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Saturday, May 1, 2010

Congestive Heart Failure

* Definition of Congestive Heart Failure
* Description of Congestive Heart Failure
* Causes and Risk Factors of Congestive Heart Failure
* Symptoms of Congestive Heart Failure
* Diagnosis of Congestive Heart Failure
* Treatment of Congestive Heart Failure
* Questions To Ask Your Doctor About Congestive Heart Failure

Definition of Congestive Heart Failure
Article updated and reviewed by Neil Siecke, MD, Clinical Insturctor, UCSD Division of Cardiology on July 28, 2005.

Congestive heart failure (or heart failure) occurs when the heart is unable to pump enough blood (which provides oxygen) to the muscles, tissues, and other organs of the body.

Statistics on Heart Failure

* A person aged 40 years or older has a one in five chance of developing heart failure.

* About five million Americans have been diagnosed with heart failure.

* About 550,000 new cases are diagnosed each year.

* Heart failure is the most common hospital discharge diagnosis with more than one million hospital stays each year.

* The costs of treating heart failure in the United States exceed $27 billion.

* The risk of heart failure increase with age: 10% of both men and women over 75 have been diagnosed with heart failure.

Statistics derived from the American Heart Association, Heart Disease and Stroke Statistics — 2005 Update

Description of Congestive Heart Failure
There are three ways that the pumping ability of the heart can be affected:

1. The mechanical pump can be ineffective, reducing the ability of the heart to move blood forward.

2. The valves that allow blood to go forward and prevent it from going backwards can fail.

3. The electrical controls for the pump can fail.

Problems with the Pump

Problems with the pumping functions of the heart are the most common cause of heart failure. The heart is actually made up of two pumps, one which pumps blood to the lung (the right heart) and the other which pumps blood to the rest of the body (the left heart). The left heart is usually stronger and is also more likely to fail.

The heart can fail for one of two reasons. If it is weak, it can not expel the appropriate amount of blood with each heart beat. It will try to compensate by beating faster, but there are limits to this. How much blood is expelled with each beat is called the ejection fraction (EF). Normally the heart expels about 50% of the blood in chamber with each beat; however, when the heart is weak, this number can fall to 30% or even lower. Symptoms typically begin when the EF falls to around 40%. This type of failure is known as systolic dysfunction.

The other type of heart failure is called diastolic dysfunction. With diastolic dysfunction, the EF is normal. The problem is that the heart does not fill appropriately. It becomes too stiff and can not enlarge fast enough to accept the appropriate amount of blood into the chamber before contracting to move the blood forward. Because the heart is not filling fast enough, blood backs up behind the heart in the lungs.

The right heart can also fail. The right heart is designed to pump against low pressure, as the blood pressure in the lungs is usually < 40 mmHg. If this pressure becomes elevated, the pump is unable to push the blood forward and it will collect in the veins of the legs and abdomen. The most common cause for high blood pressure in the lungs is backing-up from left heart failure, but other causes such as pulmonary hypertension, blood clots in the lungs, and severe emphysema can also raise this pressure.

Causes for Systolic Dysfunction (Weak Hearts:

* A previous heart attack is the most common cause for a weak heart; the muscle tissue in this area dies and is replaced by scar tissue which has no pumping activity; just having multiple areas of blocked arteries can also weaken the heart

* Certain kinds of viral infections can attack the heart muscle

* Alcohol abuse

* Illicit drugs such as methamphetamine and cocaine

* Certain, mostly older, chemotherapy drugs

* Some auto-immune disorders

* Rarely the heart weakens after pregnancy, known as post-partum cardiomyopathy

Causes for Diastolic Dysfunction (Stiff Hearts):

* High blood pressure for many years is the most common cause of a stiff hear; a blood pressure greater than 160/90 mmHg doubles the risk of a person with a blood pressure of 140/80

* Diabetes seems to worsen the effects of high blood pressure

* Hypertrophic Cardiomyopathy (a group of genetic abnormalities that results in thickened hearts)

* Infiltrative diseases such as amyloidosis

* Some valvular problems also cause the heart to become stiff

* Certain diseases of the pericardium, or lining, around the heart

Problems with the Valves

The heart has four valves that allow the blood to move forward and prevent it from going backwards. The valves can fail either because they become clogged and do not allow blood to move forward easily, or they can become leaky in which case too much blood flows backward, and not enough moves forward.

