CH. 35 Dsyrhythmias
The patient has a potassium level of 2.9 mEq/L, and the nurse obtains the following measurements on the rhythm strip: Heart rate of 86 with a regular rhythm, the P wave is 0.06 seconds (sec) and normal shape, the PR interval is 0.24 seconds, and the QRS is 0.09 seconds. How should the nurse document this rhythm? A. First-degree AV block B. Second-degree AV block C. Premature atrial contraction (PAC) D. Premature ventricular contraction (PVC)
A. First-degree AV block Rationale: In first-degree atrioventricular (AV) block, there is prolonged duration of AV conduction that lengthens the PR interval above 0.20 seconds. In type I second-degree AV block, the PR interval continues to increase in duration until a QRS complex is blocked. In type II, the PR interval may be normal or prolonged, the ventricular rhythm may be irregular, and the QRS is usually greater than 0.12 seconds. PACs cause an irregular rhythm with a different-shaped P wave than the rest of the beats, and the PR interval may be shorter or longer. PVCs cause an irregular rhythm, and the QRS complex is wide and distorted in shape.
A patient informs the nurse of experiencing syncope. Which prioitiy nursing action should the nurse anticipate in the patient's subsequent diagnostic workup? A. Preparing to assist with a head-up tilt-test B. Assessing the patient's knowledge of pacemakers C. Administering an IV dose of a β-adrenergic blocker D. Teaching the patient about antiplatelet aggregators
A. Preparing to assist with a head-up tilt-test Rationale: In patients without structural heart disease, the head-up tilt-test is a common component of the diagnostic workup after episodes of syncope. IV β-blockers are not indicated, although an IV infusion of low-dose isoproterenol may be started in an attempt to provoke a response if the head-up tilt-test did not have a response. Addressing pacemakers is premature and inappropriate at this stage of diagnosis. Patient teaching surrounding antiplatelet aggregators is not directly relevant to the patient's syncope at this time.
The nurse has obtained this rhythm strip from her patient's monitor. What should the nurse document this rhythm indicates? A. Sinus tachycardia B. Sinus bradycardia C. Ventricular fibrillation D. Ventricular tachycardia
A. Sinus tachycardia Rationale: This rhythm strip shows sinus tachycardia because the rate on this strip is above 101 beats/min, and it displays normal P wave, PR interval, and QRS complex. Sinus bradycardia would look similar to sinus tachycardia but with a rate less than 60 beats/min. Ventricular fibrillation does not have a measureable heart rate, PR interval, or QRS. The P wave is not visible, and the rhythm is irregular and chaotic. Ventricular tachycardia has a rate of 150 to 250 beats/min, with a regular or irregular rhythm and P waves occurring independently of the QRS complex.
The nurse prepares to defibrillate a patient. Which dysrhythmia has the nurse observed in this patient? A. Ventricular fibrillation B. Third-degree AV block C. Uncontrolled atrial fibrillation D. Ventricular tachycardia with a pulse
A. Ventricular fibrillation Rationale: Defibrillation is always indicated in the treatment of ventricular fibrillation. Drug treatments are normally used in the treatment of uncontrolled atrial fibrillation and for ventricular tachycardia with a pulse (if the patient is stable). Otherwise, synchronized cardioversion is used (if the patient has a pulse). Pacemakers are the treatment of choice for third-degree heart block.
The nurse is doing discharge teaching with the patient who received an implantable cardioverter-defibrillator (ICD) in the left side. Which statement by the patient indicates that further teaching is required? A. "I will call the cardiologist if my ICD fires." B. "I cannot fly because it will damage the ICD." C. "I cannot move my left arm until it is approved." D. "I cannot drive until my cardiologist says it is okay."
B. "I cannot fly because it will damage the ICD." Rationale: The patient statement that flying will damage the ICD indicates misunderstanding about flying. The patient should be taught to inform TSA security screening agents at the airport about the ICD because it may set off the metal detector and if a hand-held screening wand is used, it should not be placed directly over the ICD. The other options indicate the patient understands the teaching.
