Heart Failure Lecture Notes

Overview

• Heart failure: Condition where the heart cannot supply enough blood to meet the body’s demands.
  • Systolic heart failure: Heart's ventricles can't pump blood hard enough during systole.
  • Diastolic heart failure: Not enough blood fills the ventricles during diastole.
  • Congestive heart failure (CHF): Blood backs up into the lungs, causing congestion or fluid buildup.
  • Prevalence: Affects millions globally and can lead to death.

Causes

• Heart diseases: Ischemia, valvular disease, hypertension, cardiomyopathies.
• Left-sided heart failure:
  • Systolic dysfunction: Damage to myocardium (e.g., ischemic heart disease, longstanding hypertension, dilated cardiomyopathy).
  • Diastolic dysfunction: Concentric hypertrophy, restrictive cardiomyopathies.
• Right-sided heart failure: Often caused by left-sided heart failure.
  • Isolated right-sided failure: Left-to-right cardiac shunt, chronic lung diseases (cor pulmonale).

Systolic Heart Failure

• Cardiac output (CO): Heart rate (HR) x Stroke volume (SV).
• Ejection fraction (EF): SV/Total volume.
  • Normal: 50-70%
  • Borderline: 40-50%
  • Systolic heart failure: ≤40%

Diastolic Heart Failure

• Issue: Heart squeezes hard enough but does not fill adequately.
• Preload: Volume of blood in the ventricle before contraction.
• Frank-Starling mechanism: More blood during diastole increases contraction force during systole.

Clinical Signs & Consequences

• Left-sided heart failure:
  • Pulmonary edema: Fluid in alveoli, causing dyspnea, orthopnea, and crackles/rales.
  • Hemosiderin-laden macrophages: “Heart failure cells” due to blood leakage in alveoli.
  • Medications: ACE inhibitors, diuretics.
• Right-sided heart failure:
  • Jugular venous distention: Enlarged jugular vein.
  • Hepatosplenomegaly: Enlarged liver and spleen.
  • Ascites: Fluid buildup in peritoneal space.
  • Pitting edema: Swollen legs, sacrum (lower back when lying down).
  • Medications: Similar to left-sided heart failure (ACE inhibitors, diuretics).

Complications

• Arrhythmias: Irritated heart cells lead to uncoordinated contractions.
• Treatments:
  • Cardiac resynchronization therapy: Pacemakers for synchronized ventricular contractions.
  • Ventricular assist devices (VADs): Assist heart pumping.
  • Heart transplant: End-stage treatment.

Key Points

• Heart failure can be systolic or diastolic.
• Both left and right ventricles can be affected.
• Fluid buildup and congestion are primary issues.
• Medications and devices are used to manage symptoms and improve heart function.