Chapter 35 - Dysrhythmias
30. When analyzing an electrocardiographic (ECG) rhythm strip of a patient with a regular heart rhythm, the nurse counts 30 small blocks from one R wave to the next. The nurse calculates the patient's heart rate as ____.
Answer: 50 Rationale: There are 1500 small blocks in a minute, and the nurse will divide 1500 by 30.
31. When preparing to defibrillate a patient, in which order will the nurse perform the following steps? (Put a comma and a space between each answer choice [A, B, C, D, E].) a. Turn the defibrillator on. b. Deliver the electrical charge. c. Select the appropriate energy level. d. Place the hands-free, multifunction defibrillator pads on the patient's chest. e. Check the location of other staff and call out "all clear."
Answer: A, C, D, E, B Rationale: This order will result in rapid defibrillation without endangering hospital staff.
16. A patient has ST segment changes that suggest an acute inferior wall myocardial infarction. Which lead would be the most useful for monitoring the patient? a. I b. II c. V2 d. V6
Answer: b. II Rationale: Leads II, III, and AVF reflect the inferior area of the heart and the ST segment changes. Lead II will best capture any electrocardiographic changes that indicate further damage to the myocardium. The other leads do not reflect the inferior part of the myocardial wall and will not provide data about further ischemic changes in that area.
12. Which action by a nurse caring for a patient after an implantable cardioverter-defibrillator (ICD) insertion indicates a need for more teaching about the care of patients with ICDs? a. The nurse administers amiodarone (Cordarone) to the patient. b. The nurse helps the patient fill out the application for obtaining a Medic Alert device. c. The nurse encourages the patient to do active range-of-motion exercises for all extremities. d. The nurse teaches the patient that sexual activity can be resumed when the incision is healed.
Answer: c. The nurse encourages the patient to do active range-of-motion exercises for all extremities. Rationale: The patient should avoid moving the arm on the ICD insertion site until healing has occurred to prevent displacement of the ICD leads. The other actions by the new nurse are appropriate for this patient.
2. The nurse needs to quickly estimate the heart rate for a patient with a regular heart rhythm. Which method will be fastest to use? a. Count the number of large squares in the R-R interval and divide by 300. b. Print a 1-minute electrocardiogram (ECG) strip and count the number of QRS complexes. c. Use the 3-second markers to count the number of QRS complexes in 6 seconds and multiply by 10. d. Calculate the number of small squares between one QRS complex and the next and divide into 1500.
Answer: c. Use the 3-second markers to count the number of QRS complexes in 6 seconds and multiply by 10. Rationale: Using the 3-second markers to count the number of QRS complexes in 6 seconds and multiplying by 10 is the quickest way to determine the ventricular rate for a patient with a regular rhythm. The other methods are accurate but take longer.
1. What should the nurse measure to determine whether there is a delay in impulse conduction through the patient's ventricles? a. P wave b. Q wave c. PR interval d. QRS complex
Answer: d. QRS complex Rationale: The QRS complex represents ventricular depolarization. The P wave represents the depolarization of the atria. The PR interval represents depolarization of the atria, atrioventricular node, bundle of His, bundle branches, and the Purkinje fibers. The Q wave is the first negative deflection following the P wave and should be narrow and short.
20. A patient develops sinus bradycardia at a rate of 32 beats/min, has a blood pressure (BP) of 80/42 mm Hg, and reports feeling faint. Which action should the nurse take? a. Reposition the patient on the left side. b. Have the patient perform the Valsalva maneuver. c. Give the scheduled dose of diltiazem (Cardizem). d. Apply the transcutaneous pacemaker (TCP) pads.
Answer: d. Apply the transcutaneous pacemaker (TCP) pads. Rationale: The patient is experiencing symptomatic bradycardia and treatment with TCP is appropriate. Calcium channel blockers will further decrease the heart rate and the diltiazem should be held. The Valsalva maneuver will further decrease the rate. Repositioning on the left side may decrease cardiac output and blood pressure further.
7. A patient who was admitted with a myocardial infarction has a 45-second episode of ventricular tachycardia, then converts to sinus rhythm with a heart rate of 98 beats/min. Which action should the nurse take next? a. Immediately notify the health care provider. b. Document the rhythm and continue to monitor the patient. c. Prepare for synchronized cardioversion per agency protocol. d. Prepare to give IV amiodarone per agency dysrhythmia protocol.
