Congestive Heart Failure

What Is Congestive Heart Failure?
The heart is composed of two independent pumping systems, one on the left
side and one on the right. The right chamber, or right atrium, of the heart
relaxes and expands to fill with blood that has returned from the body. (This
relaxed action causes diastolic pressure, recorded as the second and lower
number when measuring blood pressure). The used blood is poor in oxygen and
rich in carbon dioxide. It enters a second muscular chamber called the right
ventricle, which pumps the blood into the lungs where it exchanges the carbon
dioxide for oxygen. This blood, now oxygen-rich, returns through pulmonary
veins to the left atrium in the heart where it is pumped back out to the body by
the left ventricle. The left ventricle has thicker muscles than the right in order
to perform contractions powerful enough to force the blood through the main
artery (the aorta) to all parts of the body. (This strong contraction causes
systolic pressure, the first and higher number measured for blood pressure.)
Congestive heart failure is not a disease but a condition that occurs when the
heart is unable to pump enough blood to meet the needs of the body's tissues.
When the heart fails, it is unable to pump out all the blood that enters its
chambers. To help determine severity, physicians use a calculation called an
ejection fraction, which is the percent of the blood pumped out during each
heart beat. An ejection fraction of 50% to 75% is normal. In most cases of
heart failure the left side fails, causing systolic dysfunction, in which fluid
backs up and accumulates in the lungs. The ejection fraction in such cases falls
below 40%; in severe failure it may drop as low as 5%. Right-sided heart
failure, which is much less common, causes diastolic dysfunction, in which
fluid entering the heart backs up, causing the veins in the body and tissues
surrounding them to swell. In such cases, the ejection fraction is paradoxically
normal or high. Given the interconnected nature between the chambers of the
heart, left-sided failure may ultimately precipitate failure in the right side of the
heart.
Heart failure can occur in several ways. The ventricle muscles of the heart
may become thin and weakened and dilate to the extent that they cannot pump
the blood with enough force to reach all the body's tissues. In other cases, the
heart muscles stiffen or thicken so they lose elasticity and cannot relax;
insufficient blood enters the chamber and so not enough blood is pumped out
into the body to serve its needs. Sometimes the valves of the heart, which
control the flow of blood leaving the heart, are abnormal; they may narrow,
causing a back-up of blood or they may close improperly so that blood leaks
back into the heart. Mechanisms that the body uses to compensate for
inefficient pumping action can, over time, change the architecture of the heart
and finally lead to irreversible problems. As a result of these changes, the
body's vital organs do not receive enough oxygen and nutrients, and the body's
wastes are removed more slowly; eventually vital systems break down.
What Causes Congestive Heart Failure?
Damage to the mechanisms that control the input to and output of blood from
the heart is usually the last stage of one of several heart or circulatory
diseases. Heart failure can be a direct result of one of these diseases or it can
occur over time as the heart tries to compensate for abnormalities caused by
these conditions.
Coronary Artery Disease
Congestive heart failure may develop slowly from heart damage due to
atherosclerosis, a build-up of cholesterol deposits on the walls of the arteries
supplying the heart muscle with oxygen. Heart failure in such cases most often
results from a localized pumping defect in the left side of the heart.
Damage After a Heart Attack
People now often survive heart attacks, but eventually many develop heart
failure from the physical damage done to the heart muscles by the attack.
Heart attack recovery is probably one of the major factors in the dramatic
increase in heart failure cases over the past decade.
High Blood Pressure
Uncontrolled high blood pressure, or hypertension, can cause a heart attack but
it is also a major cause of heart failure even in the absence of an attack. In
hypertension, the heart muscles thicken to compensate for increased blood
pressure, and over time the force of their contractions weaken and they have
difficulty relaxing, thereby preventing the normal filling of the heart with blood.
Researchers have detected a defect in animal heart cells, which causes them
to enlarge in response to high blood pressure. These enlarged cells undergo
molecular changes that result in calcium loss, a mineral crucial for healthy
heart contractions. The defect appears to be irreversible, making early
detection and reduction of high blood pressure extremely important preventive
measures. It should be noted, however, that the successful treatment of high
blood pressure is proving to be an effective measure for preventing heart
failure.
Diabetes
Diabetes contributes to heart failure, not only because of its association with
obesity, high blood pressure, and coronary artery disease, but also because
specific mechanisms that contribute to diabetes itself may also damage the
heart.
Valvular Heart Disease
The valves of the heart, which control the flow of blood leaving the heart, can
narrow, causing a back-up of blood, or they can close improperly, causing
blood to leak back into the heart. In the past, rheumatic fever, which scars the
heart valves and prevents them from closing, was a major cause of death from
heart failure. Fortunately, antibiotics have relegated this disease to a minor
cause of heart failure. Birth defects may also cause abnormal valvular
development.
Cardiomyopathies
Cardiomyopathies are diseases that damage the heart muscles and lead to
heart failure. Genetic factors or birth defects may play a role in the
development of these conditions.
Dilated Cardiomyopathy. Dilated cardiomyopathy involves an enlarged heart
ventricle, in which the muscles thin out rather than becoming thick, causing
reduced systolic blood pressure. Although this condition is also associated with
a genetic factor, the cause is often not known (in which case it is called
idiopathic dilated cardiomyopathy). Research is strongly indicating that many
cases may be the result of an autoimmune response, in which infection-fighting
antibodies attack a persons own proteins in the heart, mistaking them for
foreign agents.
