Lewis Dysrhythmias (Ch. 36)with complete solutions 2023

Lewis Dysrhythmias (Ch. 36)with complete solutions 2023When 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 bpm b) 75 bpm c) 100 bpm d) 150 bpm c) 100 bpm (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).) 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 depolarize 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 obtains a 6-second rhythm strip and charts the following analysis: Tab 1 Tab 2 Tab 3 Atrial data Rate: 70, regular Variable PR interval Independent beats Ventricular data Rate: 40, regular Isolated escape beats Additional data QRS: 0.04 sec P wave and QRS complexes unrelated What is the correct interpretation of this rhythm strip? a) Sinus arrhythmias b) Third-degree heart block c) Wenckebach phenomenon d) Premature ventricular contractions b) Third-degree heart block (Third-degree heart block represents a loss of communication between the atrium and ventricles from AV 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). The atria are beating totally on their own at 70 beats/min, whereas 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 (PVCs) are the early occurrence of a wide, distorted QRS complex.) 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 arms 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.) 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.) 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 Beta-adrenergic blocker c) Assessing the patient's knowledge of pacemakers d) Teaching the patient about the role of antiplatlet 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 anti platelet 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 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.) A patient in systole is likely to receive which drug treatment? a) Epinephrine and atropine b) Lidocaine and amiodarone c) Digoxin and procainamide d) Beta 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.) Which ECG characteristic is consistent with a diagnosis of ventricular tachycardia (VT)? a) Unmeasurable rate and rhythm b) Rae 150 bpm; inverted P wave c) Rate 200 bpm; P wave not visible d) Rate 125 bpm; normal QRS complex c) Rate 200 bpm; 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.) 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 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 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) Myocardial 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 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.) 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 (In first-degree AV block there is prolonged duration of AV conduction that lengthens the PR interval above 0.20 sec. 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 sec. 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.) The nurse has obtained this rhythm strip from her patient's monitor. Which description of this ECG is correct? (Picture on flip side) a) Sinus tachycardia b) Sinus bradycardia c) Ventricular fibrillation d) Ventricular tachycardia a) Sinus tachycardia (This rhythm strip shows sinus tachycardia because the rate on this strip is above 101, 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 per minute. Ventricular fibrillation does not have a measureable heart rate, PR interval, or QRS, and the P wave is not visible and the rhythm is irregular and chaotic. Ventricular tachycardia has a rate of 150 to 250 beats/minutes, with a regular or irregular rhythm and P waves occurring independently of the QRS complex.) 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 systole? a) Atropine sulfate b) Digoxin (Lanolin) 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 lanolin and metoprolol slow the heart rate.) 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 bpm 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 bpm 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.)