Answer: d. Prepare to give IV amiodarone per agency dysrhythmia protocol. Rationale: The burst of sustained ventricular tachycardia indicates that the patient has significant ventricular irritability, and antidysrhythmic medication administration is needed to prevent further episodes. The nurse should notify the health care provider after the medication is started. Cardioversion is not indicated given that the patient has returned to a sinus rhythm. Documentation and continued monitoring are not adequate responses to this situation.
15. Which finding from a newly admitted adult patient's electrocardiogram (ECG) requires further investigation by the nurse? a. Isoelectric ST segment. b. PR interval of 0.18 second. c. QT interval of 0.38 second. d. QRS interval of 0.14 second.
Answer: d. QRS interval of 0.14 second. Rationale: Because the normal QRS interval is less than 0.12 seconds, the patient's QRS interval of 0.14 seconds indicates that the conduction through the ventricular conduction system is prolonged. The PR interval and QT interval are within normal range and ST segment should be isoelectric (flat).
9. A patient with dilated cardiomyopathy has new onset atrial fibrillation that has been unresponsive to drug therapy for several days. What topic should the nurse plan to include in patient teaching? a. Anticoagulant therapy. b. Permanent pacemakers. c. Emergency cardioversion. d. IV adenosine (Adenocard).
Answer: a. Anticoagulant therapy Rationale: Atrial fibrillation therapy that has persisted for more than 48 hours requires anticoagulant treatment for 3 weeks before attempting cardioversion. This is done to prevent embolization of clots from the atria. Cardioversion may be done after several weeks of anticoagulation therapy. Adenosine is not used to treat atrial fibrillation. Pacemakers are routinely used for patients with bradydysrhythmias. Information does not indicate that the patient has a slow heart rate.
17. Which laboratory result for a patient with multifocal premature ventricular contractions (PVCs) is most important for the nurse to communicate to the health care provider? a. Blood glucose of 243 mg/dL. b. Serum chloride of 92 mEq/L. c. Serum sodium of 134 mEq/L. d. Serum potassium of 2.9 mEq/L.
Answer: d. Serum potassium of 2.9 mEq/L Rationale: Hypokalemia increases the risk for ventricular dysrhythmias such as PVCs, ventricular tachycardia, and ventricular fibrillation. The health care provider will need to prescribe a potassium infusion to correct this abnormality. Although the other laboratory values are also abnormal, they are not likely to be the cause of the patient's PVCs and do not require immediate correction.
4. The nurse obtains a rhythm strip on a patient who has had a myocardial infarction and makes the following analysis: no visible P waves, PR interval not measurable, ventricular rate of 162, R-R interval regular, QRS complex wide and distorted, and QRS duration of 0.18 second. How should the nurse interpret this cardiac rhythm? a. Atrial flutter. b. Sinus tachycardia. c. Ventricular fibrillation. d. Ventricular tachycardia.
Answer: d. Ventricular tachycardia Rationale: The absence of P waves, wide QRS, rate greater than 150 beats/min, and the regularity of the rhythm indicate ventricular tachycardia. Atrial flutter is usually regular, has a narrow QRS configuration, and has flutter waves present representing atrial activity. Sinus tachycardia has P waves. Ventricular fibrillation is irregular and does not have a consistent QRS duration.
5. A patient's heart monitor shows that every other beat is earlier than expected, has no visible P wave, and has a QRS complex that is wide and bizarre in shape. How will the nurse document the rhythm? a. Ventricular couplets. b. Ventricular bigeminy. c. Ventricular R-on-T phenomenon. d. Multifocal premature ventricular contractions.
Answer: b. Ventricular bigeminy Rationale: Ventricular bigeminy describes a rhythm in which every other QRS complex is wide and bizarre looking. Pairs of wide QRS complexes are described as ventricular couplets. There is no indication that the premature ventricular contractions are multifocal or that the R-on-T phenomenon is occurring.
11. The nurse evaluates that discharge teaching about the management of a new permanent pacemaker has been effective when the patient states a. "It will be several weeks before I can return to my usual activities." b. "I will avoid cooking with a microwave oven or being near one in use." c. "I will notify the airlines when I make a reservation that I have a pacemaker." d. "I won't lift the arm on the pacemaker side until I see the health care provider."
