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NASPE-Heart
Rhythm Society is located at Six Strathmore Road, Natick, MA 01760
Phone: 508-647-0100 Fax: 508-647-0124
Copyright © NASPE-Heart Rhythm Society
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Heart Failure
Risk Factors
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| There are a
number of diseases, medical conditions and other factors that put
people at higher-than-average risk for heart failure. Not everyone with
these risk factors develops heart failure, but they put extra stress on
the heart that may lead to the condition. The odds of developing heart
failure are especially high in people who have more than one of these
risk factors.
Coronary Artery Disease (CAD)
Like all the organs and tissues of the body, the heart needs oxygen and
other nutrients carried by the blood to remain healthy. When the blood
vessels become narrow or clogged so that not enough blood reaches the
heart, damage is done to the heart muscle which, in turn, may affect
its ability to pump blood efficiently. The most common cause of CAD is
arteriosclerosis (sometimes called "hardening of the arteries"), a
condition in which cholesterol and fatty deposits called "plaque" build
up in the arteries. CAD also may be caused by blood clots that lodge in
the arteries and interfere with the normal flow of blood. |
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A substance called arteriosclerotic plaque clogs the blood vessel.
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Past
heart attack (myocardial infarction)
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| A heart attack occurs when an
artery that supplies blood to the heart is blocked so that no oxygen
reaches the heart muscle. When this happens, part of the heart "dies"
(the area of dead muscle is called an "infarct"). The remaining,
healthy tissue must take over the job of pumping blood, an extra burden
that may weaken the heart's pumping ability. |
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Heart Rhythm Disorders
(arrhythmias)
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| When the heartbeat is too
fast, too slow or irregular (out of rhythm), it may not be able to pump
enough blood to meet the needs of the body. In these cases, once the
underlying problem is identified and treated, the symptoms of heart
failure may go away before significant damage is done to the heart
muscle. |
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A normal heart rhythm (left).
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| The abnormal rhythm (right) is a
potential cause of cardiac arrest. |
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Alcohol and Drug Abuse
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| Excessive use of alcohol, or
abuse of drugs such as cocaine and amphetamines place added stress on
the heart that can lead to heart failure or other heart diseases. These
substances also can damage the cells of the heart. Some environmental
toxins and prescription drugs also can contribute to the problem. |
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Abnormal heart valves
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| The valves that open and close
to allow blood to pass between the chambers of the heart may be damaged
by disease or infection (endocarditis). Sometimes, heart valve defects
are present at birth. Whatever the cause, if the valves don't open or
close completely with each heartbeat, the heart muscle has to pump
harder to keep the blood moving. If the workload becomes too great,
heart failure can develop. |
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Heart muscle disease
(cardiomyopathy) or inflammation (myocarditis)
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| Any damage to the heart muscle
itself increases the risk of heart failure. Heart muscle disease or
infection may be caused by a number of factors, including congenital
problems (defects present at birth), drug or alcohol abuse, bacterial
or viral infections or other, unknown reasons. |
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Heart defects present at birth
(congenital heart disease)
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| If the heart and its chambers
don't form correctly in the developing fetus, the normal parts of the
heart must make up for defects by working harder. Over time, the added
stress may cause healthy structures to "fail" and lead to HF. |
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Diabetes
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| Diabetes tends to increase the
levels of cholesterol and triglycerides -- unhealthy fats that
contribute to coronary artery disease. People with diabetes also are
more likely to be overweight and have high blood pressure. These
factors must be carefully monitored and controlled because they put
extra strain on the heart and can lead to heart failure, as well as to
other cardiovascular diseases, such as heart attack and stroke. |
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High blood pressure
(hypertension)
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Uncontrolled high blood
pressure doubles a person's risk of developing heart failure. If the
pressure created by blood flow through the vessels of the circulatory
system is too high, the heart has to pump harder to keep the blood
circulating. Over time, the extra burden can thicken the heart muscle
and eventually weaken the heart. |
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Sometimes, an otherwise
healthy heart may temporarily have trouble keeping up with the body's
need for oxygen and other nutrients carried by the blood because of
problems unrelated to the cardiovascular system. These problems are
less common than other causes for heart failure, but it is important to
monitor heart function in people who have:
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An abnormally low number of red
blood cells (severe anemia)
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| It is the job of the red cells
to carry the oxygen needed to maintain life in all the cells of the
body. If there are not enough of these cells, the heart pumps at a
faster rate to circulate the smaller number of red cells quickly enough
to supply the oxygen the body needs. Over time, the extra burden may
lead to heart muscle damage. |
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An overactive thyroid gland
(hyperthyroidism)
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| The thyroid gland affects the
rate at which the body metabolizes food and other substances. If the
thyroid is overactive, the body works at a faster pace, and the heart
may be overworked as it adjusts to keep up with the body's increased
demand for oxygen and other nutrients. Waste products also build up
more quickly in the cells, and must be picked up by the circulating
blood and carried to the kidneys, liver and elsewhere to be processed
and excreted. |
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Lifestyle Factors that Increase the
Risk of HF
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TREATMENTS Heart Failure
Treatment
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Although heart failure (HF) is a serious
condition that may get worse over time, in some cases
it can be reversed. Underlying problems such as heart
valve disease, high blood pressure, abnormal heart rhythms
or coronary artery disease may be treated before significant
damage is done to the heart.
