Neuro-endocrine Responses in CHF

• Neuro-endocrine responses:

  • sympathetic nervous system activation
  • increase in heart rate/inotropy and total peripheral resistance -> increase in cardiac output and blood pressure
  • venoconstriction -> increase in venous return -> increase in cardiac output -> also increases blood pressure (BP = TPR x CO)
  • RAAS - renin-angiotensin-aldosterone system
  • release of angiotensin II - is a vasoconstrictor of arterioles -> increase in total peripheral resistance and blood pressure
  • release of aldosterone - boosts volume by aiding water retention -> increase in cardiac output and blood pressure
  • release of ADH - boosts volume by aiding water retention & increase in total peripheral resistance & is a vasoconstrictor -> increase in cardiac output and blood pressure
  • all the above increase cardiac output and blood volume, but is not suitable in the long term
• • the neuroendocrine response is not suitable in the long term
  • in the long term the neuroendocrine response:
  • causes increase in circulatory volume -> increase in pre-load
  • causes increase in venoconstriction -> increase in pre-load
  • increase in pre-load -> increase in ventricular workload & exacerbates congestion/symptoms
  • causes increase in total peripheral resistance -> increase in after-load -> increase in left ventricular workload
  • sustained increase in sympathetic nervous system activity -> decrease in cardiac sympathetic nervous system receptor sensitivity