Click
here for Multimedia Lecture on Heart Failure!
What is Congestive Heart Failure
(CHF)?
How common
is CHF
How serious
is CHF
What are
the causes of CHF?
What
are the symptoms or complaints of CHF?
How
does the body respond to CHF?
What
is Diastolic heart failure?
How
is CHF diagnosed?
How is CHF treated?
How is CHF treated? The treatment of CHF is divided into the following
four parts:
- Prevention of initial cardiac injury:
Coronary artery disease and hypertension are the two
commonest causes of CHF. Dietary restrictions, exercise,
weight reduction in obese individuals, cessation of
smoking, and treatment of risk factors like a high
cholesterol level and diabetes are important cornerstones
in the prevention of CAD. Use of medications to control
blood pressure also goes a long way in preventing
CHF. Since heavy use of alcohol can contribute to
the development of CHF, such a tendency needs to be
discouraged.
- Prevention of further injury: Aggressive early treatment
of a heart attack reduces the amount of damaged muscle
and decreases the likelihood and severity of CHF.
- Prevention of post-injury deterioration: Studies
have shown that patients who have suffered considerable
muscle damage after a heart attack tend to do better
if they are maintained on a class of drugs known as
ACE inhibitors. It is believed that these medications
prevent further deterioration.
- General treatment of CHF.
Medications that are commonly used in the treatment
of CHF:
Diuretics
plus reduction of salt and fluid intake: All patients
with CHF benefit from moderate salt restriction with
daily measurement of weight. This permits the use of
lower and safer doses of diuretics or "water pills", which include furosamide (Lasix®).
torsemide (Demadex®), bumetanide (Bumex®), HCTZ (hydrochlorothiazide), etc.
As noted earlier, CHF results in retention of salt and
water. This causes an in increased body weight, swelling
and shortness of breath. Diuretics or "water pills"
are effective because they increase the excretion of
urine and sodium (which is contained in salt). There
are several different types of diuretics available.
Their selection is based upon the patient's kidney function
and severity of heart failure. At times, a combination
of two diuretics may be used . The goal of this form
of treatment is to eliminate symptoms and the physical
signs of fluid retention. Measurement of daily weight
is important in monitoring diuretic treatment. A steady
weight gain could indicate inadequate effects.
Patients need to remember that diuretics have a tendency
to increase thirst. The purpose of taking a diuretic
is defeated if one succumbs to thirst and drinks an
extra 1500 cc of fluids after taking taking a diuretic
and making the same amount of urine. Check with your
physician about the amount of fluids that you are allowed
per day. Then stick to that restriction. You need to
use a measuring cup to help determine your fluid intake,
or at least know the size of your drinking glass (i.e.,
6 ounces, etc.). Remember that fluids include water,
juice, coffee, tea, soda, milk, soups and any fluid
that is liquid at room temperature (popsicle, ice and
gelatin). Also, note that watermelon, when eaten in
large amounts, can result in the intake of a lot of
fluid.
Taking a diuretic can result in
the depletion of important electrolytes or minerals
like potassium. For this reason, the use of a diuretic
is frequently accompanied by the addition of a medication
that contains potassium. Alternatively, your physician
may combine a different type of diuretic ("potassium
sparing") which will help reduce the wasting of
potassium. Potassium sparing diuretics include Maxzide®, Dyazide®, Triamterene-HCTZ, spironololactone (Aldactone® and Aldactazide®), etc. Excessive use of diuretics can decrease the
volume of circulating blood. This in turn can result
in decreased blood pressure, weakness and worsening
kidney function. It is more likely to occur if one has
a reduced intake of fluids (loss of appetite, nausea,
etc.), or loose fluids due to diarrhea and vomiting.
Monitoring of your weight and periodic check of your
potassium level and kidney function helps to avoid this
problem.
While taking a diuretic, your physician
may advise you to eat foods that are rich in potassium.
Very good sources of potassium
include bananas, cantaloupe, honey dew melon, prunes,
grapefruit and oranges.
