Ch. 45 Antiarrhythmic agents

A client receives lidocaine by intramuscular injection. The nurse would expect the drug to begin to exert its therapeutic effects within which time frame?

5 to 10 minutes Explanation:Lidocaine, when given by intramuscular injection, has an onset of action between 5 to 10 minutes and peaks in 5 to 15 minutes.

A client experiencing a ventricular arrhythmia has received a bolus of lidocaine. What is the recommended rate for continuous infusion of lidocaine IV now prescribed for this client?

1 to 4 mg/min Explanation:A continuous infusion of lidocaine IV after a bolus is 1 to 4 mg/min. The administration of 0.25 to 0.75 mg/min would be too small of a dosage. The administration of 10 to 20 or 6 to 8 mg/min would be too large.

After the nurse has administered a bolus of lidocaine, the nurse should run a continuous infusion at which rate?

1-4 mg/min Explanation:Lidocaine may be delivered at 1 to 4 mg/min after a bolus.

At what digoxin level would the care team first suspect that the client is experiencing the therapeutic effects of the medication?

1.5 ng/mL Explanation:The therapeutic serum digoxin level is 0.8 to 2.0 ng/mL. Levels above that would indicate toxicity, and those below would not yet be therapeutic.

A patient is receiving milrinone IV. The nurse would administer the bolus over which time frame?

10 minutes Explanation:Milrinone is administered by IV bolus over 10 minutes.

A patient receives lidocaine IV. The nurse would expect the drug to exert its effects for how long?

10 to 20 minutes Explanation:Lidocaine when given IV has a duration of action of 10 to 20 minutes.

A patient is receiving procainamide intravenously. The nurse understands that the initial dose should run over which time frame?

25 to 30 minutes Explanation:Procainamide, when given IV, is administered initially over 25 to 30 minutes.

The primary health care provider prescribes sotalol (Betapace) 80 mg BID orally. The drug is available in 40 mg tablets. The nurse will administer how many tablets in 24 hours?

4 Explanation:80mg X 2 (BID) = 160 mg total daily dose 160 mg / 40 mg = 4 tablets in 24 hours

The nurse is preparing to administer quinidine intravenously. At what rate will the nurse administer this medication?

1 mL/min Explanation:Quinidine is administered at a rate of 1 mL/min.

A client is prescribed sotalol. Which instruction would be most important?

"Be sure to take the drug on an empty stomach." Explanation:Sotalol absorption is decreased by the presence of food, so it should be taken on an empty stomach to maximize absorption. There is no need to sit up after taking the drug. Antacids would interfere with the absorption. Holding the drug if the pulse rate is less than 60 beats/minute applies to digoxin.

A client diagnosed with heart disease is prescribed an antiarrhythmic drug. Further teaching is needed when the client makes which statement?

"I know I must take my medication every day for my heartbeat to be fixed." Explanation:Antiarrhythmic drugs do not cure disease. Along with lifestyle changes, they can improve the quality of life. Adherence to the drug regimen is important. Following the directions on drug labels is also important. The client should check with the primary care provider before taking any nonprescription drug, supplement, or herbal preparation.

A client diagnosed with a cardiac dysrhythmia will not require medication therapy. The client expresses concern about the lack of proposed treatment. What response should the nurse provide to best address the client's concern?

"The dysrhythmia you have isn't interfering with getting oxygen to your body tissues so there is no need to treat it." Explanation:Dysrhythmias become significant when they interfere with the perfusion of body tissues as evidenced by symptoms. When perfusion is impaired, medication therapy is prescribed. Attempting to assure the client that the cardiologist will prescribe medication when appropriate does not address the client's current concerns. None of the remaining options provide accurate information regarding medication therapy for dysrhythmias.

Which patient would a nurse determine to be at the greatest risk for quinidine toxicity?

A 44-year-old man diagnosed with cardiac insufficiency Explanation:The 44-year-old man with cardiac insufficiency is at risk for quinidine toxicity because the total clearance and volume of distribution of the drug will be decreased. This decrease may result in greater risk for adverse effects or in less substantial therapeutic effects than expected. The drug is contraindicated in patients with complete heart block and myasthenia gravis. Quinidine is in pregnancy category C, but pregnancy does not increase the risk of toxicity.

When educating a group of nursing students on the mechanism of the action of various anti-arrhythmic drugs, the nurse identifies which drugs as inhibiting the beta-adrenergic receptors of the heart and the kidney?

Acebutolol Explanation:The nurse should inform the nursing students that acebutolol acts by inhibiting the beta-adrenergic receptors of the heart and the kidney. Propafenone and amiodarone appear to act directly on the cardiac cell membrane, and on the beta-adrenergic receptors of the heart and the kidney. Disopyramide acts by decreasing the depolarization of the myocardial fibers, and not the beta-adrenergic receptors of the heart and the kidney.

