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Heart Failure (Definition (Is a syndrome, rather than a specific diagnosis…

- - - - Examples: bisoprolol
      - Do not give to asthmatics!
      - Start low dose and titrate upwards slowly
      - The best drug to give to patients with reduced ejection fraction
    - - Examples: ramipril
      - If cough is a problem, give angiotensin receptor blocker
      - Improves symptoms and prolongs life
    - - Decreases pulmonary congestion and oedema
      - Provide symptomatic relief
      - Promote sodium and therefore water loss
      - Thiazide diuretic: bendroflumethiazide
      - Loop diuretic: furosemide
      - Aldosterone antagonist (inhibits ADH release): spirolactone
    - - These are arterial and venous dilators
- - - - Angiotensin II stimulates the release of aldosterone from the adrenal cortex
      - Aldosterone increases sodium reabsorption and thus water reabsorption. Also releases ADH to retain water
      - Angiotensinogen is converted to angiotensin I by renin. Angiotensin I is converted to angiotensin II by ACE
      - All this results in an increased volume of blood, increasing BP, venous pressure and therefore pre-load and cardiac output
      - Reduced cardiac output lowers renal perfusion, activating the renin-angiotensin system
      - The cardiac myocytes need more blood to maintain the increased force of contraction
      - In heart failure, there is no increased blood flow so the cardiac myocytes die causing a decreased force of contraction and cardiac ouput
    - - The force of contraction is increased, increasing stroke volume and heart rate, thus increasing cardiac ouput
      - In heart failure, there is chronic sympathetic activation
      - Baroreceptors stimulate sympathetic activation in response
      - There are fewer receptors to act on, so sympathetic activation is diminished and cardiac output stops increasing
      - Baroreceptors in the aorta, carotid and heart walls detect a drop in arterial pressure or an increase in venous pressure
  - - - Decreased stroke volume and cardiac output
      - Ejection fraction >50%
      - Inability of ventricles to relax and fill fully
      - Caused by ventricular hypertrophy, pericarditis, tamponade, hypertension
    - - Pulmonary or peripheral oedema
      - New onset or decompensation of chronic heart failure
      - Emergency
    - - Decreased cardiac output
      - Ejection fraction <40%
      - Inability of ventricle to contract normally
      - Caused by IHD, MI, cardiomyopathy
    - - Develops slowly
      - Venous congestion is common