Even when the heart muscle is impaired, there are now
a number of treatments to relieve symptoms and stop
or slow down the gradual worsening of heart failure.
In some cases, the function of the heart can be improved.
The treatment prescribed for each individual depends
on the type, cause, symptoms and severity of heart failure.
Usually, more than one therapy is used.
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Therapy for Underlying Diseases
A top priority in the treatment of heart failure is
to treat the conditions that contribute to the disorder.
For example, surgery or angioplasty may be performed
to open clogged blood vessels in patients with coronary
artery disease, and medications prescribed to control
high blood pressure, diabetes, anemia or thyroid disease.
Heart failure often impairs the
electrical system
that controls the normal, steady rhythm of the heartbeat.
Abnormal electrical signals that arise from damaged
heart muscle may cause a heartbeat that is too slow
(bradycardia), too fast (tachycardia) or irregular.
Arrhythmias are common in heart failure patients.
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It is particularly important
to treat abnormal heart rhythms (arrhythmias)
in patients with heart failure.
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The Role of Electrophysiology
Electrophysiologists are cardiologists who have additional
education and training in the diagnosis and treatment
of abnormal heart rhythms. Close collaboration between
these specialists and other doctors who treat patients
with heart failure is important. For example, some of
the drugs that are used to treat arrhythmias also decrease
the heart's pumping ability. This can cause heart failure
to become worse and lead to more arrhythmias. The goal
of therapy is to treat abnormal heart rhythms and heart
failure together.
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Electrophysiologists
create "heart maps" that pinpoint the sites that
give rise to abnormal heart rhythms.
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Treatments for arrhythmias may include:
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Implanted devices range
in size from that of a half- dollar to the size
of a small beeper.
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Implanted devices |
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Catheter ablation |
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Medications |
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Remarkable advances in the technology and function of
implanted cardiac devices have been achieved over the
past 10 years. The devices also have decreased in size.
Now, they are being studied in clinical trials as treatment
for patients with heart failure who are at risk of developing
heart rates that are too rapid or too slow because of
progressive muscle damage that can affect the heart's
electrical system.
Most of these devices can be implanted with minor surgery
that may be done as outpatient procedures, or requires
only a day or two in the hospital. Wires (leads) are
placed in the right upper and lower chambers of the
heart. A small computer, or microprocessor, is implanted
under the skin, usually near the collarbone. These remarkable
"built-in" computers have enormous potential to increase
survival and the quality of life for the patient with
heart failure. Heart failure patients may be treated
with permanent pacemakers, hemodynamic monitors, implantable
defibrillators (ICDs) or resynchronization devices.
Often, one or more of these features can be present
in a single or 'combined' device.
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Pacemakers are used to treat
a heartbeat that is too slow. This may be due
to heart muscle damage. Sometimes, the drugs prescribed
to treat heart failure slow the heart rate. In these
cases, a pacemaker may be needed to support the use
of medications. Traditionally, pacemakers are attached
to one or two thin wires (leads), which are placed in
the right upper and lower chambers of the heart. The
pacemaker continuously monitors the heart's natural
rhythm and stimulates (paces) one or both chambers if
the heart rate drops below a certain number of beats
per minute. The patient does not feel the electrical
signal that is sent from the pacemaker to the heart.
Modified pacemakers also are being used to directly
treat heart muscle weakness
(see resynchronization therapy)
in selected patients. Pacemakers have other features,
as well. They can detect arrhythmias before the patient
has symptoms, and lead to earlier diagnosis and treatment
of heart rhythm disorders.
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Implantable Cardioverter Defibrillators
(ICDs) are pacemaker-like devices that continuously
monitor the heart rhythm, and deliver life-saving shocks
if a dangerous heart rhythm is detected. They
can significantly improve survival in certain groups
of patients with heart failure who are at high risk
of ventricular fibrillation (VF). VF is a deadly heart
rhythm disorder that is the primary cause of
sudden cardiac death
(SCD).
