9.7 Cardiac Conditions (Heart Failure)

Cardiac Conditions: Heart Failure

Heart failure (HF) is a clinical syndrome in which the heart cannot pump enough blood to meet the body's metabolic demands. It is a chronic, progressive condition that is a leading cause of hospitalization and mortality.

Pathophysiology

Heart failure occurs when:

• The heart's pumping ability (contractility) is impaired
• The heart cannot fill properly (diastolic dysfunction)
• Or both

Compensatory Mechanisms (Initially helpful, eventually harmful):

1. Sympathetic activation - Increases heart rate and contractility
2. Renin-angiotensin-aldosterone system (RAAS) - Retains sodium and water
3. Cardiac remodeling - Heart enlarges (ventricular hypertrophy)

These compensations initially maintain cardiac output but eventually worsen heart failure.

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Types of Heart Failure

Left-Sided Heart Failure (Most Common)

The left ventricle cannot pump blood effectively to the systemic circulation. Blood backs up into the pulmonary system.

Causes:

• Hypertension (most common)
• Coronary artery disease
• Myocardial infarction
• Cardiomyopathy
• Valvular disease (aortic stenosis, mitral regurgitation)

Clinical Manifestations:

Memory Aid: "Left = Lungs" - Left-sided failure causes LUNG symptoms

Right-Sided Heart Failure

The right ventricle cannot pump blood effectively to the lungs. Blood backs up into the systemic venous circulation.

Causes:

• Usually secondary to left-sided heart failure
• Pulmonary hypertension
• COPD (cor pulmonale)
• Pulmonary embolism
• Right ventricular infarction

Clinical Manifestations:

Memory Aid: "Right = Rest of body" - Right-sided failure causes SYSTEMIC symptoms

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Heart Failure Classification

New York Heart Association (NYHA) Classes

Ejection Fraction Categories

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Diagnostic Tests

BNP (B-type Natriuretic Peptide):

• Released when ventricles are stretched
• BNP > 100 pg/mL suggests heart failure
• Higher levels indicate more severe HF

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Treatment of Heart Failure

Pharmacological Management

Diuretics (Reduce Volume Overload):

• Loop diuretics: Furosemide (Lasix), bumetanide
  • Most effective for fluid removal
  • Monitor for hypokalemia
• Thiazides: Hydrochlorothiazide
  • Mild HF or adjunct therapy
• Potassium-sparing: Spironolactone
  • Also blocks aldosterone (mortality benefit)

ACE Inhibitors (First-line, Reduce Afterload):

• Examples: Lisinopril, enalapril, captopril
• Block RAAS, reduce preload and afterload
• Monitor for hyperkalemia, cough, angioedema
• Hold if SBP < 90 mmHg

ARBs (Alternative if ACE-I intolerant):

• Examples: Losartan, valsartan
• Similar benefits without cough

Beta-Blockers (Reduce Workload):

• Examples: Carvedilol, metoprolol succinate, bisoprolol
• Reduce heart rate and oxygen demand
• Start low, go slow (may initially worsen symptoms)
• Mortality benefit in chronic HF

Digoxin (Improve Contractility):

• Positive inotrope
• Narrow therapeutic index (0.5-2.0 ng/mL)
• Check apical pulse; hold if < 60 bpm
• Monitor for toxicity: nausea, yellow/green halos, arrhythmias

SGLT2 Inhibitors (Newer agents):

• Examples: Empagliflozin, dapagliflozin
• Reduce hospitalizations and mortality
• Originally diabetes drugs, now standard HF therapy

Non-Pharmacological Management

Sodium Restriction:

• < 2 g (2000 mg) per day
• Avoid processed foods, canned goods, restaurant food

Fluid Restriction:

• Typically 1.5-2 L/day in severe HF
• Helps prevent volume overload

Daily Weights:

• Weigh at same time, same scale, same clothing
• Report weight gain of 2-3 lbs in one day or 5 lbs in one week
• 1 kg = 1 L of fluid

Activity:

• Balance rest and activity
• Cardiac rehabilitation when stable
• Avoid strenuous exercise during exacerbations

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Nursing Interventions

Monitoring:

• Daily weights (most accurate fluid status indicator)
• Strict I&O
• Vital signs, especially BP before ACE-I/beta-blockers
• Lung sounds every 4-8 hours
• Edema assessment
• Oxygen saturation

Positioning:

• Semi-Fowler's or high Fowler's (reduces venous return, eases breathing)
• Elevate legs if tolerated (but may worsen pulmonary congestion in severe cases)

Oxygenation:

• Administer oxygen as ordered
• Monitor for respiratory distress
• Prepare for CPAP/BiPAP if needed

Patient Education:

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Acute Decompensated Heart Failure

When chronic HF suddenly worsens, requiring urgent intervention.

Triggers:

• Medication non-adherence
• Dietary indiscretion (high sodium)
• Infection
• Arrhythmia
• Myocardial ischemia

Treatment:

• IV diuretics (furosemide)
• Vasodilators (nitroglycerin, nitroprusside)
• Oxygen, BiPAP
• Inotropes (dobutamine, milrinone) for cardiogenic shock
• Morphine (use with caution)

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Key Points for the NCLEX

• Left-sided HF = Lung symptoms (crackles, dyspnea, orthopnea)
• Right-sided HF = Systemic symptoms (edema, JVD, hepatomegaly)
• Daily weights are the BEST indicator of fluid status
• Weight gain of 2-3 lbs in one day = report immediately
• ACE inhibitors and beta-blockers improve mortality
• Hold digoxin if apical pulse < 60 bpm
• Position in high Fowler's to reduce respiratory distress
• Sodium restriction < 2 g/day is essential