A patient reporting dizziness and shortness of breath is admitted with a dysrhythmia. Which medication, if ordered, requires the nurse to carefully monitor the patient for asystole? A. Digoxin B. Adenosine C. Metoprolol D. Atropine sulfate
B. Adenosine Rationale: IV adenosine is the first drug of choice to convert supraventricular tachycardia to a normal sinus rhythm. Adenosine is administered IV rapidly (over 1 or 2 seconds) followed by a rapid, normal saline flush. The nurse should monitor the patient's electrocardiogram continuously because a brief period of asystole after adenosine administration is common and expected. Atropine sulfate increases heart rate, while lanoxin and metoprolol slow the heart rate.
The nurse observes no P waves on the patients monitor strip. There are fine, wavy lines between the QRS complexes. The QRS complexes measure 0.08 seconds (narrow), but they occur irregularly with a rate of 120 beats/min. What does the nurse determine the rhythm to be? A. Sinus tachycardia B. Atrial fibrillation C. Ventricular fibrillation D. Ventricular tachycardia
B. Atrial fibrillation Rationale: Atrial fibrillation is represented on the cardiac monitor by irregular R-R intervals and small fibrillatory (f) waves. There are no normal P waves because the atria are not truly contracting, just fibrillating. Sinus tachycardia is a sinus rate above 100 beats/min with normal P waves. Ventricular fibrillation is seen on the ECG without a visible P wave; an unmeasurable heart rate, PR or QRS; and the rhythm is irregular and chaotic. Ventricular tachycardia is seen as three or more premature ventricular contractions that have distorted QRS complexes with regular or irregular rhythm, and the P wave is usually buried in the QRS complex without a measurable PR interval.
The patient is admitted with acute coronary syndrome (ACS). The ECG shows ST-segment depression and T-wave inversion. What should the nurse know that this indicates? A. Myocardia injury B. Myocardial ischemia C. Myocardial infarction D. Normal pacemaker function.
B. Myocardial ischemia Rationale: The ST depression and T wave inversion on the ECG of a patient diagnosed with ACS indicate myocardial ischemia from inadequate supply of blood and oxygen to the heart. Myocardial injury is identified with ST-segment elevation. Myocardial infarction is identified with ST-segment elevation and a widened and deep Q wave. A pacemaker's presence is evident on the ECG by a spike leading to depolarization and contraction.
The patient has atrial fibrillation with a rapid ventricular response. What electrical treatment option does the nurse prepare the patient for? A. Defibrillation B. Synchronized cardioversion C. Automatic external defibrillator (AED) D. Implantable cardioverter-defibrillator (ICD)
B. Synchronized cardioversion Rationale: Synchronized cardioversion is planned for a patient with supraventricular tachydysrhythmias (atrial fibrillation with a rapid ventricular response). Defibrillation or AEDs are the treatment of choice to end ventricular fibrillation and pulseless ventricular tachycardia (VT). An ICD is used with patients who have survived sudden cardiac death, have spontaneous sustained VT, and are at high risk for future life-threatening dysrhythmias.
What is the correct interpretation of this rhythm strip? A. Sinus dysrhythmia B. Third-degree heart block C. Wenckebach phenomenon D. Premature ventricular contractions
B. Third-degree heart block Rationale: Third-degree heart block represents a loss of communication between the atrium and ventricles from atrioventricular node dissociation. This is depicted on the rhythm strip as no relationship between the P waves (representing atrial contraction) and QRS complexes (representing ventricular contraction). Whereas the atria are beating totally on their own at 70 beats/min, the ventricles are pacing themselves at 40 beats/min. Sinus dysrhythmia is seen with a slower heart rate with exhalation and an increased heart rate with inhalation. In Wenckebach heart block, there is a gradual lengthening of the PR interval until an atrial impulse is nonconducted and a QRS complex is blocked or missing. Premature ventricular contractions are the early occurrence of a wide, distorted QRS complex.
When computing a heart rate from the electrocardiography (ECG) tracing, the nurse counts 15 of the small blocks between the R waves of a patient whose rhythm is regular. What does the nurse calculate the patient's heart rate to be? A. 60 beats/min B. 75 beats/min C. 100 beats/min D. 150 beats/min
C. 100 beats/min Rationale: Because each small block on the ECG paper represents 0.04 seconds, 1500 of these blocks represents 1 minute. By dividing the number of small blocks (15, in this case) into 1500, the nurse can calculate the heart rate in a patient whose rhythm is regular (in this case, 100).
