CH 34

Which waveform indicates proper function of the sinoatrial (SA) node? The QRS complex is present. The PR interval is 0.24 second. A P wave precedes every QRS complex. The ST segment is elevated.

C. A P wave is generated by the SA node and represents atrial depolarization. When the electrical impulse is consistently generated from the SA node, the P waves have a consistent shape in a given lead. The QRS complex represents ventricular depolarization. The PR interval represents time required for atrial depolarization and for the impulse delay in the atrioventricular node and travel time to the Purkinje fibers. Elevation of the ST segment indicates myocardial injury.

The nurse is caring for a client with advanced heart failure who develops asystole. The nurse corrects the graduate nurse when the graduate offers to perform which intervention? Defibrillation Cardiopulmonary resuscitation (CPR) Administration of epinephrine Administration of oxygen

A. Defibrillation interrupts the heart rhythm and allows normal pacemaker cells to take over. In asystole, there is no rhythm to interrupt; therefore, this intervention is not used. If drug therapy fails to restore effective rhythm, CPR is initiated. Epinephrine is used to increase heart rate in asystole. Hypoxia may be a cause of cardiac arrest; the administration of oxygen would be appropriate.

Which client is appropriate for the cardiac care unit charge nurse to assign to the float RN from the medical-surgical unit? The 64-year-old client admitted for weakness who has a sinus bradycardia with a heart rate of 58 beats/min The 71-year-old client admitted for heart failure who is short of breath and has a heart rate of 120 to 130 beats/min The 88-year-old client admitted with an elevated troponin level who is hypotensive with a heart rate of 96 beats/min The 92-year-old client admitted with chest pain who has premature ventricular complexes and a heart rate of 102 beats/min

A. The 64-year-old has a stable, asymptomatic bradycardia, which usually requires monitoring but no treatment unless the client develops symptoms and/or the slow heart rate causes a decrease in cardiac output. This client can be managed by a nurse with less cardiac dysrhythmia training. The 71-year-old is unstable and requires immediate intervention for dyspnea and tachycardia. The 88-year-old is displaying symptoms of myocardial injury (elevated troponin) and unstable blood pressure and needs immediate attention and medications. The 92-year-old is experiencing a dysrhythmia that could deteriorate into ventricular tachycardia and requires immediate intervention by a telemetry nurse.

The professional nurse is supervising a nursing student performing a 12-lead electrocardiogram (ECG). Under which circumstance does the nurse correct the student? The client is semi-recumbent in bed. Chest leads are placed as for the previous ECG. The client is instructed to breathe deeply through the mouth. The client is instructed to lie still.

C. While obtaining a 12-lead ECG, remind the client to be as still as possible in a semi-reclined position, breathing normally. Any repetitive movement will cause artifact and could lead to inaccurate interpretation of the ECG. Normal breathing is required or artifacts will be observed, perhaps leading to inaccurate interpretation of the ECG. Placing the client in a semi-reclined position is correct and does not require the nurse to intervene. ECGs are valid when electrode placement is identical at each test. The client must lie still to avoid artifacts and inaccurate interpretation of the ECG.

The nurse is teaching a client with a new permanent pacemaker. Which statement by the client indicates a need for further discharge education? "I will be able to shower again soon." "I need to take my pulse every day." "I might trigger airport security metal detectors." "I no longer need my heart pills."

D. All prescribed medications are still needed after the pacemaker is implanted. Once the wound from the surgery heals, the client will be able to shower. The client's pulse will have to be taken and recorded for 1 full minute at the same time each day. The metal in the pacemaker will trigger the alarm in metal detector devices; a card can be shown to authorities to indicate that the client has a pacemaker.

In teaching clients at risk for bradydysrhythmias, what information does the nurse include? "Avoid potassium-containing foods." "Stop smoking and avoid caffeine." "Take nitroglycerin for a slow heartbeat." "Use a stool softener."

D. Clients at risk for bradydysrhythmias should avoid bearing down or straining during a bowel movement; the Valsalva maneuver can cause bradycardia. Taking a stool softener helps prevent this. Clients with renal failure and hyperkalemia are instructed to avoid potassium-containing foods; if risk for hypokalemia exists, such as with diuretic therapy, the client is instructed to eat foods high in potassium. Smoking and caffeine increase heart rate; although all people should stop smoking, clients at risk for tachycardia, premature beats, and ectopic rhythms are instructed to stop smoking and avoid caffeine. Nitroglycerin is used to reduce oxygen demand in cardiac ischemia, not for bradycardia.

A client admitted after using crack cocaine develops ventricular fibrillation. After determining unresponsiveness, which action does the nurse take next? Prepare for defibrillation. Establish IV access. Place an oral airway and ventilate. Start cardiopulmonary resuscitation (CPR).

A. Defibrillating is the priority before any other resuscitative measures, according to advanced cardiac life support protocols. After immediate defibrillation, establish IV access, place an oral airway, and ventilate. CPR will be started after unsuccessful defibrillation.

Which teaching is essential for a client who has had a permanent pacemaker inserted? Avoid talking on a cell phone. Avoid operating electrical appliances over the pacemaker. Avoid sexual activity. Do not take tub baths.