Hypertrophic Cardiomyopathy. In hypertrophic cardiomyopathy, the heart
muscles become thick and contract with difficulty. Some research indicates
that this occurs because of a genetic defect that causes a loss of power in
heart muscle cells and, subsequently, diminished pumping strength. To
compensate for this power loss, the heart muscle cells grow. This rare
condition is the cause of many occurrences of sudden death in young athletes.
Other Causes
Alcoholism may also produce heart failure, since chronic abuse can damage
the heart muscles or cause hypertension. Severe emphysema is a major cause
of right-sided congestive heart failure. Other less common causes of heart
failure include excessive salt consumption, hyperthyroidism, thiamin deficiency,
pneumonia, high fever, and failure of the liver or kidneys. Rarely, certain viral
illnesses cause an infection of the heart muscle known as acute myocarditis,
which produces temporary, but potentially life-threatening, heart failure. Long
term use of anabolic steroids (testosterone shots and similar male hormones
abused by athletes and others trying to build muscle mass) are dangerous in
many ways, among them is the increased risk for heart failure.
Heart Failure Caused by Corrective Mechanism
High blood pressure and the failing heart itself trigger a number of hormonal
and neurochemical mechanisms to correct imbalances in pressure and blood
flow. Unfortunately, while these corrective responses help in the short term,
they increase the work of the heart and can do considerable damage over the
long term. The brain responds to the failing heart pump by stimulating stress
hormones, in particular a powerful one called norepinephrine (commonly called
adrenaline). These hormones flood the heart, causing it to beat faster. The
heart also responds to overload by enlarging to increase the amount of blood,
which leads to structural damage called ventricular remodeling. The muscular
walls of this dilated heart become thinner and inefficient, and the faster
heartbeat accelerates the damage. As the volume of blood pumped to the
kidneys falls, the kidneys respond by retaining water and salt, which, in turn,
increases the edema in the body. To make matters worse, the body's arteries
respond to a lower blood volume by constricting, thereby forcing the heart to
work even harder to pump blood through these narrowed vessels, thereby
increasing blood pressure. Of special interest to researchers is endothelin, a
powerful protein involved in blood vessel constriction, which is produced in high
levels in congestive heart failure patients. Promising studies are reporting that
drugs blocking endothelin are improving survival in animals with heart failure.
Studies also indicate that the failing heart may damage itself further by
producing high levels of TNF-alpha, an immune factor known as a cytokine,
which is released by the immune system when tissues, including heart muscle
tissues, are injured. High levels of TNF-alpha are known to cause fatigue,
weight loss, shortness of breath, and weak pumping action, and experts now
believe that high levels of the substance produced by heart cells can actually
impair the heart's structure.
Symptoms of Congestive Heart Failure
Many symptoms of heart failure result from the congestion that develops as
fluid backs up into the lungs and leaks into the tissues. Other symptoms result
from inadequate delivery of oxygen-rich blood to the body's tissues. Since
heart failure can progress rapidly, it is essential to consult a physician
immediately if any of the following symptoms are detected.
Symptoms of Left-Side Heart Failure
In left-side heart failure, the more common condition, the first symptoms are
usually fatigue and shortness of breath (dyspnea) caused by fluid in the lungs.
Patients typically report that they feel out of breath after mild exertion. (This is
unlike the breathlessness of angina, which feels like a heavy weight pressing
on the chest.) An asthma-like wheezing is another common symptom. Patients
may also complain of a dry hacking cough that occurs a few hours after lying
down but then stops after the patient sits up. Over time, patients lose muscle
weight due to low cardiac output. Central sleep apnea, in which the brain fails
to signal the muscles to breathe during sleep, is a common condition associated
with heart failure. Sleep apnea causes disordered breathing at night. If heart
failure progresses, the apnea may be so acute that the sufferer, unable to
breathe, may awaken from sleep in panic.
Ultimately, fluid in the lung (pulmonary edema) may develop. When this
happens, in addition to dyspnea, patients sometimes have a cough that
produces a pinkish froth. Patients may experience a bubbling sensation in the
lungs and feel as if they are drowning. Typically, the skin is clammy and pale,
sometimes nearly blue. This is a life-threatening situation and the patient must
go immediately to an emergency room.
Symptoms of Right-Side Heart Failure
As with left-side heart failure, an early symptom of right-sided failure is
fatigue. Right-side failure leads to the accumulation of fluid, first in the feet,
next in the ankles and legs, and finally in the abdomen. The liver may also be
enlarged. Although their appetites are often depressed, patients with
congestive heart failure gain weight because they retain salt and water. At the
same time, patients gradually loses muscle mass as the tissues become oxygen
depleted.
Heart failure is the most common reason for hospitalization in the elderly.
Nearly five million Americans now suffer from heart failure, and as the
population ages the incidence of congestive heart failure is rising dramatically.
Estimated annual diagnosed cases rose from 250,000 people in 1970 to nearly
700,000 in 1992. Men are at higher risk than women, although the difference
narrows with age. The cause of heart failure in men is more likely to be
coronary artery disease; in women heart failure is more apt to be the result of
high blood pressure or unknown causes. African Americans are at higher risk
for the disease than white Americans and are two and a half times more likely
to die from it before age 65. It is most dangerous in African American women.
