Pharmacology of Heart Failure

• What is the NYHA Functional Classification of HF?

  I - no limitation of physical activity. Ordinary physical activity does not cause fatigue, palpitation, dyspnoea

  II - slight limitation of physical activity. Comfortable at rest, ordinary activity -> fatigue, palpitation or dyspnoea

  III - Marked limitation of physical activity. Less than ordinary activity causes fatigue, palpitation or dyspnoea

  IV - Unable to carry on any physical activity without discomfort. Symptoms of HF at rest
• What are the symptoms of left HF?

  Dyspnoea

  Orthopnoea

  Paroxysmal nocturnal dyspnoea

  Pulmonary congestion & oedema (crackles)

  Exercise intolerance
• What are the symptoms of right HF?

  Oedema of legs, ankles, feet

  Hepatomegaly - enlarged, palpable, tender liver

  Ascites

  Excessive nocturnal urination

  Increased JVP

  Exercise intolerance
• It is common for left & right sided HF to co-exist = biventricular failure
• What is the 'Vicious Cycle' of HF?

  Injury -> pump failure -> decreased CO -> decreased renal perfusion -> increase renin -> increased Na+ & fluid retention & vasoconstriction

  Increased venous congestion -> increased blood volume -> increased ANP/BNP/CNP

  = Increased afterload & preload -> increased cardiac work -> increased energy consumption -> cardiac remodelling -> worsens pump failure
• What diuretics are used for congestive heart failure (CHF)?

  Carbonic anhydrase inhibitors (not used anymore)

  Thiazides

  Loop diuretics

  K+ sparing diuretics (rarely used alone)