The nurse is monitoring the electrocardiograms of several patients on a cardiac telemetry unit. The patients are directly visible to the nurse, and all the patients are observed to be sitting up and talking with visitors. Which patient's rhythm would require the nurse to take immediate action? A. A 62-yr-old man with a fever and sinus tachycardia with a rate of 110 beats/min. B. A 72-yr-old woman with atrial fibrillation with 60 to 80 QRS complexes per minute. C. A 52-yr-old man with premature ventricular contractions (PVCs) at a rate of 12 per minute. D. A 42-yr-old woman with first-degree AV block and sinus bradycardia at a rate of 56 beats/min
C. A 52-yr-old man with premature ventricular contractions (PVCs) at a rate of 12 per minute. Rationale: Frequent premature ventricular contractions (PVCs) (>1 every 10 beats) may reduce the cardiac output and precipitate angina and heart failure, depending on their frequency. Because PVCs in CAD or acute myocardial infarction indicate ventricular irritability, the patient's physiologic response to PVCs must be monitored. Frequent PVCs may be treated with oxygen therapy, electrolyte replacement, or antidysrhythmic agents.
The nurse is caring for a patient who is 24 hours after pacemaker insertion. Which nursing intervention is appropriate at this time? A. Reinforcing the pressure dressing as needed B. Encouraging range-of-motion exercises of the involved arm C. Assessing the incision for any redness, swelling, or discharge D. Applying wet-to-dry dressings every 4 hours to the insertion site
C. Assessing the incision for any redness, swelling, or discharge Rationale: After pacemaker insertion, it is important for the nurse to observe signs of infection by assessing for any redness, swelling, or discharge from the incision site. The nonpressure dressing is kept dry until removed, usually 24 hours postoperatively. It is important for the patient to limit activity of the involved arm to minimize pacemaker lead displacement.
The nurse observes a flat line on the patient's monitor and the patient is unresponsive without pulse. What medications does the nurse prepare to administer? A. Lidocaine or amiodarone B. Digoxin and procainamide C. Epinephrine or vasopressin D. β-Adrenergic blockers and dopamine
C. Epinephrine or vasopressin Rationale: Normally, the patient in asystole cannot be successfully resuscitated. However, administration of epinephrine or vasopressin may prompt the return of depolarization and ventricular contraction. Lidocaine and amiodarone are used for ventricular tachycardia or ventricular fibrillation. Digoxin and procainamide are used for ventricular rate control. β-Adrenergic blockers are used to slow heart rate, and dopamine is used to increase heart rate.
The nurse observes ventricular tachycardia (VT) on the patient's monitor. What evaluation made by the nurse led to this interpretation? A. Unmeasurable rate and rhythm B. Rate 150 beats/min; inverted P wave C. Rate 200 beats/min; P wave not visible D. Rate 125 beats/min; normal QRS complex
C. Rate 200 beats/min; P wave not visible Rationale: VT is associated with a rate of 150 to 250 beats/min; the P wave is not normally visible. Rate and rhythm are not measurable in ventricular fibrillation. P wave inversion and a normal QRS complex are not associated with VT.
Which statement best describes the electrical activity of the heart represented by measuring the PR interval on the electrocardiogram (ECG)? A. The length of time it takes to depolarize the atrium. B. The length of time it takes for the atria to depolarize and repolarize. C. The length of time for the electrical impulse to travel from the sinoatrial (SA) node to the Purkinje fibers. D. The length of time it takes for the electrical impulse to travel from the sinoatrial (SA) node to the atrioventricular (AV) node.
C. The length of time for the electrical impulse to travel from the sinoatrial (SA) node to the Purkinje fibers. Rationale: The electrical impulse in the heart must travel from the SA node through the AV node and into the Purkinje fibers in order for synchronous atrial and ventricular contraction to occur. When measuring the PR interval (the time from the beginning of the P wave to the beginning of the QRS), the nurse is identifying the length of time it takes for the electrical impulse to travel from the SA node to the Purkinje fibers. The P wave represents the length of time it takes for the impulse to travel from the SA node through the atrium, causing depolarization of the atria (atrial contraction). Atrial repolarization occurs during ventricular depolarization and is hidden by the QRS complex. The length of time it takes for the electrical impulse to travel from the SA node to the AV node is the flat line between the end of the P wave and the beginning of the Q wave on the ECG and is not usually measured.
