Lecture Notes on Heart Failure

Definition and Overview

• Heart Failure: Condition where the heart cannot supply enough blood to meet the body's demands.
  • Systolic Heart Failure: 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 leading to congestion or fluid buildup.
• Affects millions globally and can lead to death.
• Caused by various heart diseases like ischemia and valvular disease.

Key Concepts

• Cardiac Output: Volume of blood the heart pumps per minute (Heart rate x Stroke volume).
  • Normal ejection fraction: 50-70%.
  • Systolic heart failure indicated if ejection fraction <40%.
• Diastolic Heart Failure: Low stroke volume, but normal ejection fraction due to low total volume.

Mechanisms

• Frank-Starling Mechanism: Increased blood during diastole stretches cardiac muscle, enhancing contraction force.

Types of Heart Failure

• Left-Sided Heart Failure: Typically due to systolic dysfunction.

  • Common cause: Ischemic heart disease (coronary artery atherosclerosis).
  • Hypertension and dilated cardiomyopathy also lead to systolic failure.
  • Can also result from diastolic dysfunction.

• Right-Sided Heart Failure: Often caused by left-sided failure.

  • Increases pulmonary pressure making it difficult for the right side to pump blood.
  • Can be isolated in cases like left-to-right cardiac shunts or chronic lung disease (cor pulmonale).

Symptoms and Effects

• Pulmonary Symptoms: Blood backing up in pulmonary veins, edema, dyspnea, orthopnea, crackles on auscultation, and 'heart failure cells'.
• Systemic Symptoms: Jugular venous distention, hepatosplenomegaly, ascites, and pitting edema.

Treatment

• Medications: ACE inhibitors and diuretics to improve blood flow and reduce fluid buildup.
• Advanced Treatments: Cardiac resynchronization therapy, ventricular assist devices (VADs), and heart transplants in end-stage.

Conclusion

• Heart failure can lead to heart arrhythmias.
• Right-sided failure often results from left-sided failure.
• Proper management includes medications and in severe cases, surgical interventions.