Answer: d. "I won't lift the arm on the pacemaker side until I see the health care provider." Rationale: The patient is instructed to avoid lifting the arm on the pacemaker side above the shoulder to avoid displacing the pacemaker leads. The patient should notify airport security about the presence of a pacemaker before going through the metal detector, but there is no need to notify the airlines when making a reservation. Microwave oven use does not affect the pacemaker. The insertion procedure involves minor surgery that will have a short recovery period.
22. The nurse has received change-of-shift report about the following patients on the progressive care unit. Which patient should the nurse see first? a. A patient with atrial fibrillation, rate 88 and irregular, who has a dose of warfarin (Coumadin) due. b. A patient with second-degree atrioventricular (AV) block, type 1, rate 60, who is dizzy when ambulating. c. A patient who is in a sinus rhythm, rate 98 and regular, recovering from an elective cardioversion 2 hours ago. d. A patient whose implantable cardioverter-defibrillator (ICD) fired twice today and has a dose of amiodarone (Cordarone) due.
Answer: d. A patient whose implantable cardioverter-defibrillator (ICD) fired twice today and has a dose of amiodarone (Cordarone) due. Rationale: The frequent firing of the ICD indicates that the patient's ventricles are very irritable. The priority is to assess the patient and give the amiodarone. The other patients can be seen after the amiodarone is given.
14. A 20-yr-old patient has a mandatory electrocardiogram (ECG) before participating on a college soccer team. The patient is found to have sinus bradycardia, rate 52 and blood pressure (BP) 114/54 mm Hg. The student denies any health problems. What action by the nurse is appropriate? a. Allow the student to participate on the soccer team. b. Refer the student to a cardiologist for further testing. c. Tell the student to stop playing immediately if any dyspnea occurs. d. Obtain more detailed information about the student's family health history.
Answer: a. Allow the student to participate on the soccer team. Rationale: In an aerobically trained individual, sinus bradycardia is normal. The student's normal BP and negative health history indicate that there is no need for a cardiology referral or for more detailed information about the family's health history. Dyspnea during an aerobic activity such as soccer is normal.
8. After the nurse gives IV atropine to a patient with symptomatic type 1, second-degree atrioventricular (AV) block, which finding indicates that the drug has been effective? a. Increase in the patient's heart rate. b. Increase in strength of peripheral pulses. c. Decrease in premature atrial contractions. d. Decrease in premature ventricular contractions.
Answer: a. Increase in the patient's heart rate. Rationale: Atropine will increase the heart rate and conduction through the AV node. Because the drug increases electrical conduction, not cardiac contractility, the quality of the peripheral pulses is not used to evaluate the drug effectiveness. The patient does not have premature atrial or ventricular contractions.
6. A patient has a sinus rhythm and a heart rate of 72 beats/min. The nurse determines that the PR interval is 0.24 seconds. What action should the nurse take? a. Notify the health care provider immediately. b. Document the finding and monitor the patient. c. Give atropine per agency dysrhythmia protocol. d. Prepare the patient for temporary pacemaker insertion.
Answer: b. Document the finding and monitor the patient. Rationale: First-degree atrioventricular block is asymptomatic and requires ongoing monitoring because it may progress to more serious forms of heart block. The rate is normal, so there is no indication that atropine is needed. Immediate notification of the health care provider about an asymptomatic rhythm is not necessary.
13. A patient with supraventricular tachycardia who is alert and has a blood pressure of 110/66 mm Hg is being prepared for cardioversion. Which action should the nurse take? a. Turn the synchronizer switch to the "off" position. b. Give a sedative before cardioversion is implemented. c. Set the defibrillator/cardioverter energy to 360 joules. d. Provide assisted ventilations with a bag-valve-mask device.
Answer: b. Give a sedative before cardioversion is implemented. Rationale: When a patient has a nonemergency cardioversion, sedation is used just before the procedure. The synchronizer switch is turned "on" for cardioversion. The initial level of joules for cardioversion is low (e.g., 50). Assisted ventilations are not indicated for this patient.