The nurse determines there is artifact on the patient's telemetry monitor. Which factor should the nurse assess for that could correct this issue? A. Disabled automaticity B. Electrodes in the wrong lead C. Too much hair under the electrodes D. Stimulation of the vagus nerve fibers
C. Too much hair under the electrodes Rationale: Artifact is caused by muscle activity, electrical interference, or insecure leads and electrodes that could be caused by excessive chest wall hair. Disabled automaticity would cause an atrial dysrhythmia. Electrodes in the wrong lead will measure electricity in a different plane of the heart and may have a different wave form than expected. Stimulation of the vagus nerve fibers causes a decrease in heart rate, not artifact.
Cardioversion is attempted for a patient with atrial flutter and a rapid ventricular response. After delivering 50 joules by synchronized cardioversion, the patient develops ventricular fibrillation. Which action should the nurse take immediately? A. Administer 250 mL of 0.9% saline solution IV by rapid bolus. B. Assess the apical pulse, blood pressure, and bilateral neck vein distention. C. Turn the synchronizer switch to the "off" position and recharge the device. D. Ask the patient if there is any chest pain or discomfort and administer morphine sulfate.
C. Turn the synchronizer switch to the "off" position and recharge the device. Rationale: Ventricular fibrillation produces no effective cardiac contractions or cardiac output. If during synchronized cardioversion the patient becomes pulseless or the rhythm deteriorates to ventricular fibrillation, the nurse should turn the synchronizer switch off and initiate defibrillation. Fluids, additional assessment, or treatment of pain alone will not restore an effective heart rhythm.
The nurse performs discharge teaching for a patient with an implantable cardioverter-defibrillator (ICD). Which statement by the patient indicates that further teaching is needed? A. "The device may set off the metal detectors in an airport." B. "My family needs to keep up to date on how to perform CPR." C. "I should not stand next to antitheft devices at the exit of stores." D. "I can expect redness and swelling of the incision site for a few days."
D. "I can expect redness and swelling of the incision site for a few days." Rationale: Patients should be taught to report any signs of infection at incision site (e.g., redness, swelling, drainage) or fever to their primary care providers immediately. Teach patients to inform TSA airport security of the presence of the ICD because it may set off metal detectors. If a handheld screening wand is used, it should not be placed directly over the ICD. Teach patients to avoid standing near antitheft devices in doorways of stores and public buildings and to walk through them at a normal pace. Caregivers should learn cardiopulmonary resuscitation.
A patient develops third-degree heart block and reports feeling chest pressure and shortness of breath. Which instructions should the nurse provide to the patient before initiating emergency transcutaneous pacing? A. "The device will convert your heart rate and rhythm back to normal." B. "The device uses overdrive pacing to slow the heart to a normal rate." C. "The device is inserted through a large vein and threaded into your heart." D. "The device delivers a current through your skin that can be uncomfortable."
D. "The device delivers a current through your skin that can be uncomfortable." Rationale: Before initiating transcutaneous pacing therapy, it is important to tell the patient what to expect. The nurse should explain that the muscle contractions created by the pacemaker when the current passes through the chest wall are uncomfortable. Pacing for complete heart block will not convert the heart rhythm to normal. Overdrive pacing is used for very fast heart rates. Transcutaneous pacing is delivered through pacing pads adhered to the skin.
The nurse prepares a patient for synchronized cardioversion knowing that cardioversion differs from defibrillation in that: A. defibrillation delivers a lower dose of electrical energy. B. cardioversion is a treatment for atrial bradydyschythmias. C. defibrillation is synchronized to deliver a shock during the QRS complex. D. patients should be sedated if cardioversion is done on a nonemergency basis
D. patients should be sedated if cardioversion is done on a nonemergency basis Rationale: Synchronized cardioversion is the therapy of choice for patients with hemodynamically unstable ventricular or supraventricular tachydysrhythmias. A synchronized circuit in the defibrillator delivers a countershock that is programmed to occur on the R wave of the QRS complex of the electrocardiogram. The synchronizer switch must be turned on when cardioversion is planned. The procedure for synchronized cardioversion is the same as for defibrillation with a few exceptions: If synchronized cardioversion is done on a nonemergency basis, the patient is sedated before the procedure, and the initial energy needed for synchronized cardioversion is less than the energy needed for defibrillation.
