Heart failure occurs when the heart muscle fails to pump as much blood as the body needs. The faulty pumping means the body doesn't get the oxygen it needs. Pressure in the heart increases and the patient is aware of breathlessness.
Heart failure is usually caused by a problem with the left ventricle. Normally, it pumps out more than 50% of the blood that fills it during each heartbeat. In most heart failure patients, it pumps out less than 40% of the blood that fills it during each heartbeat. As a result, a large portion of blood remains in the chamber, and there is less room for blood coming from the lungs during the next heartbeat. Blood may back up inside the heart and lungs. The heart's lower right chamber may also not be working well.
When the heart does not pump normally, the patient's hormone and nervous systems try to respond. The body may raise the blood pressure, hold on to salt and water and make the heart beat faster. The muscular walls of the heart may get bigger and thicker. At first, all these reactions may help. In time, however, the heart is no longer able to keep up. The symptoms then get worse.
Many people with severe heart disease in time develop heart failure. When and how it develops depends on the type of underlying heart disease.
Although patients with heart disease are living longer, they now have a greater chance of developing heart failure.
The prevalence of heart failure is increasing with the majority of cases due to coronary heart disease (CHD) and hypertensive heart disease,
- Heart failure affects one in 1000 people each year - and is rising by 10% a year
- Figures suggest 0.5 per cent of the population – 140,000 people - have undiagnosed heart failure
- Incidence of heart failure varies considerably between primary care trusts - from 0.9% to 5%.
- Heart failure accounts for approximately 5% of medical admissions
- Around half of all patients admitted with heart failure are readmitted within three months
- Over the next 20 years prevalence is expected to increase by 20% due to the rising proportion of older people and more people surviving heart attacks.
Symptoms of heart failure
Heart failure can affect persons of any age, even young children, especially if they are born with a heart defect. It most often affects older persons who may already have hearts weakened by age-related conditions or disease.
In the early stages of congestive heart failure, a person may have no symptoms. When symptoms do develop, they may include:
- A dry, hacking cough, especially when lying down
- Confusion, sleepiness and disorientation may occur in older people
- Dizziness, fainting, fatigue or weakness
- Fluid build up, especially in the legs, ankles and feet
- Increased urination at night
- Nausea, abdominal swelling, tenderness or pain (may result from the buildup of fluid in the body and the backup of blood in the liver)
- Weight gain (due to increase in fluid)
- Weight loss as nausea causes a loss of appetite and as the body fails to absorb food well
- Rapid breathing, bluish skin and feelings of restlessness, anxiety and suffocation
- Shortness of breath and lung congestion as the blood backs up in the lungs
- Tiring easily
- Wheezing and spasms of the airways similar to asthma
Causes of heart failure
Heart failure is generally the result of another disease, such as:
- Coronary artery disease
- Disorders of the heart's electrical conduction system
- Heart valve disorders
- Kidney failure, which causes fluid to build up in the blood stream, making it harder for the heart to work
- A blood clot in an artery of the lungs
- An over- or underactive thyroid gland, which can speed up or slow down the pumping of the heart, causing it not to completely fill or empty as it should
- Certain lung disorders
- Certain parasites that get into the heart muscle in tropical countries
- Constrictive pericarditis
- Untreated or inadequately treated high blood pressure
Diagnosing heart failure
A doctor will diagnose heart failure using:
- An electrocardiogram and chest X-ray
- An echocardiogram
- A blood test for BNP that is increased in heart failure
Treating heart failure
Treating conditions, such as high blood pressure, thyroid disorders and coronary artery disease, as early as possible can help prevent heart failure. Treatment depends on the cause of the heart failure, how severe the symptoms are and how well the body is able to make up for the heart's not being able to pump enough blood. While heart failure cannot be cured or made to go away, it is possible to make physical activity more comfortable, improve the quality of the life and prolong life.
Heart failure treatments focus on:
- Treating the underlying disorder that may be causing heart failure
- Controlling the elements that can make heart failure worse
- Treating the heart failure itself
- Drugs. In most cases, patients with heart failure have the condition for the rest of their lives and require specific drugs. A combination of drugs may be used, including ACE inhibitors, ARBs, diuretics,beta-blockers, aldosterone antagonist and occasionally digoxin. These do not cure heart failure. They can relieve symptoms, improve heart function, slow the progress of the disease and reduce the risk of complications, hospitalisation and premature death.
- Some patients may benefit from biventricular pacing which is a type of pacemaker that coordinates the pumping of the lower left and right chambers. Less blood leaks through the mitral valve and the left ventricle pumps more effectively.
- Surgery to bypass blocked blood vessels in the heart can restore normal blood flow (CABG).
- Surgery to correct certain types of heart valve disease may also improve symptoms of heart failure. This applies to some patients with a leaky mitral valve (mitral regurgitation).
- Ventricular assist devices (VAD) are machines that help a failing heart pump blood through the body.
- Heart transplantation may be needed for a small number of patients with severe heart failure.
- In most heart failure patients, treatment is also needed to correct or control related health problems (such as high blood pressure or coronary artery disease) and any other heart failure triggers (such as fever, anaemia or infection)
- Lifestyle changes, such as losing weight, starting an exercise program, reducing the amount of salt and fat in the diet, stopping smoking and avoiding alcohol.
Heart failure that develops or gets worse quickly needs to be treated on an emergency basis in a hospital. If there is fluid in the lungs, oxygen will be given through a face mask. Diuretics can be injected, and drugs (such as GTN) can be given to improve comfort. In some cases it may be necessary to use a mechanical ventilator to assist in breathing. Certain hormones similar to adrenaline can be given on a short-term basis to help the heart muscle work more effectively.