heart failure

• Definition of Heart Failure:

  • Pathophysiological: inadequate pump function of the heart leads to inadequate perfusion of tissues despite normal or increased blood return
  • Clinical: inadequate pump function of the heart leads to congestion in some tissues and organs (congestive heart failure)
• Old concept of heart failure: Cardiac dropsy due to decompensation of ventricular hypertrophy

  Recent concept: Involves neuroendocrine, hormonal, and inflammatory factors, molecular mechanisms of adaptation and deadaptation
• Etiology of Heart Failure:

  • Damage of myocytes from myocardial infarction, cardiomyopathies, myocarditis, toxic damage
  • Chronic haemodynamic overload from volume overload (mitral, aortic regurgitation) and pressure overload (systemic hypertension, aortic stenosis)
• Etiology of Heart Failure (continued):

  • Arrhythmias like extreme tachycardia, supraventricular tachycardia, atrial fibrillation, extreme bradycardia
  • Restricted filling from conditions like mitral stenosis, constrictive pericarditis, pericardial tamponade, fibrosis
• Heart failure basic terms:

  • Forms: left ventricle vs right ventricle vs both ventricles, acute vs chronic, reduced vs preserved ejection fraction
  • Systolic vs diastolic dysfunction, forward vs backward failure, NYHA classification I – IV, compensated vs uncompensated
• Forward vs. backward failure:

  • Forward failure: inability of the heart to pump blood forward, leading to hypoperfusion
  • Backward (congestive) failure: blood dams back behind the failing heart, leading to specific symptoms and signs
• Left ventricular failure symptoms and signs:

  • Backward failure: pulmonary edema
  • Forward failure: muscle hypoxia, decreased sympathetic tone, heart ischemia, GIT and CNS hypoxia, increased concentration of reduced hemoglobin
• Right ventricular failure symptoms and signs:

  • Backward failure: peripheral edema, anasarca, ascites, hepato- and splenomegaly, hepatojugular reflux, jaundice, coagulopathy, nocturia
  • Forward failure: pulmonary hypoperfusion, shortness of breath
• Classification according to ejection fraction:

  • Normal ejection fraction: 50-75%
  • Heart failure with reduced ejection fraction (HFrEF), preserved EF (HFpEF), mid-range EF (HFmrEF)
• High-Output Cardiac Failure:

  • Less common form with normal cardiac function and decreased systemic vascular resistance
  • Etiology includes increased demand for blood, increased flow into venous circulation, and other factors like obesity, carcinoid syndrome
• Pressure vs. volume overload:

  • Pressure overload: ventricle develops increased effort during systole, causes include left and right ventricular pressure overload
  • Volume overload: excessive volume of blood in ventricle during diastole, causes include left and right ventricular volume overload
• Concentric vs. eccentric hypertrophy:

  • Concentric hypertrophy: increase in cardiac mass due to increased wall thickness
  • Eccentric hypertrophy: increase in chamber size without significant change in wall thickness
• The Stages of Heart Failure – NYHA Classification:

  • Class I (Mild) to Class IV (Severe) based on patient symptoms and limitations in physical activity
• Compensatory mechanisms:

  • Acute mechanisms like Frank-Starling mechanisms and catecholamines
  • Neurohumoral compensatory mechanisms involving catecholamines, RAAS, and ADH
  • Chronic compensatory mechanisms leading to hypertrophy