After reviewing antiarrhythmic drugs, a group of nursing students demonstrate understanding of the drugs when they identify which as a class II antiarrhythmic? Select all that apply.

Acebutolol Propranolol Acebutolol and propranolol are class II antiarrhythmics. Amiodarone and ibutilide are class III antiarrhythmic drugs. Verapamil is a calcium channel blocker.

A patient develops supraventricular tachycardia. Vagal maneuvers were tried but were unsuccessful. Drug therapy is initiated. Which agent would the nurse expect to be used?

Adenosine Explanation:The drug of choice for treating supraventricular tachycardia when vagal maneuvers have been ineffective is adenosine because it has a short duration of action and is associated with few adverse effects.

When describing the action of antiarrhythmics, which effect would most likely be included?

Alteration in conductivity Explanation:Antiarrhythmic agents alter the conductivity or suppress automaticity of the heart.

After teaching group of students about antiarrhythmic agents, the instructor determines that the teaching was successful when the students identify which of the following as examples of class III antiarrhythmics? Select all that apply.

Amiodarone Dofetilide Sotalol Ibutilide Amiodarone is a class III antiarrhythmic. Dofetilide is a class III antiarrhythmic. Sotalol is a class III antiarrhythmic. Ibutilide is a class III antiarrhythmic. Flecainide is a class 1C antiarrhythmic. Verapamil is a class IV antiarrhythmic.

In some cases, low-dose amiodarone may be used to prevent recurrence of what cardiac disorder?

Atrial fibrillation Explanation:Low-dose amiodarone may be a pharmacologic choice for preventing recurrent atrial fibrillation after electrical or pharmacologic conversion. Potassium channel blockers such as amiodarone prolong duration of the action potential, slow repolarization, and prolong the refractory period in both the atria and ventricles. Potassium channel blockers are not effective in preventing valvular disorders, ventricular hypertrophy, or angina.

The client taking digoxin (Lanoxin) has developed an infection. What medication can the nurse safely administer to this client?

Azithromycin Explanation:Zithromax may be given without impacting the effects of digoxin. There is a risk of increased therapeutic effects and toxic effects of digoxin if it is taken with verapamil, amiodarone, quinidine, quinine, erythromycin, tetracycline, or cyclosporine. If digoxin is combined with any of these drugs, it may be necessary to decrease the digoxin dose to prevent toxicity. If one of these drugs has been part of a medical regimen with digoxin and is discontinued, the digoxin dose may need to be increased.

A client receiving warfarin is prescribed disopyramide. The nurse would monitor for signs and symptoms of what as most important?

Bleeding Explanation:The combination of disopyramide with warfarin increases the client's risk for bleeding. The combination of disopyramide with warfarin does not promote renal dysfunction. The combination of disopyramide with digoxin or beta blockers increases the client's risk for the development of arrhythmias.

Which statement would be true about the mechanism of action of class II antiarrhythmic agents?

Block the stimulation of the adrenergic receptors Explanation:Class II antiarrhythmic drugs block adrenergic receptors (beta-blockers), producing antisympathetic effects that slow the heart rate, lengthen the time needed for conduction, and increase the force of contraction. The effect seen with class II antiarrhythmic drugs is depression of phase 4 of depolarization.

When describing the action of class II antiarrhythmics, which would the nurse include?

Blockage of beta receptors in the heart and kidneys Explanation:Class II antiarrhythmics are beta-adrenergic blockers that block the beta receptor sites in the heart and kidneys. Membrane stabilization and phase 0 depression occurs with class I antiarrhythmics. Blockage of potassium channels during phase 3 of the action potential occurs with class III antiarrhythmics. Blockage of calcium ion movement occurs with class IV antiarrhythmics.

A patient with type 1 diabetes is prescribed acebutolol. What would be most important to monitor?

Blood glucose levels Explanation:The combination of insulin used for type 1 diabetes and acebutolol increases the patient's risk for hypoglycemia necessitating close monitoring of the patient's blood glucose levels.

A breast-feeding woman is prescribed a Class 3 antiarrhythmic. What information should the nurse provide to the client regarding the safety of the breast-feeding while taking this medication?

Breast-feeding must be discontinued and other forms of feeding should be introduced. Explanation:The safety for the use of antiarrhythmic drugs during pregnancy has not been established. They should not be used in pregnancy unless the benefit to the mother clearly outweighs the potential risk to the fetus. The drugs enter breast milk, and some have been associated with adverse effects on the neonate. Class I, III, and IV agents should not be used during lactation; if they are needed, another method of feeding the baby should be used.

The nurse would instruct a client receiving acebutolol about which adverse effect?

