Paper II
Question
Left sided heart failure
Answer
Left-sided heart failure occurs when the left ventricle fails to pump blood effectively, causing back-pressure into the pulmonary circulation.
Common causes
- Ischaemic heart disease/myocardial infarction
- Systemic hypertension
- Mitral or aortic valve disease
- Primary myocardial disease (cardiomyopathy)
Morphological/clinical effects (predominantly pulmonary)
- Lungs: Pulmonary venous congestion and oedema — heavy, boggy lungs; alveolar septa congested; intra-alveolar transudate; haemosiderin-laden macrophages (“heart failure cells”) from microhaemorrhages
- Clinical features: Dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, fine crepitations on auscultation
Downstream/secondary effects
- Reduced forward cardiac output leads to reduced renal perfusion, activating the renin-angiotensin-aldosterone system, causing sodium/water retention, which worsens congestion
- Reduced cerebral perfusion can cause hypoxic encephalopathy, irritability, confusion in severe cases
- Prolonged left heart failure eventually leads to pulmonary hypertension and secondary right-sided heart failure (congestive cardiac failure)