ICDs also have the ability to act
as pacemakers for too-slow heart rates and can be modified
to provide resynchronization therapy.
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An
ICD is implanted in the shoulder area to deliver
a controlled electric shock if it detects a dangerous
heart rhythm.
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Heart failure patients who may benefit
from ICDs include people who:
- have survived cardiac
arrest
- have a rapid, recurrent heartbeat called sustained
ventricular tachycardia, or VT
- have a history of heart muscle damage caused by a prior
heart attack, and who also have non-sustained VT (a rapid
heart beat that stops on its own). An electrophysiology
study can determine which heart attack survivors are
at risk for cardiac arrest and may need an ICD. In clinical
trials, ICDs were of particular benefit for individuals
with cardiomyopathy (heart muscle damage) caused by a prior
heart attack.
- Have an ejection
fraction of 30 percent or lower. (A clinical trial of
heart attack survivors with low ejection fractions found
that ICD therapy saved lives compared to medications alone,
even in patients with no history of VT. The benefits were
so significant, the study recently was stopped early so that all
patients could have the option of an ICD).
Heart failure patients face a significant risk of sudden
cardiac death over the course of their disease. Other
clinical trials are under way to compare ICDs with conventional
drug therapy, and ICDs may soon be recommended for even more
patients with heart failure.
Catheter ablation (also called
radiofrequency ablation, or RFA). In this procedure, one or
more flexible, thin tubes (catheters) are introduced into
the blood vessels and directed under x-ray guidance to the
heart muscle. A burst of radiofrequency energy heats and destroys
very small areas of tissue that give rise to abnormal electrical
signals.
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Lifestyle Changes
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People with heart failure usually can
make lifestyle changes to improve their symptoms or
control some of the factors that contribute to heart
failure. For example, most people with HF will see
an improvement in their symptoms if they:
- get regular exercise,
including physical rehabilitation programs for
some patients. Exercise must be modified, however,
and patients must get plenty of rest when heart
failure symptoms are not stable. This avoids putting
too much stress on the heart.
- eat a "heart healthy"
diet that avoids sodium (salt), and is
low in fat, especially for patients with coronary
artery disease.
- don't smoke and
avoid exposure to secondhand smoke.
- do not drink alcohol,
or limit their intake to no more than one drink
two or three times a week.
- lose weight.
- avoid caffeine
or limit its intake.
- reduce stress.
- weigh themselves daily.
A sudden gain in weight means an increase in the
build up of fluids and may be a sign that their
condition is becoming worse.
- keep track of symptoms
and report any worrisome changes to their doctor.
- see their doctor frequently
for regular checkups to monitor the progress of
their condition.
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Medications
There are a number of medications for heart failure
that work in different ways, and most people take more
than one drug. Medications may be prescribed to:
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expand the blood vessels |
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reduce the amount of water and sodium (salt) in
the body, which reduces the workload on the heart |
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strengthen the heart muscle's pumping action |
Types of medication prescribed for heart failure
include: 
- Angiotensin converting enzyme (ACE) inhibitors.
These drugs counteract the action of certain hormones
that the body forms in response to heart failure and can
cause the condition to get worse. ACE inhibitors dilate,
or widen, the arteries. This improves the flow of blood
so the heart does not have to pump as hard to circulate
blood.
- Beta-Blockers lower blood pressure and decrease
the heart rate. This reduces the workload on the heart.
They also block the effects of hormones and help slow
the progression of HF, and prevent heart rhythm problems.
- Diuretics (water pills) help the kidneys produce
more urine and rid the body of excess fluid.
- Spironolactone is a type of diuretic that prevents
the loss of potassium. When used in patients with advanced
heart failure, it can reduce hospitalizations and prolong
life.
- Potassium and magnesium supplements are often
prescribed in combination with diuretics to replace the
excessive loss of these minerals, which are excreted in
the urine.
- Digoxin makes the heart beat stronger and slower,
and regulates the rhythm of its contractions.
- Anti-arrhythmic drugs treat abnormal heart rhythms.
Cardiac resynchronization therapy (CRT)
The U.S. Food and Drug Administration (FDA) recently approved
the first of a new type of pacemaker that paces both sides
of the heart simultaneously to coordinate their contractions
and improve their pumping ability. Heart failure patients
who have a delay in the electrical impulses to the lower chambers
of the heart, a condition called bundle branch block, are
potential candidates for this therapy. According to clinical
trial results with selected patients, cardiac resynchronization
therapy:
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Increased the amount of daily activities
patients could perform without experiencing the symptoms
of heart failure |
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Extended the exercise capacity of patients
with Heart Failure, as measured by the distance they could walk in
6 minutes |
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Improved the overall quality of life |
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Promoted changes in the anatomy of the
heart that improved cardiac function |
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Reduced the number of days patients spent
in the hospital, and the total number of hospitalizations
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How Does CRT Work?
