Chapter 37
Cardiac Glycosides, Antianginals, and
Antidysrhythmics
1
Heart Failure

Heart failure

Acute heart failure
• Heart muscle weakens and enlarges.
• Loses ability to pump blood adequately
• Compensatory mechanisms fail.
• Lungs and periphery become congested.
 Pathophysiology
• Preload
• Afterload
 Right-sided
• Blood backs up in periphery
 Left-sided
• Blood backs up in lungs
2
ACC/AHA Stages of Heart Failure
Stages
Characteristics
1 (A)
High risk for HF without symptoms or
structural disease
2 (B)
Some levels of cardiac changes (e.g.,
decrease ejection fraction without symptoms of
heart failure)
3 (C)
Structural heart disease with symptoms of HF
(e.g., fatigue, SOB, edema, decreased
physical activity)
4 (D)
Severe structural heart disease and marked
symptoms of HF at rest
3
Heart Failure

Nonpharmacologic treatment




Limit salt and saturated fat intake.
Limit or avoid alcohol intake; stop smoking.
Perform mild exercise.
Laboratory tests


Atrial natriuretic peptide (ANP)
• 20 to 77 pg/mL; 20 to 77 ng/L (SI units)
Brain natriuretic peptide (BNP)
• Desired value: less than 100 pg/mL
• Positive value: greater than 100 pg/mL
4
Cardiac Glycosides

Digitalis preparations (digoxin)

Action
• Positive inotropic

Increases myocardial contractility

Decreases heart rate

Decreases conduction

Increases cardiac output
• Negative chronotropic
• Negative dromotropic
• Increase stroke volume
5
Cardiac Glycosides (Cont.)

Digoxin


Side effects
• Bradycardia, cardiac dysrhythmias
• Anorexia, nausea, vomiting, diarrhea
• Headache, blurred or yellow vision
• Dizziness, weakness
Digitalis

Common signs of toxicity
• Anorexia, vomiting, diarrhea
• Blurred vision, green or yellow halos
• Bradycardia, premature ventricular contractions, cardiac
dysrhythmias
6
Cardiac Glycosides (Cont.)

Digitalis toxicity

Antidote
• Digoxin-specific antibody antigen-binding fragments (DSFab),
brand name Digibind or Digifab = effective antidote that directly
binds digoxin. indicated for life-threatening toxicity including:
Ventriculararrhythmias.

Drug interactions

Diuretics
• Hypokalemia
 Cortisone
• Sodium retention
 Antacids
• Decrease digitalis absorption

Contraindications: V. dysrhythmias, 2nd, 3rd AV block
7
Nursing Process: Digoxin

Assessment



Nursing diagnoses



Obtain a baseline pulse rate for future
comparisons.
Assess for evidence of digitalis toxicity.
Cardiac output, decreased related to
decreased cardiac pumping ability
Tissue perfusion, ineffective peripheral
related to decreased cardiac pumping ability
Planning

The patient will check pulse rate daily before
taking digoxin.
8
Nursing Process: Digoxin (Cont.)

Nursing interventions

Ascertain apical pulse rate before
administering digoxin.
 Determine signs of peripheral and
pulmonary edema.
 Monitor serum digoxin level.
 Monitor serum potassium level and report if
hypokalemia.
 Instruct patient to report side effects.

Evaluation
9
Phosphodiesterase Inhibitors

Milrinone lactate

Action: HF Tx
• Inhibit enzyme phosphodiesterase
• Promote positive inotropic effects
• Increase stroke volume and cardiac output
• Increase stroke volume and cardiac output and
promote vasodilation.