Bronchospasm Explanation:Bronchospasm is a possible adverse effect of acebutolol, a class II antiarrhythmic. Other effects include hypotension, decreased libido, and decreased exercise tolerance.

Lidocaine is the prototype of class IB antiarrhythmics used for treating serious ventricular arrhythmias associated with what conditions? (Select all that apply.)

Cardiac catheterization Cardiac surgery Digitalis-induced ventricular arrhythmias Lidocaine is the prototype of class IB antiarrhythmics used for treating serious ventricular arrhythmias associated with acute myocardial infarction, cardiac catheterization, or cardiac surgery and digitalis-induced ventricular arrhythmias. It is not intended for use with clients experiencing cardiac arrest.

A client with diabetes is given a prescription for propranolol (Inderal) to treat a cardiac arrhythmia. Which instruction by the nurse would be appropriate?

Check blood glucose once or twice daily. Explanation:Propranolol can cause hyperglycemia, and clients with diabetes should be advised to check blood sugar once or twice daily and report any elevated blood glucoses to the health care provider. Advising the client to stop taking diabetes medications or to double dose is an inappropriate response. All medications should be continued as prescribed unless changed by the provider. Eating a diet high in carbohydrates can cause increases in blood sugar, and not an appropriate diet.

A nurse is preparing to administer flecainide. The nurse identifies this drug as being classified as which type of antiarrhythmic?

Class IC Explanation:Flecainide is a class IC antiarrhythmic. Disopyramide is a class IA drug. Lidocaine is a class IB drug. Beta-adrenergic blockers are class II drugs.

A client is admitted to the emergency department with a ventricular arrhythmia associated with an acute myocardial infarction. What assessment should the nurse make prior to administering a bolus of lidocaine IV?

Determine if the client has had a reaction to local anesthesia. Explanation:Lidocaine is contraindicated in clients allergic to local anesthetic agents. It is important to determine if the client has been administered lidocaine in the past, but it is imperative to ascertain any untoward effects. The medication will be administered intravenously, so it is not necessary to assess the client's ability to swallow. However, swallowing can be impaired after administration and should be assessed. It is not necessary to do a nutritional assessment at this time.

A client with a history of severe renal failure has been placed on digoxin for atrial dysrhythmia. Based on the client's history, the nurse anticipates which action?

Digoxin dose will need to be reduced. Explanation:In older adults and in the presence of renal failure, therapeutic serum levels are 0.5 to 1.3 ng/mL. Toxicity may occur at virtually any serum level. Because most of the digoxin is excreted unchanged by the kidneys, dosage must be reduced in the presence of renal failure to prevent drug accumulation and toxicity. The remainder is metabolized or excreted by nonrenal routes. Nothing in the scenario indicates a need to stop the drug, and there is no need to add furosemide or potassium.

The health care provider has prescribed a class IV calcium channel blocker for a client diagnosed with acute supraventricular tachycardia. Which drug does this nurse expect to be prescribed?

Diltiazem Explanation:Calcium channel blockers obstruct the movement of calcium into conductive and contractile myocardial cells by inhibiting the influx of calcium through its channels, causing a slower conduction through the SA and AV nodes. Diltiazem is administered intravenously to treat acute supraventricular tachycardia. Bethanechol is used to treat neurogenic bladder. Chlorambucil is an antineoplastic agent used to treat chronic lymphocytic leukemia. Midazolam hydrochloride is administered to reduce anxiety.

The nurse is visiting the home of a client who is prescribed antidysrhythmic medication. The nurse will teach the client to report which possible adverse effect?

Dizziness Explanation:Clients receiving chronic antidysrhythmic drug therapy are likely to have significant cardiovascular disease. With each visit, the home care nurse needs to assess the client's physical, mental, and functional status and evaluate pulse and blood pressure. In addition, clients and caregivers should be taught to report symptoms (e.g., dizziness or fainting, chest pain) and to avoid over-the-counter agents unless discussed with a health care provider.

The nurse is visiting the home of a client who is prescribed antidysrhythmic medication. The nurse will teach the client to report which possible adverse effect?

Dizziness Explanation:Clients receiving chronic antidysrhythmic drug therapy are likely to have significant cardiovascular disease. With each visit, the home care nurse needs to assess the client's physical, mental, and functional status and evaluate pulse and blood pressure. In addition, clients and caregivers should be taught to report symptoms (e.g., dizziness or fainting, chest pain) and to avoid over-the-counter agents unless discussed with a health care provider.

A client is prescribed propranolol (Inderal). Which condition in the client's history may affect the treatment regimen?

Elevated glucose Explanation:The client with diabetes may experience elevated glucose levels while taking propranolol, and the insulin or oral hypoglycemic drug dosages may need to be adjusted. Nausea, diarrhea, and dizziness are all adverse reactions to propranolol.

