Heart Failure
Heart failure means that your heart is
unable to pump enough blood to your body’s tissues and organs to meet their
needs.
The word 'congestive' refers
to the fluid build-up that occurs as the failing heart pumps out less and less
blood.
Should
your heart fail, you'll experience shortness of breath, fatigue and swelling of
the feet, ankles and abdomen.
The
mainstay of treatment is medication and lifestyle changes, but surgical
procedures are becoming part of the therapeutic options.
Description
Heart failure occurs when your heart muscle doesn't contract strongly
enough to pump enough blood to meet the body’s demands. "Failure" doesn't mean
that the heart has stopped pumping, but that it does not pump effectively
enough.
The
heart is essentially a pump that circulates blood around the body. It pumps
oxygenated blood to the body and deoxygenated blood to the lungs.
The
heart has two main chambers, the right and left ventricle. Heart failure is most
often caused by a poorly functioning left ventricle, the chamber that receives
oxygen-rich blood from the lungs and pumps it out to the body.
Normally, the left ventricle pumps out more than half the blood it contains with
each heartbeat (this volume is called the ejection fraction). When you
have heart failure, the left ventricle pumps less blood than normal (30% to 40%
or less).
As a
result of the weakened pumping ability of the left ventricle (left-sided heart
failure), a large portion of blood remains in the ventricle at the end of each
contraction. This leaves little room for incoming blood from the lungs during
the next heartbeat. Therefore, blood builds up inside the heart and lungs. This
leads to symptoms of heart failure, such as shortness of breath.
With
time, the right ventricle (which receives oxygen-poor blood from the body) pumps
out less blood to the congested, blood-logged lungs, leading to a build-up of
blood in the right ventricle. This in turn leaves less space for incoming blood
from the body, causing blood to back up in the body (right-sided heart failure).
This process results in swelling of the legs and abdomen.
When
your heart doesn't pump normally, your hormonal and nervous systems try to make
it pump more blood by increasing blood pressure, retaining sodium (salt) and
water in the body, and increasing the heart rate. These responses are called
compensatory responses, referring to the body's attempt to compensate for the
poor blood circulation and back-up of blood and fluids. These compensatory steps
may initially be of benefit, but eventually worsen the whole situation by
contributing to congestion and reducing the percentage of blood pumped with each
heartbeat (ejection fraction).
There
are several different types of heart failure, depending on whether the left or
right side of the heart is impaired, and whether the filling (diastolic) or
pumping (systolic) function of the heart is not working properly. The most
common form of heart failure is due to a problem with the pumping (systolic)
ability of the left ventricle. This condition is called left ventricular
systolic dysfunction.
Cause
Congestive heart failure is frequently the end result of many
cardiovascular problems. Its most common causes include:
Ischaemic
heart disease – blockages of blood vessels in the heart with decreased oxygen
supply to the heart muscle
Hypertensive
heart disease – damage to the heart muscle from longstanding high blood pressure
Cardiomyopathy
– a diseased heart muscle, often from an unknown cause
Valvular
heart disease – heart valve problems putting strain on the heart muscle
Arrhythmia-induced
heart disease – abnormal heart rhythm, leading to heart muscle damage
Congenital heart disease –
inborn abnormalities of the heart
Toxin-induced
heart disease – exposure of the heart to various toxins such as prolonged
alcohol abuse
Constrictive pericarditis – a
disease of the sac surrounding the heart
Symptoms
At first, symptoms of heart failure may be absent although your
internal pump is failing. Then gradually symptoms do occur because:
The
body is not getting enough oxygen and nutrients.
Blood backs up into the lungs and
body.
Compensatory responses occur,
including tightening of the blood vessels and retaining of fluid in the body
tissues, called oedema.
The earliest and most common symptoms of heart failure are lung or
systemic congestion, which causes the following symptoms:
Shortness of breath while lying down
that is relieved by sitting or standing up. A person may wake up coughing and/or
wheezing, with a rapid heart rate, and the feeling of being suffocated.
Difficult breathing and shortness of breath may occur during routine activities
or exercise that did not previously cause breathing problems.
Dry,
hacking cough, especially when lying down
Fluid
build-up (oedema), especially in the legs, ankles, and feet
Dizziness,
fainting, fatigue, or weakness
Rapid weight gain (due to
fluid build-up)
Increased urination at night
Nausea,
abdominal swelling, tenderness, or pain may result from fluid build-up in the
abdomen
Swollen
or distended neck veins
Prevalence
The good news – death rates from stroke and heart attack are on the
decline. The bad news – the death rate from congestive heart failure is
increasing. How can this increase in congestive heart failure be explained in
the face of improving medical and surgical treatment?
