Congestive Heart Failure


Congestive heart failure (CHF) or simply heart failure, is a condition where the heart fails to pump adequate blood to meet the body's need. Unlike a heart attack, the heart does not stop beating - rather, it weakens over the course of months or years so that it cannot pump enough blood. As a result, pulmonary congestion or fluid build up occurs in the lungs.

Enlarged cardiac sillhouette in congestive heart failure
Enlarged heart and accumulation of fluids in the lungs in congestive heart failure.

There are several ways that the heart can fail:

  • Weakened heart muscle
    Muscles of the pumping chamber of the heart can become so stretched and weakened that the heart cannot pump enough blood to reach all of the body's tissues.

  • Loss of elasticity of the heart muscle
    The heart muscle can become stiffened or thickened. This prevents enough blood from filling the pumping chamber, and as a result, not enough blood is pumped out.

  • Abnormal heart valves
    Stenosis or narrowing of the heart valves (such as aortic valve stenosis, mitral valve stenosis, pulmonary valve stenosis) and prolapse or floppy valves (such as mitral valve prolapse) can increase the workload of the heart.

  • Heart remodeling
    To compensate for inefficient pumping, the heart can undergo irreversible structural changes called heart remodeling. In some cases, the left ventricle can enlarge and change shape. There are changes at the cellular level as well, such as early cell death that causes the heart muscle cell to die.

There are two types of heart failures:

  • Systolic dysfunction or failure
    This type of heart failure is the most common type. It occurs during the systolic or contraction phase, and affects the left side of the heart. Here, the left ventricle is usually enlarged and fluid accumulates in the lungs.

  • Diastolic dysfunction or failure
    This type of failure occurs during the diastolic or relaxtion phase, and usually affects the right side of the heart. It is usually caused by thickened heart muscle which prevents the heart to relax completely. As a result, blood cannot efficiently enter the heart and backs up in the veins and surrounding heart tissue.

Symptoms of Heart Failure

The symptoms of congestive heart failure include:

  • Fatigue
  • Shortness of breath, especially during physical activity or when lying down
  • Wheezing or dry cough, especially when lying down
  • Sleep apnea, or disordered or inability to breathe at night
  • Loss of appetite and weight loss (loss of muscle mass)
  • Swelling of the feet, ankles, and legs
  • Swelling or discomfort in the upper abdomen, sometimes enlargement of the liver

When fluid builds up in the lungs in a condition called pulmonary edema, the patient may have the following symptoms:

  • Cough with pink froth
  • Shortness of breath
  • Sensation of drowning, or bubbling in the lungs
  • Clammy, pale, and bluish-tinged skin.

These symptoms (especially the symptoms of pulmonary edema) are serious and require immediate medical help.

Diagnosis

Your doctor would perform the following tests to diagnose this condition:

  • Physical examination
    Irregular heart sound, such as ventricular gallop or a distinct hearbeat can be heard using a stethoscope. Rales or crackling breath can also be heard. Enlarged and tender liver, swollen feet and legs, fluid retention and elevated pressure on the neck veins and arteries can also be diagnosed.

  • Chest X-Ray and Electrocardiogram
    Enlarged heart can be seen using a chest x-ray and electrocardiogram (ECG). Abnormal heart rhytm can also be visualized with an ECG.

  • Echocardiography
    Also called Doppler flow test, echocardiography is the best diagnostic test for congestive heart failure. Here, ultrasound is used to visualize the beating heart, valve function, and blood flow. By calculating the ejection fraction or amount of blood pumped out during a heartbeat, your doctor can determine the severity of the condition.

  • Coronary Angiography
    In this test, a catheter is inserted into the heart to measure internal blood pressure.

Causes of Congestive Heart Failure

Increased workload and stress on the heart caused by the following conditions can lead to heart failure:

  • Heart Attack
    Thanks to modern medicine and prompt treatment, heart attack or myocardial infarction is now very survivable. The attack itself, however, can lead to dramatic increase in developing congestive heart failure.

  • Coronary Artery Disease or Atherosclerosis
    In this condition, the arteries of the heart is blocked by atherosclerotic plaque deposit.

  • High Blood Pressure
    In addition to directly causing a heart attack or myocardial infarction, hypertension or high blood pressure can also cause heart failure without an attack. High blood pressure causes the heart muscle to thicken, and over time the increased force to pump blood can cause it to weaken.

    High blood pressure is implicated in over 75% of all cases of heart failure.

  • Heart Valve Abnormalities
    Abnormal narrowing or improper closing of the valve leaflets can interefere with blood flow and cause the heart to work harder.

    Left untreated, diseases such as rheumatic fever can cause scarring of the heart valves. Most heart valve abnormalities, however, occurs during fetal development and is congenital or present at birth.

  • Cardiomyopathies
    These diseases damage the heart muscles and causes them to become too thin or too thick.

    In Idiopathic Dilated Cardiomyopathy, the heart ventricle become enlarged and the muscles become too thin. Although the cause is unknown, it is thought that viral infection triggers the body's own immune system to erroneously attack and kill heart muscle cells.