Which of the following antiarrhythmics would have little effect on the duration of the action potential?

Flecainide Explanation:Flecainide is a Class 1C drug that markedly depresses phase 0, with a resultant extreme slowing of conduction, but has little effect on the duration of the action potential. Procainamide is a Class 1A drug that depresses phase 0 of the action potential and prolongs the duration of the action potential. Lidocaine is a Class 1B drug that depresses phase 0 somewhat and actually shortens the duration of the action potential. Propranolol is a Class II drug that causes a depression of phase 4 of the action potential.

Which arrhythmia would the nurse identify as being related to an alteration in conduction through the heart muscle?

Heart block Explanation:Heart block is an arrhythmia related to an alteration in conduction through the muscle. Premature atrial contraction, atrial flutter, and ventricular fibrillation are arrhythmias due to stimulation from an ectopic focus.

A male client takes his pulse rate before taking his regular daily dose of digoxin and finds his pulse to be 52 beats/min. Which would the client do next?

Hold the dose and retake the pulse in 1 hour. Explanation:If the pulse rate is below 60 beats/minute, the client should hold the dose and recheck his pulse in 1 hour. Then, if the pulse is still low, he make a note of it, withhold the drug, and notify the prescriber. The prescriber can then determine the next action.

The nurse is assessing a client and suspects that the client is experiencing a arrhythmia. What client assessments would support this condition? (Select all that apply.)

Hypotension Mental confusion Shortness of breath Clients who are experiencing a arrhythmia often experience oliguria, hypotension, mental confusion or syncope, or shortness of breath. Leg pain is not a symptom of arrhythmia.

There are four primary classes of antidysrhythmic drugs. What class consists primarily of potassium channel blockers?

III Explanation:The class III antiarrhythmics are primarily potassium channel blockers. Class I drugs are sodium channel blockers; class II drugs are beta-adrenergic blockers; and class IV drugs are calcium channel blockers.

A client has been prescribed IV amiodarone for emergency treatment of a serious ventricular arrhythmia. The nurse monitors the client's ECG anticipating a noted change how long after the medication is delivered?

Immediately Explanation:The onset of IV amiodarone is immediate with the peak occurring in 20 minutes and a duration of 6-8 hours.

A client is administered diltiazem IV, followed by propranolol IV. The nurse should assess for what potential side effect of this medication combination?

Impaired myocardial contractility Explanation:If diltiazem is used with propranolol or digoxin, it is necessary to exercise caution to avoid further impairment of myocardial contractility. The administration of IV diltiazem and propranolol will not produce hypertensive crisis, anaphylaxis, or valve regurgitation.

An ED patient presents with dyspnea, tachycardia, and chest pain. The patient has a history of cardiomyopathy. The nursing assessment reveals hypotension with an apical pulse of 134 bpm. What would the nurse conclude might be causing the symptoms?

Inadequate cardiac output Explanation:Symptoms presenting suggest a cardiac condition. A diseased heart may not be able to maintain an adequate cardiac output with heart rates below 60 bpm above 120 bpm.

The nurse is administering quinidine to a client who is also taking digoxin. The nurse will assess this client for which important adverse effect?

Increased digoxin level Explanation: The nurse would assess this client for digoxin toxicity because quinidine and digoxin interact, leading to an increased digoxin level.

A patient is prescribed esmolol for treatment of supraventricular tachycardia. The nurse would expect to administer this drug by which route?

Intravenous Explanation:Esmolol is available only for IV administration.

Lidocaine (Xylocaine) is available in a variety of dosage forms. How should a nurse administer lidocaine to a client with a ventricular arrhythmia?

Intravenously Explanation:The nurse should administer lidocaine intravenously for the treatment of ventricular arrhythmias.

A client is admitted to the emergency department in ventricular fibrillation. The client is administered amiodarone hydrochloride. What is the major effect of this medication?

It slows the conduction through the AV node. Explanation:The major effect of amiodarone is that it slows the conduction through the AV node and prolongs the refractory period. It produces smooth muscle, not skeletal muscle, relaxation. It prolongs the refractory period; it does not inhibit the increase of the refractory period. It blocks the effects of the sympathetic nervous system instead of stimulating it.

An adult client with a history of coronary artery disease is undergoing cardiac catheterization. What drug should the nurse most likely prepare for administration when the client suddenly begins exhibiting ventricular tachycardia?

Lidocaine Explanation:Lidocaine is the drug of choice for treating serious ventricular arrhythmias associated with acute myocardial infarction, cardiac catheterization, cardiac surgery, and digitalis-induced ventricular arrhythmias since it decreases myocardial irritability (automaticity) in the ventricles. Digoxin, MgSO4, and epinephrine are not used in this clinical situation since none affect myocardial irritability in this way.