African Americans have a higher rate of high blood pressure and diabetes, two
major risk factors for congestive heart failure, but the difference can also be
accounted for by disparities in the care received by each group. A family
history of early congestive heart failure caused by cardiomyopathies may
predispose people to the disease. Other conditions that make one susceptible to
coronary artery disease and therefore congestive heart disease are smoking
and sedentary living. Alcohol abuse, which damages the heart, also predisposes
a person to heart failure. People with any long term disease that places stress
on the heart or circulatory system are at risk for heart disease. Survivors of
early childhood cancers have a risk for developing congestive heart failure in
later years. In one study, this complication was more common in women and
when high rates of the drug doxorubicin had been administered during
chemotherapy. Relatives of people with dilated cardiomyopathy have a
significantly increased risk for heart failure, with almost 30% of family
members showing some heart abnormality in one study.
About 250,000 people die of heart failure each year. For people over 65, it is
the number one cause of death. About 80% of patients with congestive heart
failure survive the first three months after diagnosis; about two-thirds survive a
year afterward. Those that survive appear to function well. Women whose
heart failure is caused by valvular heart disease, high blood pressure, or alcohol
abuse have a better survival rate than men with similar conditions. Their
survival rate, however, is equal to men when heart failure is caused by
coronary artery disease or heart attack. One important indicator of a poor
outlook is the development of cardiac cachexia, which is unintentional rapid
weight loss (a loss of at least 7.5% of normal weight within six months). About
half of the patients who die do so because of arrhythmias (irregular beating of
the heart) that often accompany heart failure. Death can also be caused by
acute pulmonary edema (fluid in the lungs). The discouraging mortality rates
are now being questioned by many experts who cite increasing success with
new treatments, the results of which have not yet appeared in studies of people
who currently have heart failure.
Classification of Severity
A classification system was developed by the New York Heart Association to
grade congestive heart failure by severity of symptoms. These classifications
help physicians determine treatment options.
- Class I: No limitation of physical activity. No shortness of breath,
fatigue, or heart palpitations with ordinary physical activity.
- Class II: Slight limitation of physical activity. Shortness of breath,
fatigue, or heart palpitations with ordinary physical activity, but
patients are comfortable at rest.
- Class III: Marked limitation of activity. Shortness of breath,
fatigue, or heart palpitations with less than ordinary physical
activity, but patients are comfortable at rest.
- Class IV: Severe to complete limitation of activity. Shortness of
breath, fatigue, or heart palpitations with any physical exertion
and symptoms appear even at rest.
It is important to note however that this method of classification is limited.
Symptoms may not relate to the actual severity of the condition. One study
found that half of heart failure patients who complained of breathlessness after
exercise had only mild heart abnormalities. On the other hand, some patients
do not report fatigue or shortness of breath after physical activity and yet they
may have severe heart damage. Experts suggest that physicians be sure to
consider other factors, including obesity, medications, and depression when
assessing a patient.
Prevention of Conditions Leading to Heart Failure
Prevention of heart failure relies principally on preventing or slowing the
progression of diseases that damage the heart, especially coronary artery
disease, hypertension, and diabetes. Everyone should always seek a lifestyle
that includes regular exercise, a diet low in saturated fat, cholesterol, and salt
and, at the same time, avoid smoking, alcohol abuse, obesity, and excessive
mental stress. Medications may be needed for those who have hypertension,
high cholesterol levels, or diabetes.
Prevention after a Heart Attack
Use of a drug known as an angiotensin-converting enzyme (ACE) inhibitor has
been shown to significantly reduce the risk of progression to congestive heart
failure in heart attack patients. Now studies are finding that combining a drug
known as a beta blocker with the ACE inhibitor is even more protective. [For a
discussion of these drugs, see below].
What Other Diseases Show the Same Symptoms as
Congestive Heart Failure?
A number of other conditions may produce symptoms suggestive of heart
failure. Shortness of breath is seen in asthma, certain allergic reactions,
near-drowning, pneumonia, inhalation of toxic substances or smoke, high
altitude sickness, and emphysema. Some patients with angina may interpret the
chest tightness associated with this syndrome as shortness of breath. Swollen
ankles can result from varicose veins or phlebitis. Liver or kidney failure also
causes fluid retention.
Physicians can often make a clinical diagnosis of heart failure with a medical
history and careful physical examination, checking particularly for enlargement
of the heart, irregular heart sounds, abnormal sounds in the lungs, swelling or
tenderness of the liver, fluid retention, and elevation of pressure in the veins of
the neck. Often, it is difficult to confirm a diagnosis of heart failure or
determine its severity once a diagnosis has been made, and further tests are
usually needed.
Laboratory Tests
Blood and urine tests are used to check for malfunctions of the liver and
kidneys. Blood tests can also be used to evaluate cholesterol and blood sugar
levels and to check for anemia and thyroid disease. A blood test that measures
concentrations of substances called natriuretic peptides, which are produced
when pressures or volumes within the heart increase, may prove to be
effective in screening and even diagnosing patients with possible congestive
heart failure. Of particular importance is one called B-type natriuretic peptic
(BNP). After a diagnosis of congestive heart failure is established, simple
blood tests that measure lymphocyte counts may prove helpful in predicting the
outcome. Lymphocytes are important infection-fighting white blood cells, and
low numbers reflect high levels of stress hormones, which increase the risk of
heart malfunction. In one study, patients with normal to high lymphocyte counts
had a four-year survival rate of 78% compared to 34% in patients with lower
counts.