Previously, if a person had heart disease, such as a valve abnormality, he or
she would die at an earlier age, long before heart failure would develop. With
better medical care and treatments available, heart disease is now identified
and treated earlier, extending the lives of millions of people. However, people
with heart disease who now live longer have increased chances of developing
heart failure. Early diagnosis and treatment of heart failure is important to
prevent complications, hospitalisation and early death.
Course
Chronic congestive heart failure is a life-long, progressive
condition that may require many lifestyle changes and chronic medication.
Adherence to the prescribed drug regimen can reduce the impact of heart failure
on quality and length of life.
Symptoms
of chronic heart failure may be minor and occur only during strenuous activity
or exercise. Over time, symptoms worsen until they are present all the time,
even during rest. Breathlessness, swelling, and fatigue will increase; however,
treatment may help minimise these symptoms and the impact they have on your
life.
Long-term complications of heart failure are generally due to:
Chronic fluid build-up, which may involve:
Lung
congestion, ranging from mild to severe, with associated shortness of breath
Fluid
build-up in the abdomen and liver, which can lead to liver problems or failure
Breakdown
of skin (ulcers), especially in the legs, due to ongoing fluid build-up (oedema)
Cardiac arrhythmia (an abnormal heart
rhythm) due to a disturbance in the electrical conducting system of the heart
Stroke, when the increased stasis of
blood in the failing heart causes a blood clot in the heart, and this travels to
the brain
Organ
failure, such as kidney failure, due to decreased blood and oxygen supply to the
body
Death
related to the inability of the failing heart to provide the vital (life
sustaining) organs with oxygenated blood
Risk
Factors
A range
of cardiovascular problems may lead to congestive heart failure.
If you suffer from any of these diseases, you are at risk of
developing heart failure:
Ischaemic heart disease
Hypertensive heart disease
Cardiomyopathy
Valvular heart disease
Arrhythmia-induced
heart disease
Congenital heart disease
Toxin-induced heart disease
Constrictive pericarditis
When to
see a doctor
Seek care immediately for symptoms of sudden heart failure:
Severe shortness of breath
(trouble breathing, even when resting)
A sudden episode of prolonged,
irregular heartbeat with dizziness, nausea, or fainting
Foamy, pink mucus with coughing
A
sense of impending doom related to the heart or lungs not functioning well
Call your doctor
soon if you have symptoms of heart failure, which include:
Difficulty breathing during
routine activities or exercise that did not previously cause problems
Shortness
of breath when you lie down
Waking up at night short of breath or
feeling as if you are suffocating
Dry, hacking cough,
especially when you lie down
Rapid
weight gain (1,3 to 1,8 kg or more in just a few days; unrelated to diet)
Skin
sores developing as a result of fluid accumulation in the body (especially
common in the legs)
Diagnosis
The health professional may do the following investigations:
History
and physical examination
Laboratory tests
Electrocardiogram
Chest X-ray
Echocardiography
Radionucleotide
ventriculogram
History and physical examination
In obtaining a medical history, the health professional will ask
about the following:
Symptoms
(such as shortness of breath, swelling, cough)
Recent or past illnesses
(such as heart attack, viral illness, high blood pressure, diabetes)
Effort
tolerance (how much exercise can you do before becoming tired)
Ability to sleep flat and ability to
perform routine activities
The
following parts of the physical examination are most helpful in diagnosing
congestive heart failure:
Measuring blood pressure (to detect
high blood pressure) and pulse rate (to detect any abnormal heart rhythm)
Checking
the veins in the neck for swelling or evidence of high blood pressure in the
arteries of the eye
Listening
to breathing (crackles can be heard in the lungs when they are congested with
fluid) and heart sounds (an extra heart sound can be heard in a failing heart
and valve lesions will result in blood flow turbulence heard as murmurs)
Checking
the abdomen for swelling due to fluid build-up and for enlargement of or
tenderness over the liver
Checking the legs and ankles for
swelling due to fluid build-up
Measuring body weight (rapid
fluctuations are usually associated with change in body water content)
If the
person has symptoms typical of heart failure, the physical examination may be
all that is needed to make the diagnosis. However, additional tests will be
needed to determine the specific cause and type of heart failure and the extent
of damage to the heart.