The nurse is caring for a client who has been prescribed quinidine. The nurse should advocate for a lower-than-normal dose if the client has a history of what medical diagnosis?

Liver disease Explanation:Hepatic impairment increases the plasma half-life of several antidysrhythmic drugs, including quinidine, and clients with hepatic impairment usually receive a reduced dosage. The pathophysiologies of the other conditions would not affect the half-life of quinidine since they do not affect drug metabolism.

A critical care nurse is caring for a client after open-heart surgery. What nursing intervention would the nurse initiate to help detect life-threatening arrhythmias and manage and minimize any that occur?

Monitor cardiac rhythm continuously. Explanation:The nurse should monitor cardiac rhythm continuously. Cardiac monitors display real-time heart rate and rhythm and alert the nurse to potentially life-threatening arrhythmias. Monitoring blood pressure continuously and palpating the client's pulse do not help detect life-threatening arrhythmias. Providing supplemental oxygen helps maintain adequate cardiac output and does not help detect life-threatening arrhythmias.

A client is prescribed disopyramide. The nurse would expect to administer this drug by which route?

Oral Explanation:Disopyramide is administered orally.

A client is started on antiarrhythmic therapy to treat atrial fibrillation. The nurse caring for this client knows which occurrence is a potential side effect of this medication?

Other arrhythmias Explanation:One problem with all antiarrhythmics is their ability to modify the rhythm of the heart; they can cause a new arrhythmia or exacerbate the arrhythmia that they are treating. This adverse effect is termed proarrhythmia.

A client is started on antiarrhythmic therapy to treat atrial fibrillation. The nurse caring for this client knows which occurrence is a potential side effect of this medication?

Other arrhythmias Explanation:One problem with all antiarrhythmics is their ability to modify the rhythm of the heart; they can cause a new arrhythmia or exacerbate the arrhythmia that they are treating. This adverse effect is termed proarrhythmia.

A patient with cardiac arrhythmia is prescribed verapamil. Which of the following possible adverse effects should the nurse inform the patient about?

Peripheral edema Explanation:The nurse should inform the patient that peripheral edema could be an adverse effect to verapamil therapy. Diarrhea, hyperactivity, and hypertension are not adverse effects associated with verapamil therapy. Other adverse effects associated with verapamil are constipation, mental depression, and hypotension.

What is the safest precaution to take when administering an antiarrhythmic drug intravenously (IV)? Choose the BEST response.

Place the client on a cardiac monitor. Explanation:Cardiac monitoring is recommended when drugs are given intravenously and allows for observation of ECG activity, since severe bradycardia and hypotension can occur. Relocating the client does not assess the client's heart activity. Counting the apical pulse before administration is appropriate, but cardiac monitoring allows for continued assessment throughout administration and beyond. Administering the drug through new IV line may be appropriate, but this action does not provide continued cardiac assessment.

A client is receiving inamrinone. Which would be most important for the nurse to monitor?

Platelet count Explanation:Although renal function studies may be appropriate to monitor and evaluate the need for possible dosage changes, inamrinone is associated with thrombocytopenia. Therefore, it would be most important for the nurse to monitor the client's platelet count. Inamrinone is not associated with changes in pulmonary function or white blood cell counts.

A patient is admitted to the cardiology unit of a health care facility for ventricular arrhythmia. In which condition can an anti-arrhythmic drug be safely administered?

Premature ventricular contraction Explanation:The patient can be safely administered an anti-arrhythmic drug if the patient has premature ventricular contractions. Aortic stenosis, third-degree heart block, and severe congestive heart failure are contraindications for the use of anti-arrhythmic drugs.

A client is receiving adenosine for treatment of supraventricular tachycardia. The nurse understands that this drug results in:

Prolonged refractory period Explanation:denosine slows conduction through the atrioventricular node, prolongs the refractory period, and decreases automaticity through the atrioventricular node. Digoxin used as an antiarrhythmic slows calcium from leaving the cell, prolonging the action potential and slowing conduction and heart rate.

Which antiarrhythmic drug is also used to treat a myocardial infarction?

Propranolol (Inderal) Explanation:Propranolol has reduced the risk of death and repeated myocardial infarction in those surviving the acute phase of a myocardial infarction.

What important information should be included in a client's education about potential adverse effects of propranolol?

Propranolol may cause bronchial and laryngospasms. Explanation:Bronchospasm and laryngospasm are the most serious adverse respiratory effects of propranolol and warrant careful monitoring. Restless legs, agitation, and hypertension are not noted adverse effects.

