Heart Failure

Heart Failure

• Heart failure occurs when the heart is unable to function properly, which can be due to:
  • Obstruction.
  • General disorder.
  • Hypertension.
  • Damage to heart tissue.
• The heart is unable to pump enough blood to meet the body's needs (insufficient perfusion).
• The heart cannot fill adequately, leading to reduced blood supply to the body.
• Stagnant blood can back up into the lungs (especially in right-sided heart failure).

Right-Sided Heart Failure

• The right ventricle is unable to pump effectively to the lungs.
• Fluid backs up from the right side of the heart.
• Jugular vein distention (JVD) is more commonly observed in right-sided heart failure, although it can occur in both left and right-sided failure.
• Mixed heart failure involves both left and right sides.

Left-Sided Heart Failure

• Fluid backing up causes dilation of structures before the lungs fill up.
• Imbalance in the pumping between the right and left sides of the heart.

Types of Systolic Heart Failure

• Heart failure with reduced ejection fraction (HFrEF).
• The heart's ability to pump is compromised, leading to fluid accumulation.
• Analogy: a rubber band that loses its elasticity and cannot effectively expel fluid.

Types of Diastolic Heart Failure

• Heart failure with preserved ejection fraction (HFpEF).
• Heart is stiff during rest, reducing filling capacity, ultimately reducing blood supply.
• If untreated with medication or interventions, diastolic heart failure can progress to systolic heart failure.
• Both systolic and diastolic heart failure can lead to left-sided heart failure and potentially shock.
• In diastolic heart failure, the ejection fraction might be preserved because the initial volume is small.
• With a small initial volume, ejecting 60% may still be sufficient for the ejection fraction, but still not enough.

Ejection Fraction (EF)

• $EF$ is the percentage of blood ejected from the heart with each contraction.
• $EF = \frac{Volume Ejected}{Total Volume}$
• In diastolic heart failure, the EF can be normal, but the total amount of blood being pumped is insufficient.
• Cardiac output is compromised in both systolic and diastolic heart failure.

Compensatory Mechanisms

• The body tries to compensate for reduced cardiac output by:
  • Increasing heart rate.
  • Vasoconstriction.
• These mechanisms increase the heart's workload and can worsen heart failure.

Systolic vs. Diastolic Heart Failure Location

• Systolic and diastolic failure can occur on both sides of the heart, but are more commonly observed on the left side.

RAS (Renin-Angiotensin System)

• The RAS system increases blood pressure through vasoconstriction.
• The RAS signals the kidneys to retain fluid.
• Brain Natriuretic Peptide (BNP)
  • BNP is released when the heart is under stress.
  • BNP levels higher than 500 indicate heart failure.
  • BNP tells the kidneys to get rid of fluid.

Cardiac Shock

• Acute, sudden onset of symptoms that can occur with or without pre-existing chronic heart failure.
• Causes can include:
  • Myocardial infarction (MI).
  • Trauma.
  • Drug addiction.
  • Infection (e.g., endocarditis).
  • Motor vehicle crashes.

Cardiogenic Shock

• A multi-organ failure due to insufficient oxygen perfusion.
• Tissues and organs are unable to function properly.
• Can result from diastolic dysfunction.
• Treatment involves a balance of diuresis to remove fluid and maintain adequate fluid levels.
• Hemodynamics guide fluid management.
• Medical interventions often counteract the body's compensatory mechanisms.
• Assessment findings:
  • Oxygen requirements.
  • Edema in ankles.
  • Daily weights.

Anaerobic Metabolism

• Inadequate perfusion leads to anaerobic metabolism.
• Anaerobic metabolism generates lactic acid.
• Detected as lactic acid in arterial blood samples.

Other Clinical Manifestations

• Nocturia: increased urination at night due to improved kidney perfusion when lying down.
• Clubbing of nails: indicates heart signaling overload.
• Chest X-ray: reveals an enlarged heart.
• Liver function tests (LFTs): assess liver function, which can be impaired due to fluid overload.
  • The liver produces proteins essential for blood volume and osmosis.

Medications and Interventions

• Morphine can be used to offload the heart by reducing preload and afterload.
• Beta blockers slow heart rate and improve filling; caution with decompensated patients.
• Sodium nitroprusside: potent vasodilator used in hypertensive emergencies.
• Ventricular assist devices (VADs) act as a bridge to transplant or destination therapy.

Nursing Considerations

• Careful monitoring of fluid balance is crucial.
• Assessments include:
  • Labs.
  • Vital signs.
  • Level of consciousness.
  • Diagnosis.
• Common nursing diagnoses:
  • Impaired gas exchange.
  • Decreased cardiac output.
  • Activity intolerance.