Electrocardiogram
An electrocardiogram (ECG) is a simple test, often conducted in the
physician's office. Electrical leads are placed at several locations on the
patient's chest and limbs. Although an ECG cannot diagnose heart failure, the
test is inexpensive and useful in many ways. It can indicate underlying heart
disease by suggesting enlargement of the heart muscle (cardiomyopathy),
coronary artery disease, or abnormal cardiac rhythms. One study reported that
it may be effective in screening out patients who do not need a more accurate
(but more expensive) echocardiogram for a definite diagnosis. Another study
indicated that a certain type of rhythm pattern seen on an ECG, called a
prolonged QT interval, might predict those at risk for sudden death from
congestive heart failure and could be used for determining more intensive
treatment.
Exercise Stress Test
Measuring heart rate, blood pressure, and oxygen consumption while a patient
is exercising appears to be a more accurate method for determining the degree
of heart impairment than taking such measurements while the patient is at rest.
Imaging Techniques
X-rays, particularly an X-ray procedure known as radionuclide
ventriculography, can reveal cardiac enlargement or evidence of fluid
accumulation around the heart and lungs. X-rays are helpful both to diagnose
congestive heart failure and to confirm the effectiveness of treatment.
Echocardiography is a noninvasive, entirely safe test, which uses ultrasound to
image the heart as it is beating. Cardiac ultrasounds provide accurate
indications of valve function and the flow of blood through the heart's
chambers. They are extremely valuable in patients with congestive heart
failure, because they can reveal whether the failure is on the left, the right side,
or both. Echocardiograms also indicate the ejection fraction, the percent of the
blood pumped out during each heart beat. Echocardiography may also be
useful for early detection of potential heart failure in people who have not had
a heart attack; those identified as at risk using this method have a dilated left
ventricle, even if their hearts are still able to contract normally.
Angiography
Physicians may recommend angiography if they suspect that blockage of the
arteries is contributing to heart failure. During this procedure a thin tube, or
catheter, is inserted into one of the large arteries in the arm or leg and then
gently guided through the artery until it reaches the heart. The catheter
measures internal blood pressure at various locations, giving the physician a
comprehensive picture of the extent and nature of the heart failure. When dye
is injected through the tube into the heart, x-rays can be taken to depict the
dye's movement through the heart and arteries. These images, known as
angiograms, help locate problems in the heart's pumping action or blockage in
the arteries. Major complications of angiography include stroke, heart attacks,
and kidney damage, but these risks are very low (about 0.1%) if the procedure
is done in a center that performs it at least six times a week.
Drug Treatments for Congestive Heart Failure
The primary conditions causing heart failure should be treated first, including
coronary artery disease, valvular abnormalities, high blood pressure,
arrhythmias, anemia, and thyroid dysfunction. If heart failure persists after
treating underlying causes, drug treatments and life-style changes are generally
designed to achieve three goals: increasing the strength of the heart's
contraction; reducing the work of the heart; and reducing salt and water
retention. This is accomplished through drug therapy, rest, and dietary salt
restriction.
Three classes of medications have been the standard treatments for heart
failure: vasodilators (drugs that dilate blood vessels); inotropics (drugs that
increase the heart's ability to contract); and diuretics (drugs to reduce fluid).
One drug from a fourth class, beta blockers, has recently been added to the
armament. The specific medication or, more commonly, a combination of these
medications, is determined by the type and severity of the heart failure.
ACE Inhibitors and Other Vasodilators
Vasodilators improve both the quality and duration of life for heart failure
patients. They open the arteries and veins, thereby reducing the heart's
workload and allowing more blood to reach the tissues. Vasodilators are
particularly useful in treating heart failure associated with high blood pressure
and dilated cardiomyopathy. Several classes of vasodilators are available, the
most effective being the ACE inhibitors.
Angiotensin-Converting Enzyme (ACE) Inhibitors. Currently the most
important vasodilators are angiotensin-converting enzyme (ACE) inhibitors;
these drugs block the formation of angiotensin II, a powerful enzyme that
raises blood pressure, constricts blood vessels, and leads to salt retention.
Although experts believe that at least 50% to 75% of patients with congestive
heart failure should be treated with ACE inhibitors, a current study indicates
that primary care doctors are only prescribing them for 22% and specialists for
46% of patients. Women and nonwhites are even less likely to get ACE
inhibitors than white males. Even worse, about 15% of patients are being
prescribed expensive calcium channel blockers, which may even have adverse
effects for patients with heart failure. ACE inhibitors are of particular benefit
for patients with left ventricular systolic dysfunction; those patients should take
drugs indefinitely unless specific conditions make the drugs inappropriate.