Laboratory tests
In some cases, the results of laboratory tests may reveal a cause or
trigger of heart failure or give an indication of its severity. These tests
include:
Full blood count – detects the
presence of anaemia (low red blood cell count), which can cause or aggravate
heart failure.
Urea, creatinine and electrolyte level
measurement – a measure of kidney function that indicates how well the heart is
perfusing the kidneys; also indicates whether fluid retention is primarily due
to a kidney rather than a heart problem.
Liver
function test – measures various enzymes released from a damaged liver when
congested; also measures the levels of a protein called albumin in the body (low
levels of albumin can also lead to fluid build-up).
Blood
glucose measurement – high levels may indicate diabetes.
Thyroid function tests – abnormal
thyroid function can lead to heart damage.
Urine
analysis – protein or red blood cells in the urine may indicate kidney damage.
Electrocardiogram
An electrocardiogram (ECG) is a recording of the electrical activity
of the heart. This test is helpful in evaluating the heart and can show an
abnormal heart rhythm, enlargement of the heart chambers and evidence of poor
blood supply to the heart muscle.
Chest X-ray
A chest X-ray (CXR) produces a photographic image of the heart and
lungs. The picture is created using rays of energy that pass through the body
and project an image on a film. An X-ray can show information about the size and
shape of the heart (the heart usually enlarges in congestive cardiac failure)
and evidence of congestion in the lungs.
Other
findings may suggest that shortness of breath is caused by lung disease rather
than heart failure.
Echocardiography
Echocardiography (Echo) is an investigation that uses high-pitched
sound waves sent through a device called a transducer to produce a live, moving
image of the heart on a screen. (This technology, also called ultrasound
imaging, is the same as that used to view an unborn baby inside the mother's
womb.) Echocardiography is used to evaluate the ability of the left ventricular
chamber to relax, fill with blood and then pump the blood out to the body. A
measurement of the amount of blood pumped out of the left ventricle with each
heartbeat is obtained and indicates the severity of left ventricular
dysfunction. Echo also helps evaluate heart size and heart valve function.
Radionucleotide ventriculogram
During a
radionucleotide ventriculogram, a radioactive substance (radioisotope) is
injected into a vein. This substance then circulates in the blood stream to the
heart. Due to its radioactive nature, special screening devices can detect the
substance as it moves through the body. Ventriculography evaluates how
effectively the left ventricle is pumping and measures the percentage of blood
pumped out of the left ventricle with each heartbeat.
Treatment
In some patients, congestive heart failure can be improved and even
cured by treating the underlying disease process. An example of this would be
valvular heart surgery in a failing heart with a valve abnormality.
However,
in many other patients the underlying problem cannot be solved. The goal of
treatment is therefore to prevent further damage to the heart and to improve its
pumping ability. This is usually achieved with medication and lifestyle
modification, but surgery is being evaluated as another treatment option.
Medications
Angiotensin-converting enzyme (ACE) inhibitors
Angiotensin Converting Enzyme (ACE) inhibitors, Angiotensin
Antagonists, Beta blockers and Spirinolactone are drugs used in the treatment of
heart failure, which have been proven in clinical trials, not only to improve
symptoms, but also the long-term outcome (prognosis) in patients with heart
failure. Diuretics and Digoxin, while improving symptoms, do not influence the
long-term prognosis. They're the only drugs clearly proven in various medical
trials to help people with the disease feel better and live longer. The drugs
include captopril, enalapril and ramipril.
ACE
inhibitors help the failing heart by relaxing the arteries in the body. This
allows blood to flow from your heart more easily. They also decrease sodium and
water retention.
ACE
inhibitors cause an irritating cough in about 20% of people taking them. But it
may be best to put up with the cough, if you can, to gain the medications'
benefits.
Diuretics
Often called "water tablets", diuretics make you urinate more
frequently and prevent fluid from collecting in your lungs and elsewhere in your
body. An example of a commonly prescribed diuretic is furosemide.
Digoxin
Digoxin, also called digitalis, increases the strength of your heart
muscle contractions. While digoxin doesn't improve overall survival rates, it
reduces heart failure symptoms and improves your ability to function with the
condition.