In the patient with supraventricular tachycardia SVT, which assessment indicates decreased cardiac output? A. Hypertension and dyspnea B. Chest pain and palpitations C. Abdominal distention and tachypnea D. Bounding pulses and a systolic murmur
B. Chest pain and palpitations Rationale: Manifestations of decreased cardiac output in the patient with supraventricular tachycardia include hypotension, angina, palpitations, and dyspnea.
A patient admitted with syncope has continuous ECG monitoring. An examination of the rhythm strip reveals the following: atrial rate 74 beats/ min and regular; ventricular rate 62 beats/ min and irregular; P wave normal shape; PR interval lengthens progressively until a P wave is not conducted; QRS normal shape. The priority nursing intervention would be to: A. give epinephrine 1 mg IV push. B. prepare for synchronized cardioversion. C. observe for symptoms of hypotension or angina. D. apply transcutaneous pacemaker pads on the patient.
C. observe for symptoms of hypotension or angina. Rationale: The rhythm is a second-degree atrioventricular (AV) block, type I (i.e., Mobitz I or Wenckebach heart block). It is characterized by a gradual lengthening of the PR interval. Type I AV block is usually a result of myocardial ischemia or infarction. It is typically transient and well tolerated. The nurse should assess for bradycardia, hypotension, and angina. The symptomatic patient may need atropine or a temporary pacemaker
The ECG monitor of a patient in the cardiac care unit after an MI shows ventricular bigeminy with a rate of 50 beats/ min. The nurse would: A. perform defibrillation. B. administer IV amiodarone. C. prepare for temporary pacemaker insertion. D. assess the patient's response to the dysrhythmia.
D. assess the patient's response to the dysrhythmia. Rationale: A premature ventricular contraction (PVC) is a contraction originating in an ectopic focus in the ventricles. When every other beat is a PVC, the rhythm is called ventricular bigeminy. PVCs are usually a benign finding in patients with a normal heart. In patients with heart disease, PVCs may reduce the cardiac output and precipitate angina and heart failure, depending on the frequency. Because PVCs in coronary artery disease (CAD) or acute myocardial infarction indicate ventricular irritability, the patient's physiologic response to PVCs must be monitored. Assessing the patient's hemodynamic status is important for deciding the need for drug therapy.
Which patient teaching points should the nurse include when providing discharge instructions to a patient with a new permanent pacemaker and the caregiver? (select all that apply) A. Avoid or limit air travel. B. Take and record a daily pulse rate. C. Obtain and wear a Medic Alert ID device at all times. D. Avoid lifting arm on the side of the pacemaker above shoulder. E. Do not use a microwave oven because it interferes with pacemaker function.
B. Take and record a daily pulse rate. C. Obtain and wear a Medic Alert ID device at all times. D. Avoid lifting arm on the side of the pacemaker above shoulder. Rationale: Pacemaker discharge teaching should include: Air travel is not restricted. The patient should tell airport security of the presence of a pacemaker because it may set off the metal detector. A hand-held screening wand should not pass directly over the pacemaker. Manufacturer information varies about the effect of metal detectors on pacemaker function. The patient should monitor the pulse and tell the HCP if it drops below a predetermined rate. The patient should have and wear a Medic Alert ID device at all times. The patient must avoid lifting the arm on the pacemaker side above the shoulder until approved by the HCP. Microwave ovens are safe to use. They do not interfere with pacemaker function.
Important teaching for the patient scheduled for a radiofrequency catheter ablation procedure includes explaining that: A. ventricular bradycardia may be induced and treated during the procedure. B. catheter will be placed in both femoral arteries to allow double-catheter use. C. the procedure will destroy areas of the conduction system that are causing rapid heart rhythms. D. general anesthetic will be given to prevent the awareness of any "sudden cardiac death" experiences.
C. the procedure will destroy areas of the conduction system that are causing rapid heart rhythms. Rationale: Radiofrequency catheter ablation therapy involves the use of electrical energy to "burn" or ablate areas of the conduction system as definitive treatment of tachydysrhythmias.