Good sources of potassium
are cooked dried beans, cooked greens, sweet potato,
green lima beans, white potato, winter squash, fruit
cocktail, raisins, apple juice and peaches.
Patients with CHF also need to limit
the intake of salt. Most of the sodium (component of
salt) comes from our salt shaker and from processed
food that include canned food, boxed mixes, and most
ready-to-eat foods in the grocery store. We also take
in sodium with salted nuts, fast foods, salad dressing,
buttermilk, soup, salt pork, bacon, cereals, vegetable
juice, cheese, pickles, cured meats, peanut butter,
snack foods, and sauces. A patient can significantly
improve the management of CHF by paying attention to
food labels.
ACE (angiotensin-converting
enzyme) Inhibitors: ACE inhibitors are an extremely
important in the treatment of CHF. They are almost always
employed, unless contraindicated or not tolerated by
the patient.
Remember that ACE is released in
a patient with CHF and is responsible for making certain
arteries constrict or clamp down. In the pump and balloon
example discussed previously (and shown above), ACE
is responsible for increasing blood flow to the brain
and other vital organs by constricting arteries and
reducing flow to the less essential skin and muscle
of the arm and legs. Unfortunately, this action increases
the resistance against which the heart has to contract.
This translates to extra work for
a heart that is already weak and failing. Ironically,
an action that was designed to help a heart with a reduced
output turns out to be harmful to the failing heart.
ACE inhibitor drugs blocks the ACE system and relax
the walls of the artery. This lowers pressure and the
resistance against which the failing heart has to pump
against and reduces the work that it has to perform.
Multiple research studies have shown that ACE inhibitors
, when used in patients with CHF, can improve symptoms,
decrease the need for emergency care, reduce the dosage
of diuretics, and lower the risk of death.
Examples of ACE Inhibitors include benazepril (Lotensin®), captopril (Capoten®), enalapril (Vasotec®), fosinopril (Monopril®), Lisnopril (Zestril® or Prinivil®), moxepril (Univasc®), perindopril (Aceon®), quinapril (Accupril®), ramipril (Altace®), trandolapril (Mavik®), etc. Many ACE Inhibitors are also marketed in combination with a diuretic (HCTZ).
The following is additionally noted
with ACE inhibitors:
- Side-effects may occur early but does not necessarily
prevent long-term use if the dosage of this drug and
other medications are adjusted.
- Significant improvement in symptoms may be delayed
for several months. So do not give up hope in the
early stages.
- ACE inhibitors reduce disease progression, even
when patients do not note a significant improvement
in symptoms.
Risks of treatment with ACE inhibitors
include decreased blood pressure, dizziness, worsening
kidney function, potassium retention, cough (in 5-15%
of cases), and an allergic reaction known as angioedema
(in less than 1% of cases) that can result in swelling
of the face and tongue with associated difficulty in
breathing.
Angiotensin-2
Receptor blockers or ARB: This class of drugs,
as a group, is relatively new, compared to ACE inhibitors, and are also used in the treatment of CHF, particularly when ACE inhibitors are not tolerated by the patient because of side-effects. Studies have demonstrated a
beneficial effect of ARBs in CHF, similar to that seen with
ACE inhibitors. Although differing in chemical structure
and its point of action, angiotensin-2 inhibitors dilate or open-up the arteries. This reduces the
workload of the failing heart, improves symptoms and
decreases the risk of death. The big advantage of this
class of drugs it is far less likely to produce cough
and angioedema. Available examples of ARBs include losartan (Cozaar®), valsartan (Diovan®), irbesartan (Avapro®), candesartan (Atacand®), telmisartan (Micardis®), eprosartan (Teventen®), olmesartan (Benicar®), etc. Like ACE inhibitors, several ARBs are also marketed in combination with a diuretic (HCTZ).
