Chapter 35 : dysrhythmias Flashcards
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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).
