potassium catalyzes the metabolism of ATP, producing the gradient that results in electrical stimulation.
B) Potassium is central to establishing and maintaining the resting membrane potential of cardiac muscle cells.
C) The impermeability of cardiac cell membranes to potassium allows for action potentials achieved by the flow of sodium ions.
D) The reciprocal movement of one potassium ion for one sodium ion across the cell membrane results in the production of an action potential.

Answer 1

Potassium is central to establishing and maintaining the resting membrane potential of cardiac muscle cells.

Question 2

Which of the following statements describes phase 4 of the action potential of cells in the sinoatrial (SA) node?

A) A slow depolarization occurs when Na⁺ is transported out of the cell and K⁺ moves back in, resulting in resting membrane potential.
B) The cells are capable of responding to a greater than normal stimulus before the resting membrane potential is reached.
C) The fast sodium channels in the cellular membranes close, causing an abrupt decrease in intracellular positivity.
D) Potassium permeability is allowing the cell membrane to remain depolarized, and Ca²⁺ channel opens moving Ca²⁺ back into the cell.

Answer 2

A slow depolarization occurs when Na⁺ is transported out of the cell and K⁺ moves back in, resulting in resting membrane potential.

Question 3

An ECG technician is placing leads on a patient who has presented to the emergency department with a sudden onset of chest pain. The technician would recognize which of the following facts about the placement of leads and the achievement of a clinically accurate ECG?

A) The electrical potential recorded by a lead on an extremity will vary significantly depending on where the lead is placed on the extremity.
B) The chest leads measure electrical activity on the horizontal plane, while limb leads measure it on the vertical plane.
C) Limb leads measure the electrical activity of the heart indirectly through the activity of adjacent skeletal muscle.
D) A total of 12 chest leads are necessary to attain the most accurate ECG.

Answer 3

The chest leads measure electrical activity on the horizontal plane, while limb leads measure it on the vertical plane.

Question 4

The cardiologist just informed a patient that he has a reentry circuit in the electrical conduction system in his heart. This arrhythmia is called Wolff-Parkinson-White (WPW) syndrome. After the physician has left the room, the patient asks the nurse to explain this to him. Which of the following statements most accurately describes what is happening?

A) "This means that the SA node (which is the beginning of your heart's electrical system) has been damaged and is no longer functioning normal."
B) "You must have a large clot in one of your arteries that supply oxygenated blood to the special conduction cells in your heart."
C) "There is an extra, abnormal electrical pathway in the heart that leads to impulses traveling around the heart very quickly, in a circular pattern, causing the heart to beat too fast."
D) "For some reason, your electrical system is not on full charge, so they will have to put in new leads and a pacemaker to make it work better."

Question 5

A 68-year-old male complains to his family physician that when he tests his blood pressure using a machine at his pharmacy, his heart rate is nearly always very low. At other times, he feels that his heart is racing, and it also seems to pause at times. The man has also had occasionally light-headedness and a recent syncopal episode. What is this client's most likely diagnosis and the phenomenon underlying it?

A) Sick sinus syndrome as a result of a disease of his sinus node and atrial or junctional arrhythmias
B) Ventricular arrhythmia as a result of alternating vagal and sympathetic stimulation
C) Torsade de pointes as a result of disease of the bundle of His
D) Premature atrial contractions that vacillate between tachycardic and bradycardic episodes as a consequence of an infectious process

Question 6

A 6-year-old boy has been brought to the emergency department by ambulance after his mother discovered that his heart rate was "so fast I couldn't even count it." The child was determined to be in atrial flutter, and his mother is seeking an explanation from the health care team. Which of the following points should underlie an explanation to the mother?

A) The child is experiencing a reentry rhythm in his right atrium.
B) The resolution of the problem is dependent on spontaneous recovery and is resistant to pacing interventions.
C) The child is likely to have a normal ECG apart from the rapid heart rate.
D) The boy's atria are experiencing abnormal sympathetic stimulation.

Question 7

A nurse educator is teaching a group of nurses at a long-term care facility about atrial fibrillation in light of its prevalence in older adults. Which of the following statements by the nurses would the educator most want to correct?

A) "The electrical impulses go in chaotic directions, and so the atria can't contract properly."
B) "An ECG of someone in atrial fibrillation would be almost random in appearance."
C) "The contraction of the ventricles and the atria can range from 400 to 600 beats/minute."
D) "It can be hard to measure at the bedside because not all ventricular beats make a palpable pulse."

Question 8

A medical student is working with a 61-year-old male client in the hospital who has presented with a new onset of atrial fibrillation. Which of the following courses of treatment will the student most likely expect the attending physician to initiate?

A) Immediate cardioversion followed by surgery to correct the atrial defect
B) Anticoagulants and beta-blockers to control rate
C) Antihypertensives and constant cardiac monitoring in a high acuity unit
D) Diuretics, total bed rest, and cardioversion if necessary

Question 9

A 63-year-old male client has been diagnosed with a bundle branch block. How will this client's care team most likely expect his condition to be expressed diagnostically?

A) His AV node will be performing the primary pacemaker role due to inadequacy of the SA node.
B) His ECG will show a flattened P wave as a result of impaired atrial depolarization.
C) Conduction from the Purkinje fibers to the bundle branches is compromised by inadequate conduction.
D) His ECG will show an inordinately wide QRS complex because impulses are bypassing the normal conduction tissue.

Question 10

Which of the following patients should the nurse be assessing for long QT syndrome?

