PrepU Chapter 28
A client is scheduled to have a Holter monitor for 48 hours to detect disturbances in conduction. Which action is important for the nurse to tell the client to ensure accuracy in correlating dysrhythmias with symptoms? a. It is important to keep a diary of activities and symptoms. b. If the monitor detects a lethal dysrhythmia, it will defibrillate to correct the dysrhythmia. c. The client may feel a pins and needles sensation while the monitor is connected. d. The client must limit activity while the Holter monitor is in place.
a Holter monitoring is one form of long-term monitoring during which a person wears a device that digitally records two or three electrocardiographic (ECG) leads for up to 48 hours. During this time, the person keeps a diary of his or her activities or symptoms, which are later correlated with the ECG recording. The client should have no sensation of pins and needles, and although the monitor will detect dysrhythmias, it will not defibrillate the client.
Which type of pacing involves the placement of large patch electrodes on the anterior and posterior chest wall that can be connected by a cable to an external pulse generator? a. Transcutaneous b. Permanent c. Epicardial d. Transvenous
a The type of pacing described is transcutaneous because it is the only form that is accessible externally.
The nurse is caring for a client who suffered a massive myocardial infarction and is scheduled for an immediate permanent pacemaker insertion due to severe ischemia and damage to both SA and AV nodes. The nurse would expect which of the following? a. Bradycardia with rate of 20-40 b. Heart rate between 40-60 c. Tachycardia with rate between 100-120 d. Severely elevated diastolic pressure
a Lack of oxygen supply and damage to both the SA and AV nodes will interrupt the ability of either to pace the heart. The basic physiology of the cardiac conduction system is "the cell(s) that paces the fastest will pace the heart" and with dysfunction of both SA and AV nodes, the Purkinje system will take over with a rate between 15 and 40 times per minute.
Which client will the nurse prioritize to assess first? a. client with sinus arrest b. client with sinus bradycardia c. client with respiratory sinus arrhythmia d. client with tachycardia
a The client with sinus arrest or "sinus pause" is exhibiting a failure of the sinoatrial node to discharge and this may result in an irregular pulse. Most often, an escape rhythm develops as other pacemakers take over, but sinus arrest may result in prolonged periods of asystole and other abnormal rhythms. The client may need further interventions such as a pacemaker. A respiratory sinus arrhythmia is considered a benign variation seen with respiration in healthy people. Bradycardia and tachycardia can be serious if affecting cardiac output or if tachycardia is resulting in chest pain, but this level of detail was not provided, making the sinus arrest the best choice.
Paroxysmal supraventricular tachycardia arises from which form of reentry? a. Atrioventricular (AV) nodal b. Bundle of His nodal c. Orthodromic d. True
a Paroxysmal supraventricular tachycardia refers to tachydysrhythmias that originate above the bifurcation of the bundle of His and have a sudden onset and termination. It may be the result of AV nodal reentry. The other options are not responsible for paroxysmal supraventricular tachycardia.
A client experiencing a sinus arrest would demonstrate which symptom or finding? a. Prolonged periods of asystole demonstrated on an electrocardiogram b. Heart rate of greater than 100 beats/min c. Spontaneous persistent sinus bradycardia d. P-wave that occurs more frequently than expected
a Sinus arrest refers to failure of the sinoatrial node to discharge and results in an irregular pulse, prolonged periods of asystole, and predisposition to other dysrhythmias. The other options do not demonstrate the symptoms demonstrated during a sinus arrest.
The nurse is assisting a client who had a myocardial infarction 2 days ago during a bath. The client suddenly lost consciousness and the nurse was unable to feel a pulse. Cardiopulmonary resuscitation was begun and the client was connected to the monitor with a gross disorganization without identifiable waveforms or intervals observed. What is a priority intervention at this time? a. Immediate defibrillation b. Applying a transcutaneous pacemaker c. Synchronized cardioversion d. Administration of atropine
a The classic electrocardiographic pattern of ventricular fibrillation is that of gross distortion without identifiable waveforms or intervals. When the ventricles do not contract, there is no cardiac output, and there are no palpable or audible pulses. Immediate defibrillation using a nonsynchronized, direct-current electrical shock is mandatory for ventricular fibrillation and for ventricular flutter that has caused loss of consciousness.
A 20-year-old college student, with no past medical history, arrives at the emergency room complaining of severe palpitations and dizziness that started this morning following a night of studying. The student is very upset that this is happening because the final exams are the following day. The cardiac monitor shows a heart rate of 110, regular rhythm with occasional premature ventricular complexes. The nurse explains to the student that this can happen in healthy hearts and is usually caused by stimulation of: a. Atrial ectopic foci b. Parasympathetic nervous system c. Vagal nerve d. Sympathetic nervous system
d Premature ventricular complexes can occur in healthy hearts in response to stimulation of the sympathetic nervous system. This client states nighttime studying (possibly with coffee intake) and stress over upcoming exams, both of which can stimulate the sympathetic nervous system.
