Heart Failure

Heart Failure

Heart failure, cardiac failure, or pump failure results from the inability of the heart muscle to pump enough blood to supply the whole body.
The different determinants of cardiac output such as heart rate, stroke volume, preload, and afterload are affected in heart failure.

Inability to pump sufficient blood results in:
Decreased tissue perfusion as evidenced by fatigue, weakness, and activity intolerance
Pulmonary and systemic congestion or volume overload as evidenced by jugular venous distention, peripheral edema, and dyspnea.

Diuretics, ACE inhibitors, angiotensin II receptor blockers (ARBs), and beta adrenergic blockers are the medications of choice for treatment of heart failure. Cardiac glycosides are indicated if these medications are unable to control symptoms.
Cardiac Glycosides

Select Prototype Medication: digoxin (Lanoxin, Lanoxicaps, and Digitek)
Expected Pharmacological Action
Positive inotropic effect = increased force of myocardial contraction
Increased force and efficiency of myocardial contraction improves the heart s effectiveness as a pump, improving stroke volume and cardiac output.
Negative chronotropic effect = decreased heart rate
At therapeutic levels, digoxin slows the rate of SA node depolarization and the rate of impulses through the conduction system of the heart.
A decreased heart rate gives the ventricles more time to fill with blood coming from the atria, which leads to increased SV and increased CO.
Therapeutic Uses
Treatment of heart failure
Dysrhythmias (atrial fibrillation)

Contraindications/Precautions
Cardiac glycosides are Pregnancy Risk Category C.
These agents are contraindicated in clients with disturbances in ventricular rhythm, including ventricular fibrillation, ventricular tachycardia, and second- and third-degree heart block.
Use cautiously in clients who have hypokalemia, partial AV block, advanced heart failure, and renal insufficiency.
Interactions
Nursing Administration
Advise clients to take the medication as prescribed. If a dose is missed, the next dose should not be doubled.
Check pulse rate and rhythm before administration of digoxin and record. Notify the provider if heart rate is less than 60/min in an adult, less than 70/min in children, and less than 90/min in infants.
Administer digoxin at the same time daily.
Monitor digoxin levels periodically during treatment and maintain therapeutic levels between 0.5 to 2.0 ng/mL to prevent digoxin toxicity.
Avoid taking OTC medications to prevent adverse and side effects and medication interactions.
Instruct clients to observe symptoms of hypokalemia, such as muscle weakness, and to notify the provider if symptoms occur.
Instruct clients to observe symptoms of digoxin toxicity (anorexia, fatigue, weakness), and to notify the provider if symptoms occur.
Management of digoxin toxicity
Digoxin and potassium-sparing medication should be stopped immediately.
Monitor K+ levels. For levels less than 3.5 mEq/L, administer potassium intravenously or by mouth. Do not give any further K+ if the level is greater than 5.0 mEq/L.
Treat dysrhythmias with phenytoin (Dilantin) or lidocaine.
Treat bradycardia with atropine.
For excessive overdose, activated charcoal, cholestyramine, or Digibind can be used to bind digoxin and prevent absorption.
Nursing Evaluation of Medication Effectiveness
Depending on therapeutic intent, effectiveness may be evidenced by:
Control of heart failure signs and symptoms.
Absence of cardiac dysrhythmias.
Adrenergic Agonists
Select Prototype Medication:
Catecholamines:
Epinephrine (Adrenaline)
Dopamine (Intropin)
Dobutamine (Dobutrex)
Other Medications
Isoproterenol: catecholamine
Terbutaline: noncatecholamine
Purpose
Therapeutic Use


Side/Adverse Effects

Contraindications/Precautions
Epinephrine and dopamine are Pregnancy Risk Category C.
Dobutamine is Pregnancy Risk Category B.
These medications are contraindicated in clients who have tachydysrhythmias and ventricular fibrillation.
Use cautiously in clients who have hyperthyroidism, angina, history of myocardial infarction, hypertension, and diabetes.
Interactions
Nursing Administration
This medication must be administered IV by continuous infusion.
Use an IV pump to control infusion.
Dosage is titrated based on blood pressure response.
Stop the infusion at first evidence of infiltration. Extravasation can be treated with local injection of an alpha-adrenergic blocking agent, such as phentolamine.
Assess/monitor clients for chest pain. Notify the provider if chest pain occurs.
Provide continuous ECG monitoring. Notify the provider of signs of tachycardia or dysrhythmias.
Nursing Evaluation of Medication Effectiveness
Depending on therapeutic intent, effectiveness may be evidenced by:
Improved perfusion as evidenced by urine output of > 30 mL/hr (with normal renal function), improved mental status, and systolic blood pressure maintained at > 90 mm Hg.