Heart failure does not mean that your heart is going to stop at any minute. It means that your heart is not functioning as well as it should. It can be caused by many different conditions.
How does the heart work?
The heart has four chambers – two atria and two ventricles. The walls of the heart chambers are made mainly of special heart muscle. Each heartbeat starts with a tiny electrical impulse near the top of the heart which spreads through the heart muscle, and makes it contract (squeeze).
The electrical impulse travels first through the walls of the atria, which contract to pump blood into the ventricles. The impulse then travels through to walls of the ventricles, which contract to pump blood into the arteries.
In a normal healthy heart, during each heartbeat a set amount of blood enters the heart and is pumped out again. If one has heart failure, the heart cannot cope with pumping the full amount of blood in each heartbeat.
Heart failure is usually classified on which heart function or which side of the heart is most affected, rather than the actual cause of heart failure. The main types are:
• Systolic heart failure. This means that the ventricles of the heart do not contract properly during each heartbeat so blood is not adequately pumped out of the heart. In some cases there is only a slight reduction in the power of the ventricle, which causes mild symptoms. If the power of the pumping action is more reduced then symptoms become more severe.
• Diastolic heart failure. This occurs when the ventricle does not fill up with blood enough when the heart rests in between each heartbeat. This can sometimes be due to the wall of the ventricle being stiffer than usual. This makes it more difficult to stretch.
• A combination of the above two types.
Heart failure may affect only the right ventricle (right-sided heart failure) or the left ventricle (left-sided heart failure), or both.
How common is heart failure?
Heart failure becomes more common as people get older. About 1 in 15 of people aged 75-84 and just over 1 in 7 people aged 85 and above have heart failure. It is uncommon in younger people.
What causes heart failure?
Heart failure is not an exact term. It may develop as a complication of various conditions. Conditions that cause heart failure affect the ability of the heart to function well as a pump. Conditions that may cause heart failure include the following:
Ischaemic heart disease (IHD)
IHD (also called coronary heart disease) is the most common cause of heart failure. In this condition, the blood flow to the heart muscle is reduced by narrowing of the coronary arteries that supply the heart muscle with blood and oxygen. The heart muscle may then not function as well as normal. Other symptoms of IHD may occur such as angina (See page xx).
In particular, heart failure may develop after a heart attack (see page xx). A heart attack is a complication of IHD and causes part of the heart muscle to die. Scar tissue forms in the affected part of the heart muscle. The larger the heart attack (and area of scar tissue), the more the function of the heart is affected.
Various other conditions can also cause heart failure. For example:
• Diseases of the heart muscle (cardiomyopathy).
• High blood pressure.
• Diseases of the heart valves.
• Diseases of the pericardium – the tissue that surrounds the heart.
• Some types of abnormal heart rhythms (arrhythmias).
• Drugs or chemicals that may damage the heart muscle – for example, alcohol excess, cocaine and some types of chemotherapy.
• Various non-heart conditions that can affect the function of the heart – for example, severe severe anaemia, thyroid disease and Paget’s disease.
Sometimes the cause of heart failure is not known.
What are the symptoms of heart failure?
The symptoms that may develop depend upon the type of heart failure that you have.
Generally, left heart failure causes breathlessness. This is generally worse on exertion (for example, walking up hill) or when lying flat in bed. This shortness of breath can be associated with a cough.
The main symptom of right heart failure is swollen ankles and legs. This is due to the build-up of excess fluid in the legs. The liver may also become enlarged.
Other symptoms of heart failure (on either side of the heart) can include:
• Feeling sick
• Loss of appetite
Depending on the underlying cause for the heart failure, one may also have other symptoms. For example, chest pains if one has angina, palpitations if there is a heart rhythm problem, etc.
How is heart failure diagnosed?
On examining a patient, a doctor may find signs that occur with heart failure. For example, an enlarged heart, a faster than normal pulse or signs of fluid retention (such as swollen ankles, an enlarged liver or crackles (abnormal sounds) in the lungs when the chest is examined). However, these signs and the symptoms mentioned above can be due to various conditions other than heart failure. Therefore, if heart failure is suspected, tests are usually done to confirm the diagnosis.
Tests that are usually done include an electrocardiograph (ECG, sometimes called a heart tracing). An echocardiogram is also done (an ultrasound scan of the heart). This painless test can usually confirm the presence of heart failure and can often diagnose the cause of the heart failure. A blood test to check for a substance called natriuretic peptide(BNP) may be done in some cases, as this tends to be raised in people with heart failure. Other tests such as a chest X-ray, a urine test or other blood tests may also be advised to rule out other causes of the symptoms.