What is the correct sequence for the generation of electrical impulses in the heart causing ventricular contraction? a. SA node - AV node - bundle of His - bundle branches - Purkinje fibers b. AV node - SA node - bundle of His - bundle branches - Purkinje fibers c. SA node - AV node - bundle branches - Purkinje fibers - bundle of His d. AV node - bundle of HIS - bundle branches - SA node - Purkinje fibers
a The atrial conduction begins with the sinoatrial (SA) node, serving as the pacemaker of the heart. Impulses originating in the SA node travel through the atria to the atrioventricular (AV) node. There are three internodal pathways between the SA node and the AV node, including the anterior (Bachmann), middle (Wenckebach), and posterior (Thorel) internodal tracts. These three tracts anastomose with each other proximally to the AV node. The AV junction connects the two conduction systems and provides for one-way conduction between the atria and the ventricles. The impulse travels through the nodal region into the natriuretic hormone region, which connects with the bundle of His (also called the AV bundle). The fibers of the AV node proceed to form the bundle of His, which extends through the fibrous tissue between the valves of the heart and into the ventricular system. The bundle of His penetrates into the ventricles and almost immediately divides into right and left bundle branches that straddle the interventricular septum. The bundle branches move through the subendocardial tissues toward the papillary muscles and then subdivide into the Purkinje fibers, which branch out and supply the outer walls of the ventricles. The Purkinje system, which initiates ventricular conduction, has large fibers that allow for rapid conduction. Once the impulse enters the Purkinje system, it spreads almost immediately to the whole ventricle.
Which cardiac drug classification decreases sympathetic outflow to the heart and is the is the cornerstone of therapy for catecholaminergic polymorphic ventricular tachycardia (CPVT)? a. Calcium channel blockers b. Beta-adrenergic blockers c. Potassium blockers d. Sodium channel blockers
b Antiarrhythmic drugs act by modifying disordered formation and conduction of impulses that induce cardiac muscle contraction. Beta-adrenergic blocking drugs decrease sympathetic outflow to the heart. Antiadrenergic treatment with beta-blockers is the cornerstone of therapy for CPVT. The remaining options act by blocking specific electrolytes, thus altering electrical impulses affecting the heart.
The nurse is interpreting an electrocardiogram of a 65-year-old woman. Which should the nurse recognize as representing ventricular depolarization? a. T wave b. QRS complex c. ST segment d. P wave
b The QRS complex is representative of ventricular depolarization. The P wave is atrial depolarization, the T wave is ventricular repolarization, and the ST segment is the time to ventricular repolarization.
Nursing students who are studying for their upcoming cardiac exam are discussing how the heart could possibly continue to beat once removed from the body. One of the students explains that this phenomenon is directly related to automaticity. What is automaticity? a. Inherent low-impulse conductivity b. Inherent spontaneous action-potential c. Inherent discharge rate of 40-60 d. Inherent discharge rate of 60-80
b The heart has four inherent properties essential in the development and conduction of cardiac rhythms. The property of automaticity is the ability of certain cells in the myocardium to automatically or spontaneously initiate an electrical impulse called an action potential. In a normally functioning heart the rate is controlled by the sinoatrial (SA) node.
Sick sinus syndrome is suspected in the case of a child who is postoperative following cardiac surgery. Which nursing action is most appropriate? a. Reassure the child's family that the condition is usually self-limiting. b. Facilitate an exercise stress test as ordered. c. Monitor the child's ECG for bradycardia. d. Review the results of the child's echocardiogram.
c The simple ECG would be enough to give a preliminary diagnosis of sick sinus syndrome, which typically reveals persistent sinus bradycardia. The stress test would be used to determine if the cause was neurologic or muscular in origin. The disease is not self-limiting and would not be revealed by echocardiogram.
An 80-year-old client with a medical history of atrial fibrillation, type II diabetes, and coronary heart disease is brought to the emergency room following a syncopal episode. The nurse notes on ECG the client lacks P waves and the QRS complexes are a rate of 48-54 beats/minute. The nurse determines the presence of which dysrhythmia? a. Sinus bradycardia with premature ventricular complexes b. Sinus escape rhythm with premature atrial contractions c. Sinus arrest with a junctional escape rhythm d. Sinus arrest with a ventricular escape rhythm
c This client is suffering from sinus arrest with a junctional escape rhythm, demonstrated by the lack of P waves and QRS complexes at a rate of 48-54, which is the escape rhythm. The inherent rate in the junction is 40-60 beats per minute; if the escape rhythm were ventricular the rate would be between 15-40 beats per minute. This client has at least one risk factor for the development of this rhythm—congestive heart failure.
A monitored hospitalized client with a pulmonary embolism has been in atrial fibrillation (AF) for 4 days. The nurse observes the rhythm spontaneously convert to a normal sinus rhythm. Which form of AF is this? a. Permanent b. Persistent c. Chronic d. Paroxysmal
d AF is characterized as rapid disorganized atrial activation and uncoordinated contraction by the atria. It is classified into three categories: paroxysmal, persistent, and permanent. Paroxysmal AF self-terminates and lasts no longer than 7 days, whereas persistent lasts greater than 7 days and usually requires intervention such as a cardioversion. AF is classified as permanent when attempts to terminate are failed and the person remains in AF. The symptoms of chronic AF vary. Some people have minimal symptoms, and others have severe symptoms, particularly at the onset of the dysrhythmias.