A patient is receiving an intravenous infusion of amiodarone for treatment of ventricular fibrillation. Which is the most serious adverse effect of the medication?

Pulmonary toxicity Explanation:Pulmonary toxicity is a potentially fatal adverse effect of amiodarone. Other potentially fatal effects associated with the drug are liver disease and exacerbation of the underlying arrhythmia. Vomiting, hypotension, and optical neuropathy are all potential adverse effects of the drug. Vomiting and optical neuropathy, however, are not life-threatening, and hypotension can typically be controlled by reducing the infusion rate of amiodarone.

A patient on anti-arrhythmic drug therapy reports nausea, vomiting, abdominal pain, diarrhea, and a ringing sensation in the ears. Which drug should the nurse consider as the cause for these adverse effects?

Quinidine Explanation:The nurse should consider the drug Quinidine as the cause for these adverse effects. Quinidine toxicity is called cinchonism. Some of its symptoms include ringing in the ears (tinnitus), hearing loss, headache, nausea, vomiting, abdominal pain, dizziness, vertigo, and light-headedness. Lidocaine, flecainide, and procainamide do not cause tinnitus or hearing loss as adverse effects.

A client has been prescribed disopyramide (Norpace) to treat a tachyarrhythmia. Which factor would necessitate that the dose be reduced?

Renal impairment Explanation:Disopyramide is excreted in the kidneys and the liver in almost equal proportions. The dose must be reduced in renal insufficiency based on creatinine clearance. The dose does not need to be reduced in immobility, hypertension, or chronic diarrhea.

A client has a complex cardiac history that includes recurrent ventricular fibrillation. After the failure of more conservative treatments, the care team has introduced oral amiodarone. What assessments should be prioritized by the nurse who is providing care for this client?

Respiratory assessment Explanation:Amiodarone has several adverse effects that are potentially fatal. Pulmonary toxicity is the most important of these serious adverse effects. Consequently, the nurse should prioritize respiratory assessments over musculoskeletal or neurological assessments.

Which would be a contraindication for the use of a class II antiarrhythmic?

Sinus bradycardia Explanation:Class II antiarrhythmics are contraindicated in sinus bradycardia but should be used cautiously in clients with diabetes, thyroid dysfunction, and hepatic dysfunction.

The nurse administering a Class I antiarrhythmic drug understands that the action of this drug is to:

Stabilize or anesthetize the membranes of cardiac cells Explanation: Class I antiarrhythmics (sodium channel blockers) stabilize or anesthetize the membranes of cardiac cells. Class II antiarrhythmics (beta-adrenergic blockers) indirectly block calcium channels. Class III antiarrhythmics (potassium channel blockers) prolong repolarization. Class IV antiarrhythmics (calcium channel blockers) depress depolarization and lengthen repolarization.

What would the nurse teach the client to monitor for when beginning an antidysrhythmic drug regimen?

Syncope Explanation:Monitor for adverse effects, which include sedation, hypotension, cardiac arrhythmias, respiratory depression, and CNS effects. The client would not need to monitor for diarrhea, gastric upset, or dry mouth.

A client diagnosed with a dysrhythmia has not responded appreciably to treatment with oral propranolol. When the medication is discontinued, what instruction should the nurse provide the client to maximize safety?

Taper down the propranolol dose over a period of 2 weeks. Explanation:It is essential that propranolol not be discontinued abruptly after long-term therapy; a hypersensitivity to catecholamines may have developed, exacerbating ventricular dysrhythmia. Gradual tapering over a 2-week period, with client monitoring, is necessary. Replacement with a different beta-blocker is not necessarily indicated. Propranolol is not administered by the IM route. Monitoring alone is not sufficient treatment in this situation.

A nurse is assigned to care for a client who has to be administered an antiarrhythmic drug. Under what conditions would its use be contraindicated? Select all that apply.

The client has hypotension. The client has aortic stenosis. The client has cardiogenic shock. The nurse knows that antiarrhythmic drugs are contraindicated in clients with hypotension, aortic stenosis, and cardiogenic disturbances. Arrhythmic drugs are used cautiously and not contraindicated in clients with electrolyte disturbances and renal or hepatic disease.

After successful treatment for a myocardial infarction, a 69-year-old man has developed a ventricular arrhythmia. His care team has opted for treatment with a Class II antiarrhythmic. The nurse would understand that this client is likely to be prescribed:

acebutolol. Explanation:Class II antiarrhythmics are the beta blockers. Of the other numerous drugs in this class, only acebutolol and esmolol are approved as Class II antiarrhythmics, though other beta blockers are used off label. Lidocaine is a Class IB drug; amiodarone is a Class III antiarrhythmic, and verapamil is a Class IV drug.