Carvedilol or Coreg®:
As the output of the heart drops in patients with CHF,
the body is stressed and releases catecholamines (pronounced
caty-chole-a-meens). They are also called adrenergic
(pronounced ad-ree-ner-jic) agents because they are
released by the adrenal gland (which sits on top of
the kidneys). Adrenaline is such an adrenergic substance. It increases
the heart rate and stimulates the weak heart muscle to contract
more forcefully. This is known as a "beta adrenergic
effect" and increases the work that the heart has
to perform. The sick heart gets tired and sicker as it works harder!
The adrenergic substances also cause
the arterial walls to constrict or tighten. This is
known as "alpha adrenergic effect" and helps
to raise the blood pressure when the weak heart cannot
do so on its own. However, as in the case of ACE activity,
this increases the resistance against which the weak
heart has to pump, putting an additional load on the
struggling heart.
Carvedilol is a fairly new class of
drugs that is being used in the treatment of CHF. The
drug blocks both the alpha and beta blocking effects
of the adrenergic substances produced by the body. The
heart rate is slowed, the weak heart muscle is protected
from the "whipping" or stimulating effects
(thus reducing the chance of further deterioration)
and the arteries are dilated so as to make it easier
for the heart to empty. All these actions, like those
of ACE inhibitors are CHF-friendly. Carvedilol, like
ACE inhibitors have been shown to improve symptoms,
decrease the need for hospitalization and improve survival
in patients with CHF.
Carvedilol and other agents in its
class are always considered in the treatment of CHF
unless they are contraindicated or not tolerated. They
are generally avoided in patients with asthma, extremely
slow heart rates and very low blood pressure.
Beta blockers: A beta blocker blocks the beta adrenergic effects of adrenaline and thus prevents the sick heart from b eing forced to work harder. This "conservation effort" has a protective effect. Unlike carvedilol, beta blockers do not block the alpha receptor and are thus usually considered to be less effective in the treatment of CHF. However, like carvedilol and
ACE inhibitors, beta blockers are generally expected to improve symptoms,
decrease the need for hospitalization and improve survival
in patients with CHF.
Beta blockers are usually selected because they are frequently less expensive than carvedilol. Also, certain beta blockers like metoprolol (Toprol XL® and Lopressor®) and bisoprolol (Zebeta®) are better tolerated than carvedilol in certain patients with lung disease. Similarly, beta blockers like pindolol (Visken®) and acebutolol (Sectral®) may be used in patients who tend to have a slower heart beat.
Hydralazine: Hydralazine is a drug that dilates arteries and thus reduces the work that the weak heart muscle performs in pumping blood through them. However, this drug is not shown to be generally beneficial as ACE inhibitors in prolonging the life of all patients with CHF. However, Bidil®, a combination of hydralazine and isosorbide (a long acting form of nitroglycerin) has been shown to benefit African American patients with CHF.
Digitalis or Digoxin:
Digoxin is recommended in the treatment of CHF that
is caused by a weakened heart muscle. It is used in
conjunction with other agents such as diuretics, ACE
inhibitors and adrenergic blockers like carvedilol.
Although it stimulates the weak heart muscle to contract
a little more vigorously, it is felt that the long term
beneficial effects of the drug may be related to the
indirect inhibition of adrenergic substance release.
Digitalis is also useful in treating
certain types of rapid heart beat (atrial fibrillation
and atrial flutter) that may accompany CHF.
Other
drugs and devices that may be used in the treatment of
CHF include spironolactone (Aldactone®, which has
been shown to preserve potassium and reduce the deterioration
of CHF), warfarin or Coumadin® or "blood thinners"
(that reduce the risk of blood clots), antiarrhythmic
agents (to treat dangerous irregular heart
beats), blood pressure medications
(when ACE inhibitors are unable to control the high
blood pressure, or is contraindicated). More recently, specialized Bi-V or bi-ventricular pacemakers may be recommended in select patients with CHF and a left bundle branch block. Also, an ICD (implantable cardioverter-defibrilator) or a Bi-V ICD may be considered in patients with CHF due to coronary artery disease and prior heart attacks.
This concludes the section on Heart failure. Please
note that that you may listen to a multimedia
lecture on heart failure, if you so desire by clicking
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