9. Acute heart failure

From greek.doctor

In acute cardiac failure there is a sudden decrease in cardiac output. It mostly occurs due to:

  • Acute inefficient ventricular filling
    • Right heart: vena cava occlusion
    • Left heart: pulmonary embolism
  • Acute inefficient ventricular contraction
    • Asystole
    • 3rd degree AV-block
    • Ventricular fibrillation
    • Acute valvular rupture
    • Toxic or metabolic myocardial injury
    • Myocardial infarction
    • Aneurysm

Acute heart failure can occur as the first presentation of heart disease but it’s more common as a decompensation of pre-existing heart disease. In this case the condition is called acute decompensated heart failure.

The consequences can be deadly but depend on the severity of the cardiac dysfunction. In no particular order:

  • Severe cerebral hypoperfusion can lead to death within minutes
  • Pulmonary oedema and syncope
  • Rapid development of extreme fatigue and dyspnoea
  • Cardiogenic shock
  • Worsening of forward failure symptoms, mild cerebral hypoperfusion

The (figurative) connection between acute heart failure and pulmonary oedema goes through the brain. Acute heart failure causes cerebral hypoxia, which (by an unknown mechanism) causes capillary permeability in the lungs to increase which causes fluid to leak into the alveoli.

This explanation is the pathophysiology department’s explanation. Other sources state increased pulmonary capillary pressure as the reason pulmonary oedema develops.