After successful treatment for a myocardial infarction, a 69-year-old man has developed a ventricular arrhythmia. His care team has opted for treatment with a Class II antiarrhythmic. The nurse would understand that this client is likely to be prescribed:

acebutolol. Explanation:Class II antiarrhythmics are the beta blockers. Of the other numerous drugs in this class, only acebutolol and esmolol are approved as Class II antiarrhythmics, though other beta blockers are used off label. Lidocaine is a Class IB drug; amiodarone is a Class III antiarrhythmic, and verapamil is a Class IV drug.

A 75-year-old client presents to the physician with a cardiac arrhythmia. The physician chooses to treat the arrhythmia because of symptoms related to:

circulatory impairment. Explanation:Cardiac arrhythmias are common in older adults, but in general only those causing symptoms of circulatory impairment should be treated with antidysrhythmic drugs.

After teaching a group of students about possible hypersensitivity reactions associated with milrinone, the students demonstrate a need for additional teaching when they identify:

cellulitis. Explanation:Cellulitis is not an associated hypersensitivity reaction that occurs with milrinone.

An adult client with a long-standing arrhythmia has been taking oral propranolol for the last several months, resulting in acceptable symptom control. What is a priority teaching point for the nurse to communicate to this client?

The importance of not stopping the medication abruptly Explanation:Clients need to realize that they should not stop taking propranolol abruptly because this action can cause the arrhythmia to worsen. There is no need to restrict potassium intake, to avoid antacids, or to measure the radial pulse prior to each dose of propranolol.

A nurse is the cardiac care unit is preparing to hang an intravenous dose of dofetilide (Tikosyn) for a client who has just been admitted. What is the most likely goal of this intervention?

To convert the client's atrial fibrillation to normal sinus rhythm Explanation:Dofetilide is used to convert clients in atrial fibrillation to normal sinus rhythm and maintain them in sinus rhythm. This drug is not used in the treatment of bradycardia, heart failure, or ventricular arrhythmias.

The teaching plan for a client taking amiodarone should include which instruction?

Use a reliable form of birth control while taking this medication. Explanation:Amiodarone is a pregnancy category D drug. Because of a specific enzyme reaction, grapefruit or its juice should not be taken with amiodarone or calcium channel blockers. Urinary retention is an adverse reaction and should be reported to the health care provider. Drowsiness may occur, and the client should be instructed not to drive and to avoid hazardous tasks if drowsy.

The nurse evaluates an improvement in the client's heart failure (HF) status based on what assessment finding?

Using fewer pillows to sleep Explanation:The degree of HF is often calculated by the number of pillows required to get relief (e.g., one-pillow, two-pillow, or three-pillow orthopnea). Fluid overload is associated with HF so skin turgor is not an indicator of improvement. Regular heart rate and normal cognition can be found with acute flare-ups of HF so these findings would not indicate improvement.

A female patient diagnosed with chronic atrial flutter has been prescribed verapamil in conjunction with digoxin to control ventricular rate. To enhance the therapeutic effect of the drug, the nurse will instruct the patient to:

avoid grapefruit and grapefruit juice. Explanation:The patient should be instructed to avoid grapefruit and grapefruit juice because they may increase the verapamil level. The patient should also abstain from using alcohol and aspirin while taking this medication. Encouraging the patient to increase her fluid intake and include fresh fruit and fiber in her diet can help prevent constipation. Taking the medication with meals would not enhance its effect.

The nurse notes that a client's current medications include both diltiazem for a dysrhythmia and atazanavir. The nurse should recognize the need to closely monitor which client assessment datum?

blood pressure Explanation:When caring for clients who are receiving diltiazem, the nurse monitors carefully for changes in blood pressure and cardiac rhythm as well as output. Checking the blood pressure is especially important if the client is taking atazanavir concurrently since the combination tends to produce hypotension. There is no need for increased monitoring of oxygenation, peripheral pulse, or level of consciousness.

When describing the drugs classified as class IV antiarrhythmics, the nurse would identify these as:

calcium channel blockers. Explanation:Class IV antiarrhythmics include calcium channel blockers. Beta blockers are class II antiarrhythmics. Cardiac glycosides, such as digoxin may be used as an antiarrhythmic, but are not classified as class I, II, III, or IV. Vasodilators are not used as antiarrhythmics.

A stable client with atrial flutter is symptomatic from the arrhythmia. The health care provider administers dofetilide IV in an attempt to:

convert the arrhythmia to a sinus rhythm. Explanation:Dofetilide is used to promote conversion to sinus rhythm, while medications such as diltiazem, verapamil, and digitalis are used to slow the ventricular rate.

