Heart failure

What is heart failure

Heart failure happens when the heart is not able to pump enough blood around the body, and so too much fluid builds up in the lungs or body tissues. It can also happen when the ventricles (chambers in the heart) fail to pump enough blood to meet the body’s needs.

What causes heart failure

Heart failure can happen if the coronary arteries (arteries that supply blood to the heart) become blocked. When the heart doesn’t receive enough blood, the heart muscle gets damaged and a part of the heart muscle can die. It’s this damage to the heart muscle that can affect the heart’s ability to pump blood around the body. When heart failure happens, not enough blood is able to flow to organs and tissues.

Heart failure can also be caused by:

  • high blood pressure
  • chronic arrhythmias (i.e. atrial fibrillation), where the heart doesn’t beat in a regular rhythm
  • a glitch in the heart’s valves
  • drinking extreme amounts of alcohol
  • infection
  • cardiomyopathy (heart enlargement) of unknown cause.

Heart failure may happen very quickly – for example, when a person has a major heart attack – or over time and become a chronic (long-term) condition.

Signs and symptoms

If the heart muscle fails to pump enough blood around the body, fluid will start to build up. Fluid build up may lead to:

  • oedema – where fluid collects (fluid retention) in the spaces and tissues of the body
  • problems with breathing (especially when lying down), due to build up of fluid in the lungs – this is known as pulmonary oedema
  • increased tiredness and decreased exercise tolerance, due to the heart’s inability to beat faster to meet the increased demand for blood supply
  • increase in weight and swelling of the hands, legs or feet due to oedema
  • low blood pressure due to failure of the cardiovascular system
  • liver enlargement, jaundice and blood-clotting problems, because of fluid build up in the spaces of the abdominal area.


A number of prescription medicines are used to treat heart failure. They include:

  • angiotensin converting enzyme (ACE) inhibitors – decrease the workload of the heart by lowering blood pressure and preventing fluid retention in the kidneys
  • diuretics – increase urine output to help to stop fluid retention and oedema
  • vasodilators – open up blood vessels to help increase blood flow, which decreases the workload on the heart
  • beta blockers – slow down the heart rate and this decreases the workload on the heart
  • antiarrhythmic drugs – keep the heart in a normal heart rhythm
  • inotropic drugs – help to strengthen the heart beat as it pumps out blood.

What happens in the intensive care or coronary care units?

People with mild to moderate symptoms will generally be cared for by the cardiac team in a coronary care unit (CCU), or a combined intensive care and coronary care unit. People with serious symptoms may need to be admitted to the intensive care unit (ICU).

Usually, when the heart failure is extremely serious, the person may need a mechanical device to increase the amount of blood the heart pumps out. A heart transplant may be recommended for people with really serious disease.

People admitted to the ICU or CCU will be connected to a monitor so that their heart rate, blood pressure and other vital signs can be continually monitored. See Equipment.

During a serious episode, a ventilation device called continuous positive airway pressure (CPAP) can be used to deliver oxygen. This is a type of non-invasive ventilation, where the person breathes through a mask attached to the CPAP machine. A person may need full breathing support using an endotracheal tube (breathing tube) and ventilator (the breathing machine). See also Breathing support.

CPAP and full breathing support aims to reduce the work of breathing and help with shortness of breath.

Useful links

Publication details

Version 1.3. First published 2016. Next review 2023.


The information on this page is general in nature and cannot reflect individual patient variation. It reflects Australian intensive care practice, which may differ from that in other countries. It is intended as a supplement to the more specific information provided by the doctors and nurses caring for your loved one. ICNSW attests to the accuracy of the information contained here but takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.