    In Hypertrophic Cardiomyopathy, it is thought that loss of power in the heart muscle cells cause the heart to compensate by building more (and thus thickening) the heart muscle. This rare condition often made news as the cause of death of young athletes.

    Chronic alcohol abuse can also reduce the heart muscle's effectiveness and cause damage leading to cardiomyopathy.

  • Remodeling of the heart
    Remodeling is structural and cellular change of the heart in response to impaired heart functions.

    For example, to compensate for increased input due to high blood pressure, the heart can grow in size or enlarge. This is often done by elongation of the heart muscle cells, which result in thinner and weaker cell walls. The cell muscle itself becomes thinner and weaker.

    To compensate for weakened pumping action, the nervous sytem can signal the heart to beat faster. In the long run, this actually create more damage.

    The body's blood vessel can also change: to compensate for lower blood flow, they constrict and become more narrow. In turn, this cause the heart to work harder and beat faster thus increasing blood pressure and compounding the vicious cycle that will ultimately lead to heart failure.

  • Various Other Diseases
    Hyperthyroid disease or other tachycardias (rapid heart rate) can stress the heart by increasing its workload.

Risk Factors for Congestive Heart Failure

About 5 million people in the United States suffer from this condition, and every year about 500,000 new cases are reported. About 250,000 people die every year because of heart failure.

The risk factors of congestive heart failure include:

  • Age
    Since this disease is a progressive condition (ie. it worsen with time), the risk of heart failure is increased with age. It is now the most common reason for hospitalization in the elderlies.

  • Genetics
    Tendency to develop heart failure, especially when caused by cardiomyopathies, may run in families. It is important to note that dietary habit of the family must be taken into account: when all members of the family eat high fat, high cholesterol diet, this maybe the underlying cause of atherosclerosis, not genetics.

  • Gender
    Men are at higher risk of developing heart failure than women, although the difference narrows with advancing age.

  • Ethnicity
    African Americans are at higher risk than Caucasians, and have higher mortality rate due to heart failure. Afrian Americans tend to develop diastolic heart failure (inability of the heart to relax properly), whereas Caucasians tend to develop systolic failure (inability to pump blood) first.

  • Alcohol Abuse and smoking
    Chronic alcohol use can lead to high blood pressure, heart muscle damage, and even cause cardiomyopathy. The carbon monoxide in cigarettes is thought to damage the heart muscle and increase its susceptibility to virus infection.

  • Exercise and Dietary Habits
    Sedentary lifestyle, lack of exercise and eating fatty foods can increase the risk of developing coronary artery disease, which lead to heart failure.

  • Presence of Other Diseases
    In addition to coronary artery disease, previous heart attack, high blood pressure, and valve abnormalities, other diseases such as diabetes, emphysema, HIV-infection and other infection-caused cardiomyopathies, hyperthyroidism, amyloidosis, and myocarditis can lead to increased risk of heart failure.

    In rare instances, women can also suffer heart failure during childbirth in a condition called peripartum cardiomyopathy.

  • Side Effects of Medications
    Older chemotherapy used to treat childhood cancers, use of anabolic steroids, and certain anti-fungal drugs can lead to heart failure.

  • Vitamin Deficiency
    Lack of thiamin (vitamin B1) can lead to cardiomyopathy. Luckily, this condition is reversible by adding enough vitamin B to the diet.

Congestive Heart Failure Treatment

Treating heart failure almost always mean treating the underlying cause of this condition. These include lifestyle changes (stop smoking and stop drinking alcohol) and dietary changes (eat healthier food, stop eating fatty diets) to treat coronary artery disease, treating high blood pressure and heart valve abnormalities, and so forth.

Medicines that improve heart function can also be prescribed:

  • Diuretics
    Also called water pills, diuretics reduce the volume of blood and decreases congestion or fluid build ups by inducing the kidney to release salt. This reduces the blood pressure and lightens the workload of the heart.

  • Angiotensin-Converting Enzyme (ACE) Inhibitors
    These medications lower the blood pressure by enlarging or dilating the arteries and also by reducing the volume of blood.

    ACE Inhibitors significantly reduce the death rate associated with heart failure, and therefore becomes the front-line medications for this disease.

  • Other Vasodilators
    For some reason, ACE Inhibitors are less effective in African Americans. In addition to this medicine, other vasodilators (medicines that dilate the blood vessels) such as hydralazine and nitrates are often used.

  • Inotropic medications
    These drugs strengthen the heart's contraction so it can pump better. These include digitalis (digoxin), dopamine, and others.

  • Beta blockers
    In combination with other medications, beta blockers can be prescribed to slow the heart rhythm. Beta blockers should be used with caution since they can also decrease the pumping efficiency of the heart.

Severe heart failure may require surgery, such as baloon dilaton of artery blockages, heart transplantation, pacemaker implants to control the heart rhythm, and insertion of portable pumps to infuse medications. In cases of valve defects, surgery to repair or replace the damaged valves may be necessary.

Prognosis

The prognosis of heart failure is fair to poor, although advances in medicine continues to greatly increase expected lifespan. The annual mortality in people with mild, stable symptoms of heart disease is about 10%. In those with severe and progressive disease, the mortality rate can be as high as 50%.







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