The health care provider orders quinidine for a client who is receiving a common treatment for atrial fibrillation. The nurse would monitor this client for:

digoxin toxicity. Explanation:Quinidine interacts with digoxin (classically prescribed for atrial fibrillation , possibly leading to increased digoxin levels and digoxin toxicity. The effects of digoxin, not quinidine, are increased. Bleeding may occur if class I antiarrhythmics are given with oral anticoagulants such as warfarin. Renal dysfunction is unrelated to the use of both drugs.

Propranolol is ordered for a client who has a cardiac arrhythmia. It will be important for the nurse to determine if the person has a history of:

hypersensitivity to beta blockers. Explanation:Propranolol would be contraindicated in a patient with hypersensitivity to beta blockers since it blocks the beta-adrenergic receptor sites. For the same reason, it would not be contraindicated in chronic heart failure secondary to a tachyarrhythmia, treatable with beta blockers. It would also not be contraindicated in a client with an idiosyncratic reaction to cinchona derivatives or in a client with hypersensitivity to sulfonylureas because it is not a cinchona derivative and does not contain sulfonylurea.

A patient has been prescribed inamrinone. The nurse knows that this drug works by:

increasing cyclic adenosine monophosphate (cAMP). Explanation:By blocking the enzyme phosphodiesterase, phosphodiesterase inhibitors such as inamrinone increase myocardial cell cAMP. The resulting increase in cellular calcium levels leads to a stronger myocardial contraction and prolongs the effects of sympathetic stimulation.

A 70-year-old woman with a history of atrial fibrillation takes digoxin and verapamil to control her health problem. Verapamil achieves a therapeutic effect by:

inhibiting the movement of calcium ions across the cardiac muscle cell membrane. Explanation:Verapamil acts by inhibiting the movement of calcium ions across the cardiac and arterial muscle cell membrane. It works preferentially in "slow response" myocardial tissue, such as the SA and AV nodes. Beta blockers inhibit adrenergic receptors and Class IB antiarrhythmics are among the drugs that decrease sodium and potassium conduction. Lidocaine weakens phase 4 diastolic depolarization and decreases the action potential duration and the effective refractory period of Purkinje fibers and ventricular muscle.

What is the primary goal of antidysrhythmic drug therapy for a client who has been successfully cardioverted?

maintenance of normal sinus rhythm (NSR) Explanation:Maintaining NSR after conversion from atrial fibrillation or atrial flutter is one of the indications for antidysrhythmic drug therapy. This is not achieved solely by increasing contractility. Increased tissue perfusion is a valid goal, but increased blood pressure may or may not be desirable. Clinicians use drugs not just to suppress dysrhythmia but to prevent or relieve symptoms or prolong survival.

The nurse's subsequent cardiac assessments and monitoring of a client prescribed disopyramide should be planned in the knowledge that this drug increases the client's risk for developing what health problem?

new arrhythmias Explanation:For disopyramide, the Food and Drug Administration (FDA) has issued a black box warning because of the drug's known prodysrhythmic properties. It is not specifically linked to chest pain, valvular regurgitation, or renal failure.

The risk for which outcome is increased when a client experiences a drug-to-drug interaction while on amiodarone therapy?

new dysrhythmias Explanation:When oral amiodarone is used long term, it increases the effects of numerous drugs, worsening existing dysrhythmias or producing new dysrhythmias. Drugs that interact with amiodarone include beta-blockers, oral anticoagulants, digoxin, and phenytoin.

To maximize absorption of digoxin, the nurse would instruct the patient to take the drug:

on an empty stomach. Explanation:Digoxin is absorbed best on an empty stomach.

Initiation of the heart's electrical impulses depends predominantly on what electrolyte movement? Select all that apply.

potassium ions out of a myocardial cell sodium ions into a myocardial cell calcium ions into a myocardial cell Explanation:Initiation of an electrical impulse depends predominately on the movement of sodium and calcium ions into a myocardial cell and movement of potassium ions out of the cell.

A 92-year-old male client is being sent home on disopyramide for a ventricular arrhythmia. The client asks why he must continue to take this drug. The nurse's best response would be that a ventricular arrhythmia may:

result in death. Explanation:These drugs are indicated for the treatment of potentially life-threatening ventricular arrhythmias and should not be used to treat other arrhythmias because of the risk of a proarrhythmic effect. Generally, a ventricular arrhythmia does not cause blood clots in the legs, result in the atria beating independently, or cause edema in extremities.

The results of the CAST study have limited the use of antiarrhythmics to:

short-term use to treat life-threatening ventricular arrhythmias. Explanation:The CAST study, a large research study run by the National Heart and Lung Institute, found that long-term treatment of arrhythmias may have a questionable effect on mortality, and in some cases actually lead to increased cardiac death, which is the basis for the current indication for antiarrhythmics (short-term use to treat life-threatening ventricular arrhythmias).