Caution
• Administer IV no longer than 48 to 72 hours to
avoid severe cardiac dysrhythmias.
• High alert medication
10
Other Agents Used to Treat
Heart Failure

Agents used to treat heart failure

Vasodilators
 Angiotensin-converting enzyme (ACE)
inhibitors
 Angiotensin II receptor antagonists (ARBs)
 Diuretics
• Thiazides, furosemide, spironolactone
 Some beta blockers
 Nesiritide: Inhibits ADH
 BiDil: Comb. Hydralazine & Isosorbide dinitrate
11
Angina

Classic (stable)


Unstable (preinfarction)


Occurs with predictable stress or exertion
Occurs frequently with progressive severity
unrelated to activity; unpredictable regarding
stress/exertion and intensity
Variant (Prinzmetal, vasospastic)

Occurs during rest
12
Types of Antianginal Drugs

Nitrates

Action
• Promote vasodilation
• Decrease preload and afterload
 Side effects and adverse reactions
• Headache, hypotension, flushing
• Dizziness, weakness, syncope
 Routes of administration
• Sublingual, topical, aerosol spray (inhalation), IV
• Buccal and oral extended-release capsule and tablet
 Caution
• Do not abruptly discontinue.
13
Beta Blockers

Beta blockers

Action
• Block beta1 and beta2 receptor sites
• Block the action of the catecholamines

Epinephrine and norepinephrine
• Decrease workload of heart and oxygen demands
 Side effects
• Bradycardia, hypotension, dizziness
• Depression, fatigue, sexual dysfunction
• Peripheral edema, bronchospasms
 Caution
• Do not abruptly discontinue.
14
Types of Antianginal Drugs

Calcium channel blockers


Action
• Relax coronary artery spasm
• Cause negative inotropic effect
• Reduce cardiac workload and oxygen demands
Side effects
• Dizziness, flushing, headache
• Hypotension, reflex tachycardia
• Peripheral edema, fatigue
15
Antianginal Drugs
Types of anginal pectoris with treatment
16
Nursing Process: Antianginal
Drugs

Assessment


Nursing diagnoses



Obtain baseline vital signs for future
comparisons.
Cardiac output, decreased related to poor
myocardial perfusion
Pain, acute related to angina pain due to
inadequate coronary perfusion and lack of
oxygen
Planning

The patient’s anginal pain will be decreased.
17
Nursing Process: Antianginal
Drugs (Cont.)

Nursing interventions


Monitor vital signs.
Position the patient sitting or lying down
when administering a nitrate for the first time.
 Monitor effects of IV nitroglycerin.
 Administer SL nitroglycerin tablet if chest pain
occurs.
 Advise patient not to ingest alcohol while
taking nitroglycerin.
 Instruct patient how to check their pulse.

Evaluation
18
Antidysrhythmic Drugs


Dysrhythmia
Cardiac action potentials

Phase 0 to phase 4
19
Antidysrhythmic Drugs (Cont.)


Mechanism of drug action
Class I

Sodium channel blockers
• 1A: slow conduction, prolongs repolarization
• 1B: slow conduction, shortens repolarization
• 1C: prolonged conduction with little/no effect on
repolarization

Class II

Beta-adrenergic blockers
• Reduce calcium entry
• Decrease conduction velocity, automaticity, and
recovery time
20
Antidysrhythmic Drugs (Cont.)


Mechanism of drug action
Class III

Prolong repolarization
 Prolong action potential duration

Class IV

Calcium channel blockers
• Block calcium influx
• Slow conduction velocity
• Decrease myocardial contractility
• Increase refraction in atrioventricular node
21
Nursing Process: Antidysrhythmics

Assessment


Nursing diagnoses



Obtain baseline vital signs and ECG for future
comparison.
Cardiac output, decreased related to cardiac
dysrhythmia
Anxiety related to irregular heartbeat
Planning

The patient will no longer experience abnormal
heart rhythm.
22
Nursing Process:
Antidysrhythmics (Cont.)

Nursing interventions





Monitor vital signs.
Monitor ECG for abnormal patterns and report
findings.
Tell patient to report side effects and adverse
reactions to a health care provider.
Advise patient to avoid alcohol, caffeine, and
tobacco.
Evaluation
23