Some cardiologists are concerned that ACE inhibitors are still not being
prescribed by their family physicians for many patients who might benefit from
them. Commonly used ACE inhibitors are captopril (Capoten), quinipril
(Accupril), enalapril (Vasotec), and lisinopril (Prinivil, Zestril). Captopril, which
has the most predictable onset and shortest duration, is most often used for
initial therapy when patients must be cautiously monitored for low blood
pressure. Enalapril has been found to improve survival over combinations of
other types of vasodilators (hydralazine and nitrates), and some studies have
indicated that it might actually reduce heart damage by inhibiting the
remodeling process that can cause heart attacks after heart failure. Yet
another study found that high doses of lisinopril were more effective than low
doses and do not cause significantly more adverse effects. Experts say these
findings should apply to all ACE inhibitors. A persistent cough is a common
and irritating side effect. The primary adverse effect of ACE inhibitors is low
blood pressure, which can be severe in some patients, particularly when
therapy is first initiated. Because of this, ACE inhibitors have not been used for
patients who have pulmonary edema (fluid in the lungs), a condition commonly
accompanied by low blood pressure. One study found, however, that the drugs
may benefit even these patients, assuming that blood pressure is not
excessively low to begin with. Kidney failure is a rare complication that can
occur during initial therapy. Taking ACE inhibitors may also lead to excessive
potassium levels, and so they are not generally given with potassium-sparing
diuretics or potassium supplements. (Diuretics, in general, are often very
important for many heart failure patients, however, even those taking ACE
inhibitors.)
Hydralazine and Nitrates. The oral direct-acting vasodilators hydralazine
(Apresoline) and isosorbide dinitrate (Iso-Bed Isorbid) improve symptoms and
may prolong life when used in combination. Intravenous nitroglycerin
(Nitro-Bid Iv, Nitrostat IV, Tridil) and intravenous nitroprusside (Nitropress)
are useful in short-term therapy of acute heart failure and acute pulmonary
edema. Intravenous nitroglycerine tends to lose effectiveness quickly, but one
study showed that patients who were also given oral hydralazine continued to
tolerate this drug. Combinations of hydralazine with nitrates are more effective
than either drug used alone and are recommended when patients cannot
tolerate ACE inhibitors.
Angiotensin II Receptor Antagonists. Angiotensin II receptor antagonists
have benefits similar to ACE inhibitors and may have fewer or less severe side
effects, including coughing. They may also have positive effects on blood
vessels. Valsartan and losartan are being tested for congestive heart failure. In
studies comparing losartan to ACE inhibitors, losartan was as effective in
improving heart function and symptoms as the ACE inhibitors enalapril and
captopril, but it is not yet known if these newer drugs will have the same
benefits on long-term survival.
Calcium-Channel Blockers. Calcium channel blockers are vasodilators
commonly used for high blood pressure and angina, but standard calcium
channel blockers worsen heart failure and so these drugs should not be used
under most circumstances. Recent studies have also been reporting a number
of other adverse effect. A recent study found, for example, that people with
type 2 diabetes who were treated with a long-acting calcium channel blockers
had a significantly higher risk for heart attacks than those taking an ACE
inhibitor. Unfortunately, they are currently over-prescribed for patients with
heart failure. A newer generation calcium-channel blocker, amlodipine
(Norvasc), may reduce death rates in a small subgroup of heart failure patients
who have idiopathic dilated cardiomyopathy without coronary artery disease.
Inotropic Drugs and Digitalis
Digitalis. Until recently, the inotropic drug digitalis was the first-line therapy
for heart failure. Digitalis increases the strength of the heart's contractions,
reduces heart size, and reduces certain arrhythmias. Derived from the
foxglove plant, it has been used to treat heart disease since the 1700s and is
still the only oral inotropic agent in general use. Controversy has been on-going
for more than 100 years over whether the benefits of digitalis outweigh its risks
and adverse effects. In general, digitalis does not reduce mortality rates,
although it improves symptoms; patients who take digitalis are also hospitalized
slightly less often than those not taking the drug. Many experts now believe
that patients should first be prescribed drugs proven to prolong life, such as an
ACE inhibitor or the beta blocker carvedilol, before digitalis is recommended.
Digitalis may be useful for patients with systolic dysfunction characterized by
low ejection fractions and is helpful in heart failure patients with atrial
fibrillation, a type of rapid, irregular heart beat. Digitalis may even be harmful
in some patients with heart failure, particularly when caused by diastolic
dysfunction characterized by normal to high ejection fraction.
Although several digitalis preparations are available, most physicians today
prescribe digoxin (Lanoxin). While digitalis is generally a safe drug, it can have
toxic side effects caused by overdose or other accompanying conditions. The
most serious side effects are arrhythmias, abnormal heart rhythms that can be
life-threatening. Factors which increase the risk of toxicity include advanced
age, low blood potassium levels (which can be caused by diuretics),
hypothyroidism, anemia, valvular heart disease, and impaired kidney function.
Digitalis interacts with many other drugs, including, but not limited to, quinidine,
amiodarone, verapamil, flecainide, amiloride and propafenone. Patients should
be sure to tell the physician about all of their other medications. Early signs of
toxicity may be irregular heart beat, nausea and vomiting, stomach pain,
fatigue, visual disturbances (e.g., yellow vision, seeing halos around lights,
which may also flicker or flash), and emotional and mental disturbances. Some
of these side effects may also be mild and not harmful. Toxic side effects used
to be experienced by nearly 25% of patients taking digitalis, but now that a
blood test can be used to monitor the level of the drug in the blood, toxicity is
down to 2%. In any case, a recent study reported that for most patients with
mild to moderate heart failure low-dose digoxin may be as effective as higher
doses. If side effects exist, but are mild, patients should still consider continuing
with digitalis if other benefits are experienced. It was found that patients who
stopped taking digoxin after using it in combination with ACE inhibitors were at
risk for worsening heart failure.