27. Which action by a new registered nurse (RN) who is orienting to the telemetry unit indicates a good understanding of the treatment of heart dysrhythmias? a. Prepares defibrillator settings at 360 joules for a patient whose monitor shows asystole. b. Injects IV adenosine (Adenocard) over 2 seconds for a patient with supraventricular tachycardia. c. Turns the synchronizer switch to the "on" position before defibrillating a patient with ventricular fibrillation. d. Gives the prescribed dose of diltiazem (Cardizem) to a patient with new-onset type II second-degree AV block.
Answer: b. Injects IV adenosine (Adenocard) over 2 seconds for a patient with supraventricular tachycardia. Rationale: Adenosine must be given over 1 to 2 seconds to be effective. The other actions indicate a need for more teaching about treatment of heart dysrhythmias. The RN should hold the diltiazem until discussing it with the health care provider. The treatment for asystole is immediate CPR. The synchronizer switch should be "off" when defibrillating.
25. Which action will the nurse include in the plan of care for a patient who was admitted with syncopal episodes of unknown origin? a. Explain the association between dysrhythmias and syncope. b. Instruct the patient to call for assistance before getting out of bed. c. Teach the patient about the need to avoid caffeine and other stimulants. d. Tell the patient about the benefits of implantable cardioverter-defibrillators.
Answer: b. Instruct the patient to call for assistance before getting out of bed. Rationale: A patient with fainting episodes is at risk for falls. The nurse will plan to minimize the risk by having assistance whenever the patient is up. The other actions may be needed if dysrhythmias are found to be the cause of the patient's syncope but are not appropriate for syncope of unknown origin.
26. Which nursing action can the registered nurse (RN) delegate to experienced unlicensed assistive personnel (UAP) working as telemetry technicians on the cardiac care unit? a. Decide whether a patient's heart rate of 116 requires urgent treatment. b. Observe heart rhythms for multiple patients who have telemetry monitoring. c. Monitor a patient's level of consciousness during synchronized cardioversion. d. Select the best lead for monitoring a patient admitted with acute coronary syndrome.
Answer: b. Observe heart rhythms for multiple patients who have telemetry monitoring. Rationale: UAP serving as telemetry technicians can monitor heart rhythms for individuals or groups of patients. Nursing actions such as assessment and choice of the most appropriate lead based on ST segment elevation location require RN-level education and scope of practice.
18. A patient's heart monitor shows a pattern of undulations of varying contours and amplitude with no measurable ECG pattern. The patient is unconscious, apneic, and pulseless. Which action should the nurse take first? a. Give epinephrine (Adrenalin) IV. b. Perform immediate defibrillation. c. Prepare for endotracheal intubation. d. Ventilate with a bag-valve-mask device.
Answer: b. Perform immediate defibrillation. Rationale: The patient's rhythm and assessment indicate ventricular fibrillation and cardiac arrest; the initial action should be to defibrillate. If a defibrillator is not immediately available or is unsuccessful in converting the patient to a better rhythm, begin chest compressions. The other actions may also be appropriate but not first.
24. A patient is apneic and has no palpable pulses. The heart monitor shows sinus tachycardia, rate 132. What action should the nurse take next? a. Perform synchronized cardioversion. b. Start cardiopulmonary resuscitation (CPR). c. Give atropine per agency dysrhythmia protocol. d. Apply supplemental O2 via non-rebreather mask
Answer: b. Start cardiopulmonary resuscitation (CPR). Rationale: The patient's manifestations indicate pulseless electrical activity, and the nurse should immediately start CPR. The other actions would not be of benefit to this patient.
3. A patient has a junctional escape rhythm on the monitor. What heart rate should the nurse expect the patient to have? a. 15 to 20. b. 20 to 40. c. 40 to 60. d. 60 to 100.
Answer: c. 40 to 60 Rationale: If the sinoatrial (SA) node does not discharge, the atrioventricular (AV) node will automatically discharge at the normal rate of 40 to 60 beats/min. The slower rates are typical of the bundle of His and Purkinje system and may be seen with failure of both the SA and AV node to discharge. The normal SA node rate is 60 to 100 beats/min.
21. A 19-year-old student comes to the student health center at the end of the semester stating, "My heart is skipping beats." An electrocardiogram (ECG) shows occasional unifocal premature ventricular contractions (PVCs). What action should the nurse take next? a. Insert an IV catheter for emergency use. b. Start supplemental O2 at 2 to 3 L/min via nasal cannula. c. Ask the patient about current stress level and caffeine use. d. Have the patient taken to the nearest emergency department (ED).
