Heart Failure Lecture Notes

Introduction to Heart Failure

• Clinical syndrome where the heart can't meet the body's perfusion demands.
• Two main types:
  • Systolic Heart Failure: Reduced ejection fraction, impaired pumping.
  • Diastolic Heart Failure: Preserved ejection fraction, impaired filling.

Key Definitions

• Cardiac Output (CO): Volume of blood pumped per minute (Stroke Volume x Heart Rate).
• Stroke Volume (SV): Blood volume per beat (~70 ml).
• Ejection Fraction (EF): SV divided by end-diastolic volume, normal is 55-70%.
• Systole: Ventricular contraction.
• Diastole: Ventricular relaxation/filling.

Types of Heart Failure

• Reduced Ejection Fraction: EF < 40%.
• Preserved Ejection Fraction: EF normal or high.
• Mildly Reduced Ejection Fraction: EF 40-49%.
• Left-sided, Right-sided, Biventricular: Based on the ventricle affected.
• Acute or Chronic: Based on symptom onset.

Causes

• Reduced EF:
  • Coronary Artery Disease, Myocardial Infarction.
  • Chronic volume overload (valvular diseases).
  • Neurohormonal compensation (renin-angiotensin-aldosterone system).
  • Dilated cardiomyopathy, Increased afterload (aortic stenosis, hypertension).
• Preserved EF:
  • Diastolic dysfunction, left ventricular hypertrophy.
  • Restrictive cardiomyopathy, myocardial fibrosis, pericardial constriction.

Risk Factors

• Common: Obesity, Hypertension, Diabetes, Renal Disease.
• Unique to Preserved EF: Seen more in elderly, more common in females.

Symptoms and Diagnosis

• Symptoms: Dyspnea, Orthopnea, Paroxysmal Nocturnal Dyspnea, Peripheral Edema.
• Signs: Raised jugular venous pressure, Abnormal heart sounds.
• Tests:
  • N-terminal PROBNP (diagnostic and prognostic marker).
  • Imaging: X-rays (pulmonary edema, cardiomegaly) and Echocardiography.

Treatment

• Management Goals: Reduce mortality, Manage symptoms.
• Pharmacological:
  • Reduced EF:
    • Angiotensin Receptor Neprilysin Inhibitors (Sacubitril-Valsartan).
    • SGL2 inhibitors (dapagliflozin, empagliflozin).
    • Beta-blockers, ACE inhibitors, Aldosterone antagonists.
  • Preserved EF: No therapies to improve prognosis, symptom control.
  • Diuretics (symptom relief, not mortality reduction).
  • Digoxin (may improve symptoms).
• Non-pharmacological:
  • Devices (Cardiac resynchronization therapy, Implantable defibrillators).
  • Revascularization, Valve repair/replacement.
• Lifestyle modifications and risk factor control are essential.

Prognosis and Functional Assessment

• Prognosis: 50% mortality in five years.
• Functional Status:
  • NYHA: Physical capability and risk stratification.
  • ACC/AHA: Disease stage information.