What can be done?
• Diet. If the patient is overweight, losing weight can reduce the extra burden on your heart. Reducing salt in diet, as salt can cause water retention.
• Quit smoking. The chemicals in tobacco cause blood vessels to narrow, which can make heart failure worse. Smoking can also make IHD worse.
• Exercise. For most people with heart failure, regular exercise is advised. The fitter the heart, the better it will pump. The level of exercise to aim for will vary from person to person. Before increasing exercise, a doctor should be consulted, as some people with heart valve problems should not exercise.
• Immunisation. Patients should have an annual influenza jab and be immunised against the pneumococcal bacterium.
• Checking weight each morning in the case of moderate-to-severe heart failure. If a patient retains fluid rapidly, his/her weight goes up rapidly too. So, if the weight goes up by more than 2 kg (about 4 lb) over 1-3 days, a doctor should be contacted. An increase in medication may be needed.
What medicines are used to treat heart failure?
The following medications are commonly used to treat heart failure. They will be tailored to the individual person, depending on the cause and severity of the heart failure.
• Angiotensin-converting enzyme (ACE) inhibitors These medicines prevent a build-up of fluid by interfering with the enzyme angiotensin (a body chemical) which is involved in regulating body fluid. ACE inhibitors also have a protective effect on the heart, and may slow down the progression of heart failure. In some patients, use of ACE Inhibitors can cause cough. Patient who can’t tolerate ACE Inhibitors can have ARB as alternative. They work in almost the same way. They are relatively less useful but have fewer side effects.
• Beta-blockers. These are usually prescribed in addition to an ACE inhibitor. Like ACE inhibitors, beta-blockers have a protective effect on the heart. A low dose is started at first, and then increased every few weeks until a regular dose is reached. Occasionally, beta-blockers cause an initial worsening of symptoms before symptoms improve.
• Diuretics (‘water tablets’) A diuretic is commonly needed to ease fluid retention. This is taken in addition to an ACE inhibitor and beta-blocker. Diuretics work on the kidneys and make you pass out extra urine. This helps to clear excess body fluid that builds up. Diuretic medicines are normally taken in the morning. This is so the extra toilet trips are during the day, and not at night.
• Mineralocorticoid/aldosterone receptor antagonists (MRAs) (Special type diuretics): These medicines also prevent the build-up of fluid. They interfere with the enzyme which is involved in regulating body fluid. Research has shown that they improve your outlook. They may reduce your risk of needing to be in hospital and extend your life expectancy. If your kidney function is not good, you may not be able to take these medicines. Regular blood tests are used to monitor how your kidneys are coping.
ACE inhibitors, ARB, diuretics and special type diuretics (MRA) can cause renal (kidney) impairment and therefore it is imperative that renal function tests are regularly done to monitor and therefore prevent renal dysfunction.
Note: it is very important that you take the tablets that have been prescribed for you. You should discuss with your doctor if you stop taking any of your tablets.
Devices for heart failure
Various devices are implanted in a small number of people with heart failure who have reduced function of their left ventricles. Examples include implantable cardioverter defibrillators (ICDs) and pacemakers.
ICDs work by detecting any abnormal heart rhythms that may occur. If your heart rhythm is too slow, the device can give your heart extra support by working as a normal pacemaker. If your heart beats too fast, the ICD can give you a burst of extra beats at a slightly faster rate which should return your heart back to a normal rhythm, or it can give you a shock (defibrillation) to restore a regular heartbeat.
Pacemakers work differently. In some cases, there is some damage to the specialised heart cells that carry the signals needed for your heart to contract properly. This can then cause the signals to travel out of synch which leads to your heart pumping less forcefully and less efficiently. The pacemakers work to control these signals so the heart can then beat more effectively. This is also known as cardiac resynchronisation therapy.
Your doctor will be able to discuss with you in more detail if you are suitable for one of these devices.
What is the outlook (prognosis)?
It is difficult to give an outlook for an individual. In general, the more severe the heart failure, the worse the outlook. In many cases, the symptoms remain at a stable level for quite some time (months or years) before becoming worse. In some cases, the severity and symptoms become gradually worse over time.
Over a period of 15 years or so, various new treatments have been introduced which have led to a much improved outlook for people with heart failure.