Other Inotropic Drugs. There was a surge of interest in other oral inotropic
agents, including vesnarinone, milrinone, flosequinan, and amrinone. Large
studies of these agents, however, were disappointing and some even reported
increased mortality rates.
Diuretics
Diuretics have long been used to relieve fluid retention, a hallmark of
congestive heart failure and aggressive use of diuretics, even in people taking
ACE inhibitors, can reduce hospitalizations and improve exercise capacity.
Diuretics act on the kidneys to rid the body of excess salt and water. They
reduce the accumulation of fluid in the legs, abdomen, and lungs, lower blood
pressure, and improve the efficiency of the circulation. Side effects of diuretics
include low blood pressure, dehydration, and kidney dysfunction; they also may
trigger gout, increase blood sugar and triglyceride, LDL, and overall cholesterol
levels, and may deplete the B vitamin thiamin. Although many diuretics are
available, they are generally categorized as thiazides and loop diuretics, used
with or without potassium-sparing agents. It is important to note that a recent
study found an increased incidence of hospitalization in patients who were
taking nonsteroidal anti-inflammatory drugs (NSAIDs) along with diuretics.
Common NSAIDs include aspirin, ibuprofen (Advil), and naproxen, among
many others.
Thiazides. Thiazides, including hydrochlorothiazide (HydroDiuril, Esidrex),
chlorthiazide (Diuril), metolazone (Zaroxolyn), and chlorthalidone (Hygroton),
are usually prescribed for patients with mild heart failure and good kidney
functioning.
Loop Diuretics. Loop diuretics, such as furosemide (Lasix), bumetanide
(Bumex), and ethacrynic acid (Edecrin), are generally used for more severe
heart failure, especially when kidney function is impaired. Loop diuretics are
used intravenously to treat pulmonary edema and acute congestive heart
failure; a thiazide and a loop diuretic may be administered simultaneously. Fluid
may persist in the lungs even after standard treatment for congestive failure,
limiting the patient's ability to function normally. One study treated patients
with this condition very aggressively with furosemide to further reduce fluids,
but no improvement was seen. Another method using a filtration technique was
more successful.
Potassium-Sparing Agents. Potassium loss is a major problem with diuretic
use. Unless patients are also taking ACE inhibitors, which raise potassium
levels, the physician may recommend a potassium supplement or the use of a
potassium-sparing diuretic, such as spironolactone (Aldactone), amiloride
(Midamor), and triamterene (Dyrenium), along with a thiazide or loop diuretic.
All patients receiving diuretics with or without potassium-sparing drugs should
have their blood potassium levels checked at regular intervals.
Beta Blockers
Beta blockers prevent norepinephrine (adrenaline) from binding to heart cells,
which affects the frequency and force of heart beats. Because these drugs
reduce the pumping action of the heart in the short term, they were not
normally used for treatment of heart failure. Elevated levels of norepinephrine,
however, are also associated with severe heart failure and many studies have
now shown that carvedilol (Coreg), an atypical mild beta blocker with some
vasodilating properties, has important benefits for many patients. Combinations
of this beta blocker with other heart failure medications can improve heart
function and size and reduce mortality rates in patients with mild to severe
heart failure. Its positive effect on symptoms, including the ability to perform
physical exercise, however, is not as apparent. Although it appears to be
effective for heart failure from nearly any cause, the drug may be more useful
for certain people, including those with dilated cardiomyopathy, and patients
with fast heart rates (faster than 82 beats per minute). Carvedilol must be
monitored and the dosages regulated very carefully, however, since heart
failure may actually worsen in the early stages of treatment. It should not be
used in people with asthma, those with very slow heart beats (bradycardia),
patients on intravenous inotropics, or people with certain heart conduction
disorders. Bucindolol is a similar beta blocker under investigation. Other, older
beta blockers being studied for heart failure include metoprolol (Lopressor) and
labetalol (Normodyne, Trandate). One recent study found that beta blockers in
general--not just carvedilol--reduced mortality rate in heart failure patients by
over 30%. Experts warn however that because of the increased dangers
during early treatment, the wide-spread use of beta blockers for heart failure
warrants caution and these drugs, including carvedilol, should be administered
only by specialists experienced in treating heart failure.
Anti-Clotting Drugs
Two studies have reported that heart failure patients taking drugs that prevent
blood clots, including warfarin (Coumadin), aspirin, or dipyridamole
(Persantine) significantly reduced the risk of death. Both studies were
primarily investigating the ACE inhibitor enalapril, and in one of the studies,
patients who took enalapril along with aspirin or dipyridamole did slightly less
well than those taking the anti-clotting drugs alone (but still did better than
patients who were taking none of these drugs). Experts warn, however, that
until more studies are done, anti-clotting drugs should be used with caution in
heart failure patients unless they have atrial fibrillation, previous
thromboembolism, or other risk factors for blood clots.
Drugs for Arrhythmias
Drugs used to treat irregular heart beats (arrhythmias), which are a particular
danger for congestive heart patients, have not been very successful in
prolonging survival when used as part of the treatment regimen for congestive
heart failure. Trials using low doses of the anti-arrhythmic drug amiodarone
(Cordarone) reported improved mortality rates in patients with severe heart
failure who also had elevated heart rates of more than 90 beats per minutes.
