Cardiac II Ch. 49
Which medication is not associated with prolongation of the QT interval? a) Dofetilide [Tikosyn] b) Sotalol [Betapace] c) Diltiazem [Cardizem] d) Dronedarone [Multaq]
C) Diltiazem [Cardizem] Diltiazem does not prolong the QT interval. Dofetilide, sotalol, and dronedarone prolong the QT interval, putting the patient at risk for torsades de pointes.
What is the most common sustained dysrhythmia among the U.S. population? a) Atrial fibrillation b) Atrial flutter c) Sustained supraventricular tachycardia (SVT) d) Ventricular premature beats (VPBs)
a) Atrial fibrillation Atrial fibrillation is the most common dysrhythmia, affecting approximately 2.6 million in the United States. This problem not only disrupts cardiac function but also carries a high risk of embolic stroke.
The nurse is administering intravenous lidocaine [Xylocaine] to a patient with a ventricular dysrhythmia. What is the priority nursing intervention to prevent a potential complication with this drug? a) Monitor the electrocardiogram (ECG) b) Obtain a complete blood count. c) Instruct to report any chest pain. d) Keep naloxone [Narcan] at the bedside.
a) Monitor the electrocardiogram (ECG). Continuous ECG monitoring is required during lidocaine infusions to evaluate cardiac response and adjust dosage accordingly and detect toxicity. Blood counts are not necessary, because lidocaine is not linked to blood dyscrasias. Lidocaine preferably is given intravenously (IV) rather than intramuscularly (IM). Sudden onset of chest pain is a sign of arterial embolism, which is a possible adverse effect of quinidine, not lidocaine. Naloxone is a reversal agent for opioids and is not used with lidocaine.
In which part of the conduction pathway in a healthy heart is the electrical impulse delayed to provide time for the blood to fill the ventricles? a) Bundle of His b) AV node c) Purkinje system d) Internodal pathway
b) AV node Impulses originate in the SA node and then travel through the AV node to reach the ventricles. The impulse is delayed at the AV node to provide time for the ventricles to fill before they contract.
A patient develops supraventricular tachycardia (SVT) and is hypotensive. Which medication should the nurse anticipate will be administered? a) Lidocaine [Xylocaine] b) Adenosine [Adenocard] c) Amiodarone [Cordarone] d) Phenytoin [Dilantin]
b) Adenosine [Adenocard] The drug of choice for terminating SVT is adenosine. Lidocaine is used for ventricular dysrhythmias; amiodarone is used for atrial and ventricular dysrhythmias; and phenytoin is used for digoxin-induced dysrhythmias.
The nurse is interpreting an electrocardiogram (ECG). Which component represents the depolarization of the ventricles? a) P wave b) QRS complex c) ST segment d) T wave
b) QRS complex An electrocardiogram has several components. The P wave is caused by depolarization in the atria; the QRS complex is caused by depolarization of the ventricles, and the T wave is caused by repolarization of the ventricles. The ST segment may be depressed in some clinical conditions.
The nurse is caring for a patient receiving amiodarone [Cordarone]. Which body system should the nurse assess for serious adverse effects of this medication? a) Musculoskeletal b) Respiratory c) Integumentary d) Gastrointestinal
b) Respiratory Pulmonary toxicity is the most serious potential adverse effect of amiodarone. It may manifest as pneumonitis or pulmonary fibrosis, with symptoms such as dyspnea, cough, and chest pain.
What should the nurse include in the discharge teaching for a patient prescribed amiodarone [Cordarone]? (Select all that apply.) a) "Take amiodarone with grapefruit juice." b) "Take the medication on an empty stomach." c) "Wear sunblock and protective clothing when you are outdoors." d) "Check your pulse daily and report excessive slowing to your healthcare provider immediately." e) "Immediately notify your healthcare provider of shortness of breath, cough, or chest pain."
c) "Wear sunblock and protective clothing when you are outdoors." d) "Check your pulse daily and report excessive slowing to your healthcare provider immediately." e) "Immediately notify your healthcare provider of shortness of breath, cough, or chest pain." "Immediately notify your healthcare provider of shortness of breath, cough, or chest pain." Correct Patients frequently experience photosensitivity reactions while taking amiodarone. To reduce this risk, patients should avoid sunlamps and wear sunblock and protective clothing when outdoors. Excessive slowing of the heart rate may indicate that the patient is experiencing sinus bradycardia or an AV block. Dyspnea, cough, and chest pain may indicate pulmonary toxicity. Grapefruit juice should be avoided, because it may increase amiodarone levels and thus the risk of toxicity. Gastrointestinal side effects of amiodarone can be reduced by taking the drug on a full stomach.
