As the contractility of the heart muscle is significantly reduced in left heart failure, the left ventricle does not pump enough after an increased cardiac load, cardiac output decreases and pulmonary venous and capillary pressures rise, resulting in fluid leakage and therefore pulmonary oedema.
Therefore, when a patient with heart failure develops symptoms such as marked dyspnoea, severe cough, pale or cyanotic skin, haemoptysis or pink frothy sputum, it is important to seek medical attention as soon as possible to clarify the cause and alleviate the symptoms.