B. The client should avoid operating electrical appliances directly over the pacemaker site because this may cause the pacemaker to malfunction. It is not necessary to avoid a telephone or a cell phone; radio transmitter towers, arc welding, and strong electromagnetic fields may pose a hazard. No hazard exists with sexual activity. Bathing and showering are permitted.

The nurse administers amiodarone (Cordarone) to a client with ventricular tachycardia. Which monitoring by the nurse is necessary with this drug? (Select all that apply.) Respiratory rate QT interval Heart rate Heart rhythm Urine output

B.C.D. Amiodarone causes prolongation of the QT interval, which can precipitate dysrhythmia. Antidysrhythmic medications cause changes in cardiac rhythm and rate; therefore, monitoring of heart rate and rhythm is needed. Although it is always important to monitor respiratory rate and urine output, these assessments are not specific to amiodarone.

Which risk factors are known to contribute to atrial fibrillation? (Select all that apply.) Use of beta-adrenergic blockers Excessive alcohol use Advancing age High blood pressure Palpitations

B.C.D. The incidence of atrial fibrillation increases with age. Risk factors include hypertension, previous ischemic stroke, transient ischemic attack or other thromboembolic event, coronary heart disease, diabetes mellitus, heart failure, mitral valve disease, obesity, Caucasian race, and excessive alcohol. Beta-adrenergic blocking agents, which reduce heart rate, are used to treat atrial fibrillation. Palpitations are a symptom of atrial fibrillation, rather than a risk or a cause.

A client with atrial fibrillation with rapid ventricular response has received medication to slow the ventricular rate. The pulse is now 88 beats/min. For which additional therapy does the nurse plan? Synchronized cardioversion Electrophysiology studies (EPS) Anticoagulation Radiofrequency ablation therapy

C. Because of the risk for thromboembolism, anticoagulation is necessary. The client has stabilized; cardioversion is not needed at this time. EPS are indicated for recurring, symptomatic dysrhythmia. Ablation therapy is ordered for recurring and symptomatic atrial fibrillation.

How does the nurse recognize that atropine has produced a positive outcome for the client with bradycardia? The client states he is dizzy and weak. The nurse notes dyspnea. The client has a heart rate of 42 beats/min. The monitor shows an increase in heart rate.

D. An expected outcome after the administration of atropine is an increased heart rate. By definition, the bradydysrhythmia has resolved when the heart rate is greater than 60 beats/min. Dizziness and weakness indicate symptoms of decreased cerebral perfusion and intolerance to the bradydysrhythmia. Dyspnea indicates intolerance to the bradydysrhythmia. Atropine is used to treat bradycardia; a heart rate of 42 beats/min indicates that bradycardia is unresolved.

The nurse is caring for a client with atrial fibrillation. In addition to an antidysrhythmic, what medication does the nurse plan to administer? Heparin Atropine Dobutamine Magnesium sulfate

A. The loss of coordinated atrial contractions in atrial fibrillation can lead to pooling of blood, resulting in thrombus formation. The client is at high risk for pulmonary embolism! Thrombi may form within the right atrium and then move through the right ventricle to the lungs. In addition, the client is at risk for systemic emboli, particularly an embolic stroke, which may cause severe neurologic impairment or death. Heparin and other anticoagulants (e.g., enoxaparin [Lovenox] and warfarin [Coumadin]) are used to prevent thrombus development in the atrium and the consequence of embolization (i.e., stroke). Atropine is used to treat bradycardia and heart blocks; atrial fibrillation, unless controlled with medication, is typically rapid. Dobutamine is an inotropic agent used to improve cardiac output; it may cause tachycardia, thereby worsening atrial fibrillation. Although electrolyte levels are monitored in clients with dysrhythmia, magnesium sulfate is not used unless depletion is noted.

The nurse is caring for a client with heart rate of 143 beats/min. For which manifestations does the nurse observe? (Select all that apply.) Palpitations Increased energy Chest discomfort Flushing of the skin Hypotension

A. C. E. Tachycardia is a heart rate greater than 100 beats/min; the client with a tachydysrhythmia may have palpitations, chest discomfort (pressure or pain from myocardial ischemia or infarction), restlessness and anxiety, pale cool skin, and syncope ("blackout") from hypotension. Chest discomfort may occur because decreased time for diastole results in lower perfusion through the coronary arteries to the myocardium. Hypotension results from decreased time for ventricular filling, secondary to shortened diastole, and therefore reduced cardiac output and blood pressure. Reduced cardiac output and possible development of heart failure will cause fatigue.

The nurse is caring for a client who has developed a bradycardia. Which possible causes does the nurse investigate? (Select all that apply.) Bearing down for a bowel movement Possible inferior wall myocardial infarction (MI) Client stating that he just had a cup of coffee Client becoming emotional when visitors arrived Diltiazem (Cardizem) administered 1 hour ago

A.B.E. Excessive vagal (parasympathetic) stimulation to the heart causes a decreased rate of sinus node discharge. It may result from carotid sinus massage, vomiting, suctioning, Valsalva maneuvers (e.g., bearing down for a bowel movement or gagging), ocular pressure, or pain. Inferior wall MI is a cause of bradycardia and heart block. Calcium channel blockers such as diltiazem may cause bradycardia. Caffeine intake results in an increased heart rate. Stress, such as an emotional encounter, can result in tachycardia.

