Congestive Heart Failure

Definition

Congestive heart failure (or heart failure) is a chronic, progressive condition that occurs when the heart is unable to pump enough blood to the muscles, tissues and organs of the body.

Description

The heart circulates blood from two pumps, one located on the left side of the heart and one on the right side. Each pump contains an atrium (a receiving chamber) and a ventricle (an exiting chamber). The pumping action of the heart consists of three phases, which together make up a cycle corresponding to one heartbeat.

The first phase is called the diastole (or resting) phase. The second phase is called the atrial systole phase. The third phase is called the ventricular systole phase.

The diastole phase occurs when the heart fills with blood. Deoxygenated blood flows into the right side of the heart and oxygenated blood flows into the left side of the heart. In the atrial systole phase, the two atriums contract simultaneously, squeezing blood into the two ventricles which become fully filled. In the ventricular systole phase, the ventricles contract to pump deoxygenated blood into the pulmonary artery and oxygenated blood into the aorta.

Diseases that interfere with either the filling of the heart or its ability to squeeze blood forward can result in heart failure. There are four (4) forms of heart failure:

Systolic heart failure is the most common heart failure and occurs when the heart has difficulty pumping blood forward.
Diastolic heart failure occurs when the heart is unable to receive blood normally.
Left-sided heart failure occurs on the left side of the heart. The heart fails to empty completely with each contraction or has difficulty accepting blood returning from the lungs. This backup of blood in the lungs causes them to become congested with fluid. This condition is called pulmonary edema.
Right-sided heart failure occurs on the right side of the heart. The heart fails to empty completely with each contraction or has difficulty accepting blood returning from the body. This backup of blood in the venous system causes edema in the lower legs and ankles, and an enlarged liver and swollen neck veins. Right-sided heart failure is usually a result of left-sided heart failure.

Causes

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:

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.
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.
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).
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

Symptoms of left-sided heart failure include:

Shortness of breath
Difficulty breathing except when upright
Wheezing
Coughing
Oxygen shortage in the body
Pale or bluish skin
Palpitations
Irregular heart rhythm
Increased blood pressure

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

A health history, physical exam, chest x-ray, echocardiography (an ECG or an EKG), and if necessary, a radionuclide ventriculography, are used to diagnose heart failure. The health history will consist of questions about symptoms and how long they have been present, previous heart problems, general health history, current lifestyle 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).

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, swelling of the space between tissues and congestion in the lungs.

An echocardiography uses ultrasound to obtain an image of heart structures. The echocardiography usually reveals heart strain, an enlarged heart, poor blood supply to the heart, an enlarged atrium, a fast heart rate and premature heartbeats. A radionuclide ventriculography (also called radionuclide scanning) is a test that tracks very low doses of a radioactive substance as it travels through the heart.

Treatment

Although heart failure is progressive, cardiac deterioration can be slowed - perhaps even stopped - by using the proper combination of drugs in conjunction with diet, lifestyle and health changes. If a heart valve problem or coronary artery disease is suspected as the cause of the heart failure, heart surgery is usually recommended.

a) Medication

The first-line treatment of choice is the angiotensin-converting enzyme inhibitors (ACE inhibitors) captopril (Capoten), enalapril (Vasotec), and lisinopril (Prinivil, Zestril).

ACE inhibitors belong to a group of medications called vasodilators, which help in two ways. First, they decrease production of angiotensin, a hormone that constricts arteries. This allows the heart to empty more easily. Second, they decrease production of aldosterone, another hormone that causes the body to retain sodium and water.

Other drugs sometimes used in combination with ACE inhibitors include:

Hydralazine (Apresoline) and Isosorbide Dinitrate (Isordil), which are also vasodilators. These drugs further dilate the blood vessels and reduce the heart's workload.
Digitalis (digoxin (Lanoxin)) mildly increases the heart's pumping action so more blood is ejected with each heartbeat.
Diuretics, such as Bumetanide (Bumex) and Furosemide (Lairx), increase the rate at which the body makes urine. This reduces fluid and sodium that would usually accumulate in the tissues.
Inotropic (affecting the force of muscular contractions) agents, such as dobutamine Hydrochloride (Dobutrex), Amrinone Lactate (Incor) and Milrinone Lactate (Primacor), are now available for inotropic support.
Beta-blockers, such as Carvedilol (Coreg), improve blood flow.
Two newer calcium channel blockers, Amlodipine (Norvasc) and Felodipine (Plendil), as well as two beta-blockers (Propranolol (Inderal) and Metoprolol (Lopressor)), are being used in studies of heart failure. A-11 (angiotensin 11) antagonists, such as Losartan (Cozaar) and Valsartan (Diovan), work similar to ACE inhibitors by decreasing production of angiotensin and aldosterone.

b) 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.
Maintain proper weight.
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.
Avoid contact with people who have colds.
Get a flu and pneumonia shot.

c) Surgery

Heart valve surgery, coronary artery bypass graft (CABG) surgery, angioplasty, and heart transplant surgery are the options available.

Heart valve surgery replaces or repairs one or more heart valves.
CABG surgery uses veins or arteries from other parts of the body to bypass blocked coronary arteries on the heart and restore more normal blood flow to the heart.
Angioplasty involves the insertion of a catheter (a long, thin tube) into the arteries of the heart and then inflating a small balloon, located at the tip of the catheter. This inflation expands the coronary artery and crushes the blockage, restoring blood flow.
Heart transplantation is considered only in cases of very severe heart failure. This surgery involves removing the patient's heart and replacing it with a donor heart.