What is congestive heart failure (CHF)?
Heart failure describes the inability or failure of the heart to adequately meet the needs of organs and tissues for oxygen and nutrients. This decrease in cardiac output, the amount of blood that the heart pumps, is not adequate to circulate the blood returning to the heart from the body and lungs, causing fluid (mainly water) to leak from capillary blood vessels. This leads to the symptoms that may include shortness of breath, weakness, and swelling.
Understanding blood flow in the heart and body
The right side of the heart pumps blood to the lungs while the left side pumps blood to the rest of the body. Blood from the body enters the right atrium though the vena cava. It then flows into the right ventricle where it is pumped to the lungs through the pulmonary artery. In the lungs, oxygen is loaded onto red blood cells and returns to the left atrium of the heart via the pulmonary artery. Blood then flows into the left ventricle where it is pumped to the organs and tissues of the body. Oxygen is downloaded from red blood cells while carbon dioxide, a waste product of metabolism, is added to be removed in the lungs. Blood then returns to the right atrium to start the cycle again.
Left heart failure occurs when the left ventricle cannot pump blood to the body and fluid backs up and leaks into the lungs causing shortness of breath. Right heart failure occurs when the right ventricle cannot adequately pump blood to the lungs. Blood and fluid may back up in the veins that deliver blood to the heart. This can cause fluid to leak into tissues and organs.
It is important