EXERTIONAL DYSPNOEA

This is the most troublesome symptom in heart failure. Exercise causes a sharp increase in left atrial pressure and this contributes to the pathogenesis of dyspnoea by causing pulmonary congestion (see above). However, the severity of dyspnoea does not correlate closely with exertional left atrial pressure, and other factors must therefore be important. These include respiratory muscle fatigue and the effects of exertional acidosis on peripheral chemoreceptors. As left heart failure worsens, exercise tolerance deteriorates. In advanced disease the patient is dyspnoeic at rest.