Beta-blockers
Beta blockers approved for the treatment of congestive heart failure
are carvedilol, metoprolol and bisoprolol, although carvedilol appears to be the
drug of choice. These agents reduce the risk of death from progressive pump
failure as well as the risk of sudden death.
Angiotensin II antagonists
Angiotensin II (AT-II) antagonists (losartan, valsartan) work
similarly to ACE inhibitors but don't cause a persistent cough. Recent trials
suggest these agents to be of similar efficacy as ACE inhibitors in the
treatment of heart failure, but in general there use is limited to those
intolerant of ACE inhibitors.
Life-style changes
The following life-style changes are important in controlling the
symptoms of heart failure and may play a role in preventing disease progression:
Restriction of salt intake
Salt, but more specifically the sodium contained in it, causes you to
retain fluids. You also need to be careful when using salt substitutes.
Limiting fluid intake
If you have congestive heart failure your body will retain excess
fluid. In order to minimise fluid build up and reduce the amount of diuretics
you need, it is important to restrict your fluid intake to less than 2 litres
per day.
Limiting alcohol intake
If it is thought your heart failure is due to excess alcohol intake,
it is very important to abstain totally from all alcohol. Continued use will
lead to worsening heart failure. Patients with heart failure from other causes
should limit their alcohol use to one or two units per day.
Weight monitoring
You should weigh yourself every morning. Rapid weight increase of 1
or 2 kg may indicate excessive fluid retention. Contact your doctor if this
happens, because your medication may need to be changed.
Exercise
Exercise was once contra-indicated in people with heart failure, but
studies have shown that moderate exercise helps your heart pump more efficiently
and reduces the demands on your heart muscle. Before you start exercising, talk
to your doctor about the best type of exercise for you and warning signs that
you've done too much and should stop.
Surgical procedures
Researchers continue to search for new and better ways to treat
congestive heart failure. Some surgical procedures being studied include:
Heart pumps
Mechanical heart pumps, called ventricular assist devices, are
implanted into your chest and attached to your weakened heart to help it pump.
This is a temporary procedure used to keep heart transplant candidates alive
while waiting for a donor heart.
"Heart reduction" surgery
As the left ventricle becomes weaker, it enlarges further. This
compromises its pumping ability. A procedure called partial left ventriculectomy,
or heart reduction surgery, can sometimes be performed. This involves removing a
portion of your enlarged heart muscle and "remodelling" your heart to its
near-normal size and shape. In theory, this should help your heart pump more
efficiently. The potential role of this operation is not yet well understood,
but research continues.
"Wrap-around" surgery
In the "wrap-around" procedure, called cardiomyoplasty, a piece of
back muscle is removed and wrapped around your heart. It is then stimulated
electrically to contract rhythmically with your weakened heart muscle. Again,
what role, if any, this procedure may have in treatment is not yet known.
Heart transplant
If all other treatment modalities fail, a heart transplant is an
option. Survival and quality of life following a transplant are excellent, but
there's a shortage of donor hearts and the recipient will be on life-long immuno-suppressive
treatment. Candidates for transplantation are typically younger patients (under
65 years of age) who are free of other serious diseases and whose other vital
organs are healthy.
Xenotransplantation
Researchers are exploring the possibility of transplanting
genetically manipulated pig hearts into humans with congestive heart failure.
Clinical trials could begin in the three to five years in the United States.
Prevention
The best way to prevent congestive heart failure is to adapt a
healthy lifestyle that protects your coronary arteries against atherosclerosis
(build-up of cholesterol, and narrowing and hardening of the arteries). It is
also important to control medical conditions such as high blood pressure and
diabetes.
Atherosclerosis in the heart's blood vessels (coronary artery disease) is a
leading cause of congestive heart failure. To reduce your risk of developing
atherosclerosis:
Don't smoke. If you do smoke, quit.
Smoking greatly increases your heart disease risk.
Watch
your cholesterol level. If it is over 200 mg/dl (5.17 mmol/L), follow your
doctor's advice for lowering it. A low-cholesterol diet, exercise and quitting
smoking will help keep your cholesterol low.
Keep
your blood pressure low. If your blood pressure is over 140/90 mm Hg, you run a
higher risk of heart disease. Exercising, limiting alcohol intake and
controlling stress will help keep your blood pressure in the healthy range.
Exercise
regularly. Apart from the benefits mentioned above, it will help control your
weight and your stress levels, all of which will help keep your heart healthy.
Control
diabetes by taking your medications as directed.