The nurse receives a report that a client with a pacemaker has experienced loss of capture. Which situation is consistent with this? The pacemaker spike falls on the T wave. Pacemaker spikes are noted, but no P wave or QRS complex follows. The heart rate is 42 beats/min, and no pacemaker spikes are seen on the rhythm strip. The client demonstrates hiccups.

B. Loss of capture occurs when the pacing stimulus (spike) is not followed by the appropriate response, either P wave or QRS complex, depending on placement of the pacing electrode. Pacemaker spikes falling on the T wave indicate improper sensing. A heart rate of 42 beats/min with no pacemaker spikes seen on the rhythm strip indicates failure to pace or sense properly; demand pacing should cause the pacemaker to intervene with electrical output when the heart rate falls below the set rate. Although the set rate is not given, this heart rate indicates profound bradycardia. Hiccups may indicate stimulation of the chest wall or diaphragm from wire perforation.

The nurse is caring for a client with acute coronary syndrome (ACS) and atrial fibrillation who has a new prescription for metoprolol (Toprol). Which monitoring is essential when administering the medication? ST segment Heart rate Troponin Myoglobin

B. The effects of metoprolol are to decrease heart rate, blood pressure, and myocardial oxygen demand. ST segment elevation is consistent with MI; it does not address monitoring of metoprolol. Elevation in troponin is consistent with a diagnosis of MI, but does not address needed monitoring for metoprolol. Elevation in myoglobin is consistent with myocardial injury in ACS, but does not address needed monitoring related to metoprolol.

The nurse is caring for a client with unstable angina whose cardiac monitor shows ventricular tachycardia. Which action is appropriate to implement first? Defibrillate the client at 200 joules. Check the client for a pulse. Cardiovert the client at 50 joules. Give the client IV lidocaine.

B. The nurse needs to assess the client to determine stability before proceeding with further interventions. If the client has a pulse and is relatively stable, elective cardioversion or antidysrhythmic medications may be prescribed. The drug of choice for stable ventricular tachycardia with a pulse is amiodarone. If the client is pulseless or nonresponsive, the client is unstable and defibrillation is used.

Which intervention provides safety during cardioversion? Setting the defibrillator at 200 joules Obtaining informed consent Setting the defibrillator to the synchronized mode Removing oxygen

C. Setting the defibrillator to the synchronized mode avoids discharging the shock during the vulnerable period on the T wave, which may cause ventricular fibrillation. Cardioversion is performed with a lower rate of energy than 200 joules. Although it is imperative to obtain informed consent, this does not improve the safety of the procedure. Oxygen should be turned off because it presents a safety issue; fire could result.

A client's rhythm strip shows a heart rate of 116 beats/min, one P wave occurring before each QRS complex, a PR interval measuring 0.16 second, and a QRS complex measuring 0.08 second. How does the nurse interpret this rhythm strip? Normal sinus rhythm Sinus bradycardia Sinus tachycardia Sinus rhythm with premature ventricular contractions

C. These are the characteristics of sinus tachycardia. A normal sinus rhythm would have a heart rate of 60 to 100 beats/min. A heart rate of less than 60 beats/min would indicate sinus bradycardia. Early QRS intervals would indicate sinus rhythm with premature ventricular contractions.

What teaching does the nurse include for a client with atrial fibrillation who has a new prescription for warfarin? "It is important to consume a diet high in green leafy vegetables." "You should take aspirin or ibuprofen for headache." "Report nosebleeds to your provider immediately." "Avoid caffeinated beverages."

C. Warfarin causes decreased ability to clot; a nosebleed could be indicative of excessive dosing. Green leafy vegetables are high in vitamin K, which may antagonize the effects of warfarin; they should be eaten in moderate amounts. Aspirin and nonsteroidal anti-inflammatory agents may prolong the prothrombin time and the international normalized ratio, causing predisposition to bleeding; these should be avoided. It is not necessary to avoid caffeine because this does not affect clotting; however, green tea may interfere with the effects of warfarin.

The nurse is caring for a client on a telemetry unit with a regular heart rhythm and rate of 60 beats/min; a P wave precedes each QRS complex, and the PR interval is 0.20 second. Additional vital signs are as follows: blood pressure 118/68 mm Hg, respiratory rate 16 breaths/min, and temperature 98.8° F. All of these medications are available on the medication record. What action does the nurse take? Administer atropine. Administer digoxin. Administer clonidine. Continue to monitor.

D. The client is displaying normal sinus rhythm. Atropine is used in emergency treatment of symptomatic bradycardia. This client has normal vital signs. Digoxin is used in the treatment of atrial fibrillation, which is, by definition, an irregular rhythm. Clonidine is used in the treatment of hypertension; a side effect is bradycardia.