Most valve problems will result in a murmur. The murmur may begin many years before the problem becomes noticeable, but this is not always the case.

Reasons that the valves can fail include the following:

* Congenital (birth) defects

* Calcification of the valve

* Infection of the valve (Rheumatic Fever is the most common)

* Heart attacks can also damage the valve

Problems with the Electrical Controls of the Heart

The electrical system controls how often, or how fast, the heart beats and coordinates the movements among the various chambers of the heart for optimal efficiency. Beating too fast, too slow, or irregularly can all result in heart failure. The generic name for these problems is an arrhythmia.

The normal heart rate is 60 to 80 beats per minute. The most common reason for the heart to beat to rapidly is excess stimulation, such as a thyroid problem. The most common reason for beating too slow is bad connection between the chambers (heart block). An irregularly beating heart is often caused by atrial fibrillation.

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Causes and Risk Factors of Congestive Heart Failure
The two most common causes of heart failure are high blood pressure and coronary artery disease (disease of the artery). Up to 75 percent of all patients with heart failure have a history of high blood pressure, and at least 50 percent have a history of coronary artery disease.

Specific causative factors for the four (4) forms of heart failure are listed below.

1. Systolic heart failure can be caused by coronary artery disease; high blood pressure; metabolic disorders, such as thyroid disease, vitamin deficiency or diabetes; infection; toxin exposure to cobalt, alcohol, cocaine and chemotherapeutic agents; infiltrative diseases, such as cardiac amyloidosis and hemochromatosis; neuromuscular disease; collagen vascular disease; valvular heart disease or peripartum cardiomyopathy.

2. Diastolic heart failure can be caused by coronary artery disease; high blood pressure; myocardial relaxation; left ventricular elastic recoil; ventricular-ventricular interaction; pericardial restraint; intrathoracic pressure or passive chamber properties.

3. Left-sided heart failure can be caused by high blood pressure; hypertrophic cardiomyopathy (an enlarged left ventricle and a thick ventricular wall); anemia; hyperthyroidism; heart valve defect, such as aortic valve stenosis and aortic insufficiency; congenital heart defect; heart arrhythmias; myocardial infarction or cardiomyopathy (disease of the heart muscle).

4. Right-sided heart failure can be caused by pulmonary hypertension; lung disease, such as chronic bronchitis and emphysema; tricuspid insufficiency or congenital heart defect, such as septal defect, pulmonary stenosis or tetralogy of Fallot.

Symptoms of Congestive Heart Failure
All of the types of heart failure can result in similar symptoms, including the following:

* Shortness of breath, especially with activity such as walking

* Difficulty breathing when lying flat in the bed

* Waking up at night short of breath

* Fatigue

* Weakness

* Pale, blue or cool skin

* Palpitations

* Changes in blood pressure

* Fainting for no apparent reason

* Swelling in the abdomen

* Swollen legs

Symptoms of right-sided heart failure include:

* Swollen legs

* Liver and spleen enlargement

* Swollen neck veins

* Fluid buildup in the stomach

* Swollen abdomen

* Slow weight gain

* irregular heart rhythm

* Nausea

* Vomiting

* Appetite loss

* Weakness

* Fatigue

* Dizziness

* Fainting episodes

Diagnosis of Congestive Heart Failure
A health history, physical exam, chest x-ray, and electrocardiogram (EKG) should be done in every person suspected of heart failure. Most patients will also have an echocardiogram (an ultrasound study of the heart). A blood test (BNP) can also be useful in diagnosing heart failure.

The health history will consist of questions about symptoms and how long they have been present, previous heart problems, other health problems, , and use of alcohol or other drugs.

During the physical exam, the doctor will listen to the heart and lungs with a stethoscope to detect the sounds associated with heart failure (such as murmurs or the sound of fluid in the lungs).

Additionally, the doctor will look for evidence of fluid build-up, such as swollen or enlarged neck veins, an enlarged liver, an expanding abdomen and swollen ankles.

A chest x-ray may reveal an enlarged heart or fluid in the lungs. It may also suggest another reason for the symptoms such as pneumonia or damage to the lungs.

