What is heart failure?
The heart is a pump that pumps blood containing oxygen and nutrients to the rest of the body. Heart failure is a condition in which the heart is unable to pump enough blood to meet the needs of the other organs in the body. This is usually caused by the heart muscle becoming weak. The failing heart doesn’t stop but works less efficiently than before.
As the blood flow leaving the heart is slowed, this builds up a backpressure through the lungs and veins, causing congestion in the tissues. Most commonly this fluid accumulates in the lungs and the legs: the site of fluid accumulation depends upon which chambers of the heart have been affected. Fluid in the lungs interferes with breathing and fluid in the legs causes swelling known as oedema. Heart failure also affects the kidneys ability to get rid of salt and water. As a consequence the retained water makes the congestion and oedema worse.
The symptoms that patients experience from heart failure include:
- Shortness of breath on exertion or at rest
- Breathlessness or coughing when laid flat
- Waking up breathless at night
- Tiredness and fatigue
- Swelling of the ankles and feet
- Loss of appetite
- The stomach feeling swollen or bloated
- Sputum production (which can be bloodstained)
It is important to note that these symptoms are not always due to heart failure. We all get breathless on exertion and there are other medical conditions that may cause similar symptoms. It is only a problem if your symptoms change without reason or if you are much more breathless than other people of a similar age. However, do not accept the above symptoms are due to old age; consult your doctor if you are concerned.
What causes heart failure?
In order for the heart to work efficiently as a pump it requires the muscle, the valves and the electrical activity to work satisfactorily. Sometimes problems arise that prevent the heart pumping efficiently. As the muscle weakens, the heart enlarges and pumps less effectively. This results in a backpressure through the lungs, causing congestion in the lungs and the veins, which in turn causes swelling of the feet, ankles and legs.
The commonest cause of heart failure in the Western world arises from the muscle damage that is caused by heart attacks. In this situation the surviving heart muscle has been left unable to maintain an adequate pumping action.
Heart failure may also result from conditions that make the heart work harder, such as:
- High blood pressure, which increases the work the heart has to do.
- Leaking or narrowed heart valves, which impair the normal flow of blood through the heart.
- Slow or fast heart rhythms, which affect the filling and pumping action of the heart.
- Anaemia, which reduces the supply of oxygen to the heart muscle.
- Thyroid disease, which can increase the metabolism in the body, making the heart work harder than normal.
- Lung disease, which can result in low oxygen levels in the blood.
Occasionally too much alcohol, certain drugs or viral infections can damage the heart muscle. The term cardiomyopathy refers to chronic damage of the heart muscle. The cause of the heart muscle damage often remains unclear.
How is heart failure diagnosed?
A diagnosis of heart failure can often be made based on the characteristic symptoms of:
- Shortness of breath on exertion or at rest.
- Breathlessness or coughing when laid flat (known as orthopnea).
- Waking up breathless at night.
- Tiredness and fatigue.
- Swelling of the ankles and feet.
- Loss of appetite.
- The stomach feeling swollen or bloated.
- Sputum production (which may be bloodstained)
Examination by a doctor may detect an irregular heartbeat, abnormal blood pressure, an enlarged heart, or abnormal heart sounds when listening with a stethoscope. There may be signs of congestion in the lungs, the neck veins and the liver, or swelling in the legs.
It is usually difficult to make a definite diagnosis of heart failure without further tests. These may include:
- Blood tests to look for anaemia, thyroid disease or evidence of kidney damage.
- A chest X-ray to see if the heart is enlarged or if there is congestion in the lungs. The X-ray may show a different problem in the lungs that could be causing breathlessness other than that due to heart failure.
- A heart tracing called an electrocardiogram or ECG to look for any evidence of previous damage to the heart muscle such as that caused by heart attacks.
- An ultrasound scan of the heart called an echocardiogram. This is a painless test that provides important information about the way the heart is working. It provides pictures of the heart in motion and allows the doctor to assess the pumping action of the heart and how the heart valves are working.
How is heart failure treated?
Heart failure is a serious condition but starting treatment early offers the best chance for a longer and improved quality of life.
Treatment is aimed at controlling the symptoms and treating the underlying cause of the heart failure. This can include coronary heart disease, high blood pressure, valvular heart disease, heart rhythm disturbances, anaemia and thyroid or kidney disorders. As there are many different causes of heart failure, treatment will differ from one patient to another.
In the majority of patients the cause of their heart failure is damage to the heart muscle. Although there is no cure for this at present, the outlook for patients with heart failure has improved significantly in recent years as a result of advances in treatment.
Symptoms can be improved by:
Lifestyle modification such as:
- Diet (in particular salt and water restriction and weight loss)
- Regular exercise.
- Stopping smoking.
- rest and relaxation
- Diuretics (commonly known as ‘water tablets’) which help the body to lose salt and water through the kidneys and so reduce the heart’s workload.
- Angiotensin converting enzyme inhibitors, (known as ACE inhibitors) which act by dilating blood vessels in the body. By doing so they reduce the heart’s workload each time it pumps blood into the circulation. Unfortunately, not all patients are suitable for, or able to tolerate, ACE inhibitors.
- Digoxin can be useful in patients with an irregular heartbeat to control the speed of the heart.
- Beta-blockers slow the speed and the force of the heartbeat thus reducing the work the heart has to do. They were previously thought to be unsuitable for patients with heart failure but recent research shows they can be of great benefit. Their introduction requires careful supervision
Pacemakers; these may be needed in a small minority of patients whose heart failure is due to either a slow heartbeat or abnormal patterns of electrical conduction.
The symptoms of heart failure may not always be controlled with medication. If the heart failure is due to coronary heart or valvular heart disease then coronary artery bypass surgery or valve surgery may need to be considered. In a very small percentage of carefully selected patients consideration of heart transplantation may be necessary. Unfortunately this is not suitable for everyone and the number of transplants that can be performed is severely limited by the number of donors.