A client has been diagnosed with atrial flutter. Which assessment finding correlates with this diagnosis? a. A ventricular heart rate above 240 beats/min b. An increased blood pressure c. A slow atrial rate d. An atrial heart rate above 240 beats/min
d Atrial flutter is a rapid, atrial, ectopic tachycardia and has an atrial rate from 240 to 450 beats/min. The ventricular rate would not be expected to be as high as 240 beats/min but would be variable, and the blood pressure would not be expected to increase.
A nurse is caring for a client with an average heart rate of 56 beats/min. The client has no adverse symptoms associated with this heart rate and is receiving no treatment. Which activity modification should the nurse suggest to avoid further slowing of the heart rate? a. "Avoid strenuous aerobic exercise." b. "Limit your intake of caffeinated drinks." c. "Avoid stress or overexcitement." d. "Avoid bearing down while having a bowel movement."
d Bearing down during a bowel movement stimulates the vagus nerve and results in a slowing of the heart rate. Vagal stimulation as well as some medications decreases the firing rate of the sinoatrial node and conduction through the atrioventricular node to cause a decrease in heart rate.
The nurse assesses the electrocardiogram for depolarization of the atria. What portion of the ECG will the nurse be assessing? a. T wave above the baseline b. U wave above the baseline c. Q wave below the baseline d. P wave above the baseline
d Depolarization of the atria is represented on the electrocardiogram by a positively deflected P wave. The Q wave depicts ventricular depolarization. The T wave portrays ventricular repolarization. The U wave is a small (0.5 mm) deflection immediately following the T wave and is seen in clients with hypokalemia.
A client's electrocardiogram monitor begins to sound an alarm and shows sustained ventricular fibrillation. The client is unconscious and without a pulse. Which priority intervention should the nurse take? a. Notify the client's attending physician b. Administer IV push atropine c. Perform synchronized cardioversion d. Defibrillate the client
d Immediate defibrillation using a nonsynchronized, direct-current electrical shock is mandatory for ventricular fibrillation and for ventricular flutter that has caused loss of consciousness.
An 80-year-old male client arrives for his yearly physical without any complaints, and following the checkup the physician explains that he has noted atrial fibrillation (AF) on the client's ECG. Before the physician can explain the disorder, the client becomes very upset and states he thinks he is going to die. The physician explains that atrial fibrillation involves the top chambers of the heart and that: a. the client will experience severe palpitations. b. atrial fibrillation is a disorganized ventricular rhythm with recurrent circuits. c. the client will be placed on anticoagulants immediately. d. many people live with atrial fibrillation without even knowing they have it.
d Many people live with atrial dysrhythmias, including atrial fibrillation, without knowing the dysrhythmia exists. Atrial dysrhythmias are typically less serious because they do not impact the ability of the ventricles to pump. This client is at high risk to develop atrial fibrillation due to his advanced age; the rates of atrial fibrillation begin to increase over the age of 60 and males have a greater prevalence. It is true that atrial fibrillation is a disorganized rhythm; however it is not ventricular. The client may or may not need anticoagulation; there are other considerations to be made before these medications would be considered.
A 28-year-old marathon runner comes to the clinic to obtain a physical exam for a new job. The nurse assesses a regular pulse rate of 52 beats per minute (bpm). Which common dysrhythmia is the nurse aware this client most likely has related to maintaining a large stroke volume? a. Sinus tachycardia b. Atrial fibrillation c. Atrial flutter d. Sinus bradycardia
d Sinus bradycardia is a slow (<60 bpm) heart rate. In sinus bradycardia, a P wave precedes each QRS. A normal P wave and PR interval (0.12 to 0.20 sec) indicates that the impulse originates in the SA node rather than in another area of the conduction system that has a slower inherent rate. Vagal stimulation as well as some medications decrease the firing rate of the sinoatrial node and conduct through the atrioventricular node to cause a decrease in heart rate. This rhythm may be normal in trained athletes, who maintain a large stroke volume, and during sleep. In most cases, it is a benign rhythm unless the client has had a myocardial infarction or after resuscitation from cardiac arrest.
A nurse is monitoring a client with a resting heart rate of 120 beats/min who has been diagnosed with sinus tachycardia, which can result from a change in which characteristic of cardiac cells? a. Increased conductivity b. Increased slow response action potential c. Decreased refractoriness d. Increased automaticity
d Sinus tachycardia is caused by an increase in the automaticity of the SA node. Changes in excitability, conductivity, and refractoriness do not have effects that would lead to sinus tachycardia.
A client who will be undergoing a Holter monitor examination would be given which instruction? a. "Wear clothing that you can exercise in during the test." b. "Lay very still during the procedure for an accurate reading." c. "You will need to have an intravenous injection prior to the start of the test." d. "Keep a diary of your activities and symptoms throughout the examination."
d While the client is wearing a Holter monitor (usually 48 hours), he or she will be instructed to maintain a diary of activities and symptoms so that the recorded electrocardiographic reading can be correlated with the diary events. The other options are not instructions appropriate for a Holter monitor examination.