Not only was there a reduction in death rate, but the patients' ability to function
was also improved. Another study found that a combination of amiodarone and
hydralazine improved survival in women with atrial fibrillation, a condition
marked by rapid twitching of the heart walls. The drug apparently has no
benefit for those with slower heart rates.
Other Drugs for Relief of Symptoms
Ipratropium (Atrovent), a drug normally used by asthma patients, was tested in
a small study of smokers and nonsmokers with congestive heart failure for
improving lung function. Breathing improved in all patients who were
administered four puffs of the drug using an inhaler. The drug has no known
adverse effects on the heart, and there were no other side effects in this
group. More studies are needed.
Theophylline, an asthma drug, was found to improve oxygen levels and lung
function in heart failure patients who also experienced central sleep apnea, the
disordered breathing syndrome associated with left-side heart failure.
Experimental Drugs
Experimental drugs that include pentoxifylline and TNFR:Fe block tumor
necrosis factor (TNF). TNF is produced by the immune system and causes
inflammation, dilation, and other abnormalities in the heart and may be a
leading factor in the development of heart failure. Pentoxifylline is showing
promise in reversing symptoms of heart failure in human trials and TNFR:Fe
has reversed symptoms in animal studies. One promising study reported that
patients with recent-onset dilated cardiomyopathy who were given intravenous
immune globulin while waiting for transplantation experienced improved
function to the point that nearly all were removed from the transplant list.
Drugs that inhibit parts of the nervous system or hormonal pathways that lead
to heart failure are also being investigated. A unique drug, BNP, whose
vasodilating properties decrease pressure in the heart and increase pumping
strength, is showing promise in trials. A cold virus is being used to deliver to
the heart genes of a calcium-transporting enzyme, called adenosine
triphosphatase, or ATPase; theoretically, by supplying calcium to heart
muscles, the enzyme could strengthen their contractions. Neither animal nor
human studies have been conducted and the use of such a drug, if feasible, is
years away.
Surgical Treatments for Congestive Heart Failure
While drug therapy is the most common approach to heart failure, certain
patients may require surgical interventions. Patients with severe coronary
artery disease may benefit from angioplasty or bypass surgery. Patients with
faulty heart valves can have artificial valve replacement surgery.
Heart Transplantation
Class III and IV patients who suffer from severe heart failure and whose
symptoms do not improve with drug therapy may be candidates for heart
transplantation. Traditionally transplants have been performed only on patients
under 60, but studies indicate that selected older patients can benefit from this
procedure and one study found that older transplant patients achieved a better
quality of life than younger patients. While the risks of this procedure are high,
the two-year survival rate is about 78% and after five years it ranges from
50% to over 70%. About 76% of transplant patients are male and 85.4% are
white. In general, the highest risk factors for death three or more years after a
transplant operation are coronary artery disease and the adverse effects
(infection and certain cancers) of immunosuppressive drugs used in the
procedure. Older patients are at particular risk for cancers from these drugs
and for osteoporosis, but their rejection rates appear to be similar to those of
younger patients.
Alternatives to or Holding Measures until Transplantation
In any one month, about 4,000 people are registered for a heart transplant
procedure, although only about an average of 166 transplants are performed
each month. A number of procedures are now available for patients who are
waiting for transplantations; some may even offer permanent alternatives.
Studies indicate that most patients in stable condition can be managed safely
with medications for many months while waiting for a transplant. Portable
pumps that continuously infuse medications such as dopamine and
prostaglandin E-1 can allow the patient to remain mobile and active. Other
procedures may also be performed to help maintain heart function.
Left Ventricular Assist Device (LVAD). In those whose heart beat has slowed dangerously (a condition known as bradycardia), a left ventricular
assist device (LVAD) may be implanted in the chest to increase the pumping
action of the heart. Until recently, LVAD required a large, hospital-based
immobile console to which the patient was attached while waiting for a
transplant. Miniaturized battery-powered LVAD units, however, may allow
many patients to leave the hospital and even resume normal activities, such as
work, golf, and sexual activity. Eventually these smaller devices may even
provide a permanent solution for some patients who are not candidates for
transplantation. There are risks, however, involved with LVADs, including
bleeding, blood clots, and right heart failure.
Ventricular Remodeling. Ventricular remodeling (also called partial left ventriculectomy or the Batista procedure, after its inventor) may allow some
patients with dilated cardiomyopathy to avoid a heart transplant. The procedure
involves first removing a section of healthy heart muscle weighing about three
ounces. The surgeon then reshapes the heart to a more normal size and form
and repairs any faulty heart valves. The procedure is effective in about 75% of
cases; unfortunately, if it fails, the patient must have an immediate heart
transplant. The procedure is not used for people whose heart failure developed
from coronary artery disease or after a heart attack. Ventricular remodeling is
a new procedure and not yet widely available; early trials in the U.S. have
reported positive results and improvement has been sustained in the Brazilian
patients whose hypertrophy resulted from valvular or viral disease. In cases
where the muscle itself was diseased, the hearts have begun to redilate. Even
in such cases, however, the procedure can be repeated.