In the
normal heart,
the electrical conduction system delivers
electrical impulses to the left ventricle in a highly organized
pattern of contractions that pump blood out of the ventricle
very efficiently. In some patients with systolic heart failure
caused by dilated cardiomyopathy (an enlarged heart) this
electrical coordination is lost. Uncoordinated heart muscle
function leads to inefficient ejection of blood from the ventricles.
CRT devices pace both the left and right ventricles simultaneously
to resynchronize the muscle contraction and improve the efficiency
of the weakened heart.
Clinical trials are under way to determine if resynchronization
therapy improves survival in heart failure patients, and whether
resynchronization devices work best if they are incorporated
into pacemakers or ICDs.
Implantable Hemodynamic Monitors
use pacemaker technology in which a pacing-type wire is placed
in the lower right chamber (ventricle) of the heart. This wire
has a sensor at the tip, which measures blood pressure in
the ventricle. It monitors the status of heart failure patients
and the effects of drug therapy. It provides information that
may make it possible to intervene early to diagnose and treat
worsening heart failure, before symptoms develop or hospitalization
is needed. The technology may be available in future pacemaker,
ICD and resynchronization devices.
Surgery
Surgery is used to treat underlying disease that contributes
to heart failure in some patients, such as:
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Coronary artery bypass graft (CABG) surgery
or angioplasty to prevent or treat heart failure caused
by blocked arteries. |
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Surgical implantation of an artificial
heart valve, or surgical valve repair. |
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Surgery to treat congenital heart defects. |
Surgical treatments for heart failure itself include:
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Recent advances in technology may make transplantation
of artificial hearts an option for more patients
in the future.
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Heart transplantation. Transplant
may be the best option for patients with the most severe
types of heart failure. This treatment is available to
only a small number of patients, however, because of the
shortage of donor hearts. |
| Left ventricular assist devices (LVAD)
may be implanted in the chest to increase the pumping
action of the heart. Until recently, LVADs required a
large, hospital-based console to which the patient was
attached while waiting for a transplant.
These devices are now smaller and may enable certain
patients to go home with them.
The devices may
be used as a primary treatment, or as a bridge to heart
transplant in adults. Clinical studies show that patients
with severe heart failure who receive an LVAD have a lower
risk of death than people who are treated with medications
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Miniaturized battery-powered LVAD units now
make it possible for many patients to leave
the hospital.
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Surgery to restore the shape and size of the heart
The electrical signals that cause the heart muscle to contract
move in a spiral pattern. The heart and its chambers are shaped
somewhat like a football - which can be thrown in a spiral
pattern. This is the ideal shape for the heart to receive
the signals that cause it to beat. In heart failure, however,
the heart often enlarges so that it looks more like a basketball.
The shape of the heart no longer "fits" the electrical pattern,
which makes it less efficient. A number of promising surgical
procedures are being investigated to address this problem
by reconstructing parts of the heart to make its shape more
normal. These procedures, often called
heart reconstruction surgery include:
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 Valve
repair and revascularization. Studies in which damaged
heart valves are repaired and/or the blood flow to damaged
areas of the heart is restored (revascularization) have
shown promise in reducing the size of the heart and improving
cardiac function in some patients with heart failure.
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Dynamic cardiomyoplasty.
In this procedure, one end of a muscle from the patient's
back is detached and wrapped around the ventricles of
the heart. After a few weeks, the relocated muscles are
conditioned with electrical stimulation to behave and
"beat" as if they were heart muscles. The procedure may
benefit the failing heart by improving its pumping ability,
limiting heart enlargement and reducing stress on heart
muscle. |
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The Batista procedure,
also called "partial left ventriculectomy," removes a
section of the wall of the left ventricle. The edges of
the ventricle are repositioned and sewed together, and
the mitral valve and valve parts are repaired or replaced.
This procedure is no longer performed by most surgeons,
however, because its long-term results have been poor. |
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The Dor procedure, also called "endoventricular
circular patch plasty" or EVCPP, is used when an aneurysm
forms in the ventricle following a heart attack. In the
surgery, a looped stitch is made that shrinks the area
of dead and scarred heart tissue where the aneurysm formed.
Sometimes, a patch made of Dacron or human tissue is used
to cover other areas of defective muscle. The goal of
the surgery is to return the ventricle to a more normal
size and shape. |
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The Acorn procedure involves slipping
a mesh-like "sock" around the heart and stitching it in
place to reduce the size of the heart or prevent it from
becoming any larger. | |
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