The nurse is caring for a patient prescribed quinidine [Quinaglute] for a supraventricular dysrhythmia. What is a common adverse effect of this drug? a) Constipation b) Urinary retention c) Diarrhea d) Blurred vision
c) Diarrhea Diarrhea and other gastrointestinal problems occur in approximately one-third of patients who take quinidine. This is the most common reason patients stop taking the drug.
The nurse is planning care for a patient at risk for dysrhythmias. The nurse understands that the Cardiac Arrhythmia Suppression Trial (CAST) confirmed which finding? a) Most atrial rhythm problems should be treated with medication. b) After a myocardial infarction, all dysrhythmias should be treated. c) Dysrhythmias should be treated only when they are symptomatically significant. d) Most rhythm problems result in bradydysrhythmias.
c) Dysrhythmias should be treated only when they are symptomatically significant. The Cardiac Arrhythmia Suppression Trial (CAST) confirmed that all dysrhythmia drugs have prodysrhythmic effects and can worsen existing dysrhythmias and generate new ones. In this study, patients who received encainide and flecainide to prevent rhythm problems after myocardial infarction actually had higher rates of mortality than the control group.
Amiodarone [Cordarone] is prescribed for a patient with atrial fibrillation. What is the most important nursing intervention before administering this medication? a) Document an ophthalmic examination was performed. b) Explain a dermatologic evaluation is needed c) Obtain baseline serum thyroid and liver function studies. d) Maintain NPO for transesophageal echocardiogram (TEE)
c) Obtain baseline serum thyroid and liver function studies. Amiodarone may cause hypothyroidism or hyperthyroidism and may also injure the liver. Serum thyroid and liver function levels should be assessed before treatment with amiodarone is started and periodically during treatment. Patients who develop changes in visual acuity or peripheral vision while taking amiodarone should have an ophthalmologic evaluation, but this is not necessary before starting therapy. A dermatologic examination and TEE are not necessary before initiation of amiodarone therapy. Although patients with atrial fibrillation are at risk for mural thrombus, amiodarone therapy itself does not pose a risk of systemic embolization.
In which situation is dronedarone [Multaq] contraindicated? a) PR intervals of 240 msec b) QT intervals of less than 500 msec c) Resting heart rate of 55 beats/min d) Concomitant administration of amitriptyline [Elavil]
d) Concomitant administration of amitriptyline [Elavil] Drugs and supplements that prolong the QT interval (eg, phenothiazines, tricyclic antidepressants, amitriptyline, class I and class III antidysrhythmics) can intensify dronedarone-induced QT prolongation, thereby increasing the risk of torsades de pointes. These drugs are contraindicated for use with dronedarone. Dronedarone is contraindicated when the PR intervals are greater than 280 msec, the QT interval is greater than 500 msec, and the heart rate is less than 50 beats/min
A nurse is caring for a patient receiving dronedarone [Multaq] for treatment of atrial fibrillation. What electrocardiogram (ECG) change indicates an adverse effect of this medication? a) Previously upright T waves now are inverted. b) Previously rounded, upright P waves now are notched. c) ST segments previously on the baseline now are depressed. d) The QT-interval measurement changes from 400 to 520 msec.
d) The QT-interval measurement changes from 400 to 520 msec. Dronedarone prolongs the QT interval by about 10 msec. A QT-interval measurement of 400 msec in a normal heart rate (60 to 100 beats/min) is normal. Prolongation to 520 msec would increase the risk of torsades de pointes. Newly inverted T waves and ST-segment depression can be signs of ischemia or infarction and warrant further investigation through analysis of troponin levels. Notched P waves can be a sign of valvular heart disease and are unrelated to treatment with dronedarone.
