Heart Failure Overview Lesson

Jun 23, 2024

Heart Failure Overview Lesson

Introduction

  • Presenter: Eddie Watson
  • Series Topic: Heart Failure
  • Objectives: To understand the basics of heart failure, its pathophysiology, causes, and how it manifests in patients.

Importance of Heart Failure Knowledge

  • Prevalence: Over 5 million people in the US live with heart failure, with 550,000 new diagnoses annually.
  • Mortality: Approximately 287,000 deaths per year due to heart failure.
  • Common in Elderly: Most common diagnosis in patients over 65.
  • Gender and Race: Equal rates in men and women, but African Americans have a 1.5 times higher risk.

Heart Function

  • Primary Function: To pump blood throughout the body.
  • Circulatory Pathway:
    • Deoxygenated blood enters the right heart -> pumped to lungs -> oxygenated blood returns to left heart -> pumped to body.
  • Heart Failure: Occurs when the heart can't pump blood effectively.

Heart Failure Basics

  • Impaired Cardiac Function: Can affect the left side, right side, or both (biventricular failure).
  • Cardiac Output Equation: CO = Heart Rate (HR) x Stroke Volume (SV).
  • Issues in Heart Failure:
    • Decreased stroke volume -> inadequate cardiac output to meet body's demands.

Pathophysiology of Heart Failure

  • Two Primary Dysfunctions:
    1. Systolic Heart Failure (Contraction Issue):
      • Decreased strength of the heart muscle
      • Enlarged chambers, weakened heart walls
    2. Diastolic Heart Failure (Filling Issue):
      • Thickened heart muscles
      • Reduced chamber size -> less blood filling

Types of Heart Failure

  • Left-Sided Heart Failure: Often precedes right-sided failure.
  • Right-Sided Heart Failure: Can lead to biventricular failure.
  • Both Systolic and Diastolic Failures can occur on either side.

Causes of Heart Failure

  • Secondary Condition: Results from underlying diseases (e.g., lifestyle choices, chronic diseases).
  • Cycle of Worsening: Death of cardiac muscle -> decreased cardiac output -> compensation -> overworked heart -> more muscle death.

Compensation Mechanisms

  1. Sympathetic Nervous System Activation:
    • Increases heart rate and contraction force (beta receptors).
    • Long-term activation -> receptor downregulation -> decreased response.
  2. Increasing Preload:
    • More blood volume in ventricles before contraction.
    • Increased stretch -> more forceful contraction (Frank-Starling Law).
    • Hormonal Influence: ADH and Aldosterone -> fluid retention -> increased blood volume.
  3. Myocardial Hypertrophy:
    • Growth in size and number of heart muscle cells.
    • Increased muscle mass -> higher oxygen demand -> more cell death -> progression of heart failure.

Decompensation

  • Overuse of Compensation Mechanisms:
    • Worsens heart failure symptoms.
    • Leads to a state where compensation mechanisms fail to maintain adequate cardiac output.

Conclusion

  • Summary:
    • Heart failure basics, prevalence, heart function review, pathophysiology of systolic and diastolic failures, types of heart failure, compensatory mechanisms, and causes.
  • Next Lesson: Differences between systolic and diastolic heart failure and more detailed pathophysiology.
  • Additional Resources: Previous lesson on the Glasgow Coma Scale and references to related videos and notes.

Thank you for watching! If you found this lesson useful, please like and comment below. Stay tuned for the next lesson where we dive deeper into the differences in heart failure types.