Answer: c. Ask the patient about current stress level and caffeine use. Rationale: In a patient with a normal heart, occasional PVCs are a benign finding. The timing of the PVCs suggests stress or caffeine as possible etiologic factors. The patient is hemodynamically stable, so there is no indication that the patient needs supplemental O2, an IV, or to be seen in the ED.
23. A patient on the telemetry unit develops atrial flutter, rate 150, with associated dyspnea and chest pain. Which action that is included in the agency dysrhythmia protocol should the nurse do first? a. Obtain a 12-lead electrocardiogram (ECG). b. Notify the health care provider of the change in rhythm. c. Give supplemental O2 at 2 to 3 L/min via nasal cannula. d. Assess the patient's blood pressure and discomfort level.
Answer: c. Give supplemental O2 at 2 to 3 L/min via nasal cannula. Rationale: Because this patient has dyspnea and chest pain in association with the new rhythm, the nurse's initial actions should be to address the patient's airway, breathing, and circulation (ABC) by starting with O2 administration. The other actions are also important and should be implemented rapidly.
19. A patient's heart monitor shows sinus rhythm, rate 64. The PR interval is 0.18 seconds at 1:00 AM, 0.22 seconds at 2:30 PM, and 0.28 seconds at 4:00 PM. Which action should the nurse take first? a. Place the transcutaneous pacemaker pads on the patient. b. Give atropine sulfate 1 mg IV per agency dysrhythmia protocol. c. Hold the scheduled metoprolol (Lopressor) and call the health care provider. d. Document the patient's rhythm and PR measurements in the medical record.
Answer: c. Hold the scheduled metoprolol (Lopressor) and call the health care provider. Rationale: The patient has progressive first-degree atrioventricular (AV) block, and the -blocker should be held until discussing the drug with the health care provider. Documentation is appropriate later. The patient with first-degree AV block usually is asymptomatic; if the patient became symptomatic, a pacemaker or atropine may be used.
29. A patient who reports a "racing" heart and feeling "anxious" comes to the emergency department. The nurse places the patient on a heart monitor and obtains the following electrocardiographic (ECG) tracing. Which action should the nurse take next? a. Prepare to perform electrical cardioversion. b. Have the patient perform the Valsalva maneuver. c. Obtain the patient's vital signs including O2 saturation. d. Prepare to give a Beta-blocker medication to slow the heart rate.
Answer: c. Obtain the patient's vital signs including O2 saturation. Rationale: The patient has sinus tachycardia, which may have multiple causes, such as pain, dehydration, anxiety, and myocardial ischemia. Further assessment is needed before determining the treatment. Vagal stimulation or Beta-blockade may be used after further assessment of the patient. Electrical cardioversion is a treatment for some tachydysrhythmias but not sinus tachycardia.
10. Which information will the nurse include when teaching a patient with atrial flutter who is scheduled for a radiofrequency catheter ablation? a. The procedure stimulates the growth of new pathways between the atria. b. The procedure uses cold therapy to stop the formation of the flutter waves. c. The procedure uses electrical energy to destroy areas of the conduction system. d. The procedure prevents or minimizes the patient's risk for sudden cardiac death.
Answer: c. The procedure uses electrical energy to destroy areas of the conduction system. Rationale: Radiofrequency catheter ablation therapy uses electrical energy to "burn" or ablate areas of the conduction system as definitive treatment of atrial flutter (i.e., restore normal sinus rhythm) and tachydysrhythmias. All other statements about the procedure are incorrect.
28. A patient reports dizziness and shortness of breath for several days. During heart monitoring in the emergency department (ED), the nurse obtains the following electrocardiographic (ECG) tracing. How does the nurse interpret this heart rhythm? a. Junctional escape rhythm. b. Accelerated idioventricular rhythm. c. Third-degree atrioventricular (AV) block. d. Sinus rhythm with premature atrial contractions.
Answer: c. Third-degree atrioventricular (AV) block. Rationale: The inconsistency between the atrial and ventricular rates and the variable PR interval indicate that the rhythm is third-degree AV block. Sinus rhythm with PACs will have a normal rate and consistent PR intervals with occasional PACs. An accelerated idioventricular rhythm will not have visible P waves.