Dynamic Cardiomyoplasty. Dynamic cardiomyoplasty is useful in carefully selected patients with congestive heart failure. The procedure detaches one
end of a muscle from the back and wraps it around the ventricles of the heart.
After a few weeks, these relocated muscles are conditioned with electrical
stimulation to behave and beat as if they were heart muscles. The procedure
benefits the failing heart in many ways, including improving systolic pressure,
limiting dilation of the heart, and reducing heart muscle stress. Oddly, the
procedure seems to improve symptoms significantly although it has only a
modest effect on actual blood circulation. One long-term study reported that
heart muscle structure was preserved in 84% of patients. Survival rates were
estimated to average 54% after seven years, but they may be higher or lower
depending on individual characteristics. The procedure does not preclude a
later transplant operation.
Intra-aortic Balloon Pump. The intra-aortic balloon pump (IABP) is a device that is helpful for maintaining heart function for people waiting for transplants.
Usually, it is used only for short periods, but recent studies indicate that
patients may be able to use it safely for somewhat longer periods (an average
duration of 23 days in one study).
Lifestyle Recommendations for Congestive Heart Failure
Between 30% to 47% of patients who require hospitalization for heart failure
are back in the hospital again within six months. Many people return because
of life-style factors, such as poor diet, failure to comply with medications, and
social isolation.
Home Support and Rehabilitation Programs
In one study, elderly people who had no emotional support at home had triple
the risk of a heart attack after hospitalization for heart failure than those who
did have such support. (In women, this risk was eightfold.) In yet another
study, the greatest risk factor for death and readmission to the hospital after a
first hospitalization for heart failure was being single regardless of the health of
the patient at discharge. In a number of studies, programs that offer intensive
follow-up to ensure that the patient complies with lifestyle changes and
medication regimens at home are reducing rehospitalization and costs and
improving survival. Patients without available rehabilitation programs should
seek support from local and national heart associations and groups.
Diet and Weight
Heart failure patients should weigh themselves each morning and keep a
record. A sudden increase in weight of more than two or three pounds may
indicate fluid accumulation and should prompt an immediate call to the
physician. Rapid wasting weight loss over a few months is a very serious sign
and may indicate the need for surgical intervention. All heart failure patients
should limit their salt intake, and in severe cases, very stringent salt restriction
may be necessary. Patients should not add salt to their cooking and their
meals. They should also avoid foods high in sodium; these include ham, bacon,
hot dogs, lunch meats, prepared snack foods, dry cereal, cheese, canned soups,
soy sauce, and condiments. Some patients may need to reduce their water
intake as well. People with high cholesterol levels or diabetes require additional
dietary precautions. One study indicated that foods high in nutrients called
flavonoids may have some benefit; such foods include tea, apples, onions, and
red wine. In any case, a diet low in saturated fats and high in fiber, fresh fruits
and vegetables is always recommended. A small study reported that taking
capsules L-arginine, found in health food stores, may have some benefit. This
amino acid appears to reduce endothelin, a protein that cause blood vessel
constriction and is found in high amounts in heart failure patients. It is
important to stress that no supplement or diet can cure heart failure.
Rest and Exercise
Traditionally, heart failure patients have been discouraged from exercising.
Now, exercise is proving to be helpful for many patients and, when performed
under medical supervision, does not pose a risk for a heart attack. In one study,
patients between the ages of 61 and 91 increased their oxygen consumption by
20% after six months by engaging in supervised treadmill and
stationary-bicycle exercises. People not used to exercising should start with
five to 15 minutes of easy exercise with frequent breaks. Although the goal
would be to build to 30 to 45 minutes of walking, swimming, or low-impact
aerobic exercises three to five times every week, any amount of time spent
exercising is useful, assuming that the physician has approved the exercise
program. One study found that performing daily hand grip exercises improved
blood flow through the arteries of patients with heart failure. This was backed
up by a more recent study that suggested that the loss of strength in small
muscles, such as those in the hand, may produce as much exercise intolerance
as heart failure itself.
Bed rest may be required in cases of severe congestive heart failure. To
reduce congestion in the lungs, the patient's upper body should be elevated; for
most patients, resting in an armchair is better than lying in bed. Relaxing and
contracting leg muscles is important to prevent clots. As the patient improves,
progressively more activity will be recommended.
Warm Baths and Saunas
Experts have traditionally recommended that people with heart failure avoid
warm baths, which can increase the heart rate. Now, one study has reported
that carefully controlled bathing for short periods may not be harmful and, in
fact, may be beneficial, increasing cardiac output and ejection fraction. Warm
water may behave like a vasodilating drug, opening up the vessels gently and
improving circulation. The people in the study sat in water up to their chests at
106 F or in a dry sauna at 140 F. In both situations they sat for 10 minutes
with their torsos tilted at 45 degrees. None of them experienced pain in the
heart, shortness of breath, or irregular heart beats. Prolonged periods in hot or
even warm conditions can be dangerous, however. Any patient with heart
failure should consult the physician first, not bathe unaccompanied, and be sure
that the temperature does not go above the ones described in this report for
either water bathing or dry saunas.
Stress Reduction
Stress reduction techniques may have direct physical benefits lowering stress
hormones, including cortisol (which suppresses the immune system) and
norepinephrine (also known as adrenaline), the chemical messenger associated
with heart dysfunction. Many effective stress reduction techniques, including
meditation and relaxation methods, are available.