Lewis Chapter 36 Dysrhymthias
When computing a heart rate from the ECG tracing, the nurse counts 15 of the small blocks between the R waves of a patient whose rhythm is regular. From these data, the nurse calculates 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. Since 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 ECGs of several patients on a cardiac telemetry unit. The patients are directly visible to the nurse, and all of 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-year-old man with a fever and sinus tachycardia with a rate of 110 beats/minute B A 72-year-old woman with atrial fibrillation with 60 to 80 QRS complexes per minute C A 52-year-old man with premature ventricular contractions (PVCs) at a rate of 12 per minute D A 42-year-old woman with first-degree AV block and sinus bradycardia at a rate of 56 beats/minute
C A 52-year-old man with premature ventricular contractions (PVCs) at a rate of 12 per minute Frequent premature ventricular contractions (PVCs) (greater than 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 MI indicate ventricular irritability, the patient's physiologic response to PVCs must be monitored. Frequent PVCs most likely must be treated with oxygen therapy, electrolyte replacement, or antidysrhythmic agents.
The nurse is caring for a patient who is 24 hours postpacemaker insertion. Which nursing intervention is most 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 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.
Which ECG characteristic is consistent with a diagnosis of ventricular tachycardia (VT)? 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 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 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 SA node to the Purkinje fibers D The length of time it takes for the electrical impulse to travel from the SA node to the AV node
C The length of time for the electrical impulse to travel from the SA node to the Purkinje fibers 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 is seeing artifact on the telemetry monitor. Which factors could contribute to this artifact? 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 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 64-year-old man with atrial flutter and a rapid ventricular response. After the nurse delivers 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 Tell the patient to report any chest pain or discomfort and administer morphine sulfate.
C Turn the synchronizer switch to the "off" position and recharge the device. 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.
A patient in asystole is likely to receive which drug treatment? A Epinephrine and atropine B Lidocaine and amiodarone C Digoxin and procainamide D β-adrenergic blockers and dopamine
A Epinephrine and atropine Normally the patient in asystole cannot be successfully resuscitated. However, administration of epinephrine and atropine may prompt the return of depolarization and ventricular contraction. Lidocaine and amiodarone are used for PVCs. 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 patient has hypokalemia, 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 sec; the QRS is 0.09 sec. 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
A patient has sought care following a syncopal episode of unknown etiology. Which nursing action should the nurse prioritize in the patient's subsequent diagnostic workup? A Preparing to assist with a head-up tilt-test B Preparing an IV dose of a β-adrenergic blocker C Assessing the patient's knowledge of pacemakers D Teaching the patient about the role of antiplatelet aggregators
A Preparing to assist with a head-up tilt-test In patients without structural heart disease, the head-up tilt-test is a common component of the diagnostic workup following 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.
For which dysrhythmia is defibrillation primarily indicated? A Ventricular fibrillation B Third-degree AV block C Uncontrolled atrial fibrillation D Ventricular tachycardia with a pulse
A Ventricular fibrillation 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 (as long as 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 and spouse of the patient who just received an implantable cardioverter-defibrillator (ICD) in the left side. Which statement by the patient indicates to the nurse that the patient needs more teaching? 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." The patient statement that flying will damage the ICD indicates misunderstanding about flying. The patient should be taught that informing TSA about the ICD can be done 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.
The nurse is watching the cardiac monitor, and a patient's rhythm suddenly changes. There are no P waves. Instead there are fine, wavy lines between the QRS complexes. The QRS complexes measure 0.08 sec (narrow), but they occur irregularly with a rate of 120 beats/min. The nurse correctly interprets this rhythm as what? A Sinus tachycardia B Atrial fibrillation C Ventricular fibrillation D Ventricular tachycardia
B Atrial fibrillation 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/minute 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 (PVCs) 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 A pacemaker is present.
B Myocardial ischemia 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. The nurse knows to prepare for which treatment if an electrical treatment is planned for this patient? A Defibrillation B Synchronized cardioversion C Automatic external defibrillator (AED) D Implantable cardioverter-defibrillator (ICD)
B Synchronized cardioversion 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 (SCD), have spontaneous sustained VT, and are at high risk for future life-threatening dysrhythmias.
The nurse performs discharge teaching for a 74-year-old woman with an implantable cardioverter-defibrillator. Which statement by the patient indicates to the nurse 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." Patients should be taught to report any signs of infection at incision site (e.g., redness, swelling, drainage) or fever to their primary care provider immediately. Teach the patient to inform airport security of presence of ICD because it may set off the metal detector. If hand-held screening wand is used, it should not be placed directly over the ICD. Teach the patient 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 (CPR).
A 50-year-old man who develops third-degree heart block 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." Before initiating transcutaneous pacing (TCP) 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.
A 38-year-old teacher who reported dizziness and shortness of breath while supervising recess is admitted with a dysrhythmia. Which medication, if ordered, requires the nurse to carefully monitor the patient for asystole? A Atropine sulfate B Digoxin (Lanoxin) C Metoprolol (Lopressor) D Adenosine (Adenocard)
D Adenosine (Adenocard) IV adenosine (Adenocard) 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 ECG continuously because a brief period of asystole after adenosine administration is common and expected. Atropine sulfate increases heart rate, whereas lanoxin and metoprolol slow the heart rate.