A) A 95-year-old patient with Alzheimer's who is having periods of apnea
B) A 32-year-old male admitted for cocaine overdose with long history of illicit drug abuse
C) A 56-year-old female admitted for total hysterectomy due to excessive bleeding and clotting
D) A 68-year-old male who was in a car accident with sternal bruising and fractured femur

Question 11

A number of patients in an acute cardiac care unit of a hospital have diagnoses of impaired cardiac conduction. Which of the following patients is most deserving of immediate medical attention?

A) A 46-year-old man whose cardiac telemetry shows him to be in ventricular tachycardia
B) A 69-year-old woman who has entered ventricular fibrillation
C) A 60-year-old man with premature ventricular contractions (PVC) and a history of atrial fibrillation
D) A 60-year-old woman who has just been diagnosed with a first-degree AV block

Question 12

A 71-year-old man is slated for pacemaker insertion for treatment of a third-degree AV block. The man's nurse has been educating him about his diagnosis and treatment and answering the numerous questions he has about his health problem. Which of the following teaching points should the nurse include in this patient teaching?

A) "This is almost certainly a condition that you were actually born with, but that is just now becoming a serious problem."
B) "Because the normal electrical communication in lacking, the bottom parts of your heart are beating especially fast to compensate for inefficiency."
C) "The root problem is that the top chambers of your heart and the bottom chambers of your heart aren't coordinating to pump blood efficiently."
D) "If left untreated, this would have put you at great risk of stroke or heart attack."

Question 13

A 72-year-old woman with a recent onset of syncopal episodes has been referred to a cardiologist by her family physician. As part of the client's diagnostic workup, the cardiologist has ordered her to wear a Holter monitor for 24 hours. Which of the following statements best captures an aspect of Holter monitoring?

A) A Holter monitor is preferable to standard ECG due to its increased sensitivity to cardiac electrical activity.
B) The primary goal is to allow the cardiologist to accurately diagnose cardiomyopathies.
C) Accurate interpretation of the results requires correlating the findings with activity that the woman was doing at the time of recording.
D) Holter monitors are normally set to record electrical activity of the heart at least once per hour.

Question 14

A 31-year-old woman with a congenital heart defect reports episodes o light-headedness and syncope, with occasional palpitations. A resting electrocardiogram reveals sinus bradycardia, and she is suspected to have sick sinus syndrome. Which of the following diagnostic methods is the best choice to investigate the suspicion?

A) Signal-averaged ECG
B) Exercise stress testing
C) Electrophysiologic study
D) Holter monitoring

Question 15

Following electrophysiological testing that included ablation therapy, the nurse should be assessing the patient for which complication that may occur postprocedure?

A) Complaints of nausea and spitting up bile-looking secretions along with stomach cramps
B) Sudden onset of dysonea, tachypnea, and chest pain of a "pleuritic" nature (worsened by breathing)
C) Bleeding from the nose that requires packing, excessive swallowing of mucus, and coughing
D) Complaints of heart palpitations, frequent PVCs noted on monitor, and substernal chest pain

Question 16

A nurse who provides care in a geriatric subacute medicine unit of a hospital has noted that a large number of patients receive $\beta$ -adrenergic blocking medications such as metoprolol. Which of the following statements best conveys an aspect of the use of beta-blockers?

A) They can be used to treat supraventricular arrhythmias and decrease automaticity by depressing phase 4 of the action potential.
B) They inhibit the potassium current and repolarization, extending the action potential and refractoriness.
C) They counteract arrhythmias and tachycardias by increasing vagal stimulation.
D) They decrease myocardial oxygen demand by blocking the release of intracellular calcium ions.

Question 17

A patient, who is experiencing some angina associated with atrial tachycardia, has been placed on verapamil (Calan), a calcium channel blocker. Knowing that this medication blocks the slow calcium channels, thereby depressing phase 4 and lengthening phases 1 and 2 action potential, the nurse should assess this patient for which of the following adverse reactions?

A) Bradycardia
B) Ventricular tachycardia
C) Sudden cardiac death
D) Increased cardiac output

Question 18

A 70-year-old woman with ongoing severe atrial fibrillation is scheduled for defibrillation. What is an aspect of the rationale and physiology of defibrillation treatment?

A) Interruption of disorganized impulses by the current allows the AV node to readopt its normal pacemaker role
B) Defibrillation can be achieved using either a transcutaneous or transvenous pacemaker.
C) Defibrillation must be coincided with the R wave of the ECG in order to be successful.
D) The goal is to depolarize the entire heart during the passage of current.

Question 19

A patient with a new automatic implantable cardioverter-defibrillator (AICD) asks the nurse what happens if he goes into that deadly heart rhythm again. The nurse will base her response knowing that the AICD will

A) periodically fire just to test for lead placement and battery life.
B) respond to ventricular tachyarrhythmia by delivering a shock within 10 to 20 seconds of its onset.
C) use radiofrequency energy to deliver an electrical shock through the site where the lethal rhythm originates.
D) remove scar tissue and aneurysm during placement of electrodes and then will shock if paradoxical ventricular movement is located.

Question 20

Assuming that they have not responded to drug therapy, which of the following clients is likely to be the best candidate for surgical cardiac ablation?

A) A 62-year-old woman with peripheral vascular disease who has experienced multiple episodes of torsade des pointes
B) A 75-year-old man with diabetes but no previous heart disease that suddenly develops syncope due to sick sinus syndrome
C) A 46-year-old man with unstable angina and a history of myocardial infarction who is found to have long QT syndrome and episodes of frequent ventricular arrhythmias
D) A 22-year-old woman with an atrial septal defect who has recurrent paroxysmal atrial flutter with rapid ventricular rate associated with her caffeine intake.