An echocardiogram uses ultrasound waves to obtain images of heart structures. The echocardiogram can tell if the heart pumping ability is weak or stiff. It can also diagnose problems with the valves, or it may suggest that a person has had a previous heart attack.

Treatment of Congestive Heart Failure
The treatments for heart failure have improved dramatically over the last five to 10 years. Most subjects can be managed to the point where they have few symptoms, but this often requires that they take five or more medications per day.

When deciding how to treat heart failure, the most important question is what caused the heart failure in the first place and to reverse that if possible. If the problem is from a bad valve, surgery will usually be required to replace or repair the valve. If the problem is electrical, a pacemaker may be needed to regulate the heart beat or other treatments to slow the heart rate. If the problem is from blocked arteries, either an angioplasty or a bypass surgery is usually attempted. Most patients will end up taking several medications to improve their symptoms or help the heart recover.

Medication

The first treatment is usually a diuretic medication. These medicines work by forcing the kidney to excrete more salt and water. This will help to remove the excess fluid from the lungs and/or the legs. These medications can quickly make a patient feel better. Examples include furosemide (Lasix), bumetanide (Bumex), and hydrochlorothiazide (HCTZ).

Angiotensin-converting enzyme inhibitors (ACE inhibitors) are used to reduce the blood pressure and to encourage the healthy recovery of the heart function. They work by restoring imbalances in several hormones. There are approximately 10 different brands available with similar effectiveness. Examples include: captopril (Capoten), enalapril (Vasotec), and lisinopril (Prinivil, Zestril).

Some patients will develop a cough when treated with an ACE Inhibitor. They will usually be prescribed a closely related type of medication known as an angiotensin receptor blocker (ARB). Examples include valsartan (Diovan) and losartan (Cozaar).

Recently, some studies have suggested that African-Americans may not respond as well as other ethnicities to ACE inhibitors. They may instead be prescribed a combination of hydralazine and isosorbide. Beta-blockers were originally thought to be harmful for subjects with heart failure as they tend to reduce the pumping ability of the heart. They work by blocking the effect of adrenaline, a stress hormone, that can be very high in patients with heart failure. We now know that adrenalin is harmful to the heart. Beta blockers can dramatically improve the function of the heart over time, but if the heart muscle is weak, they must be started at low doses and gradually increased over time. Examples of beta-blockers include carvedilol (Coreg) and metoprolol (Toprol XL).

Digoxin (Lanoxin) has been used for several centuries to treat heart failure. It is an herbal extract that mildly increases the heart's pumping action so more blood is ejected with each heartbeat. Care must be taken to avoid high blood levels of this medication.

Other medications may also be needed to lower the blood pressure, lower the level of cholesterol, replace potassium lost in the urine, or prevent blood clots.

Electrical Devices:

* Defibrillators (ICDs) have been shown to prevent sudden cardiac death (a fatal arrhythmia) in certain groups of people with heart failure. These are small devices that are placed under the patient’s skin and monitor the electrical activity of the heart. If a problem is detected, the device will give the heart an electrical shock which is designed reset the heart and restore a healthy heart rhythm.

* Biventricular Pacemakers are advanced types of pacemakers that can stimulate both the right and left side of the heart at the same time if an electrical problem has caused them to become out of sync. These devices function much like typical pacemakers, but they require a more complicated installation to reach the left side of the heart.

Dietary, Lifestyle and Health Changes

* Restrict salt (sodium) intake. Restricting sodium minimizes fluid retention.

* Avoid caffeine. Avoiding caffeine lowers the risk of an increased heart rate or abnormal heart rhythms.

* Limit or stop alcoholic beverage consumption.

* Check your weight everyday. If your weight suddenly increases, you may be retaining fluid and may need to adjust your medications.

* Don't smoke or chew tobacco.

* Don't use illegal drugs.

* Exercise regularly, within your doctor's guidelines.

* Rest. Adequate rest helps conserve energy and decreases demands on the heart.

* Reduce stress.

* Get a flu and pneumonia shot.

Questions To Ask Your Doctor About Congestive Heart Failure
What form of heart failure is it?

What is the cause of the condition?

How serious is the condition?

Should a specialist be consulted?

What type of treatment will you be recommending?

Will surgery be recommended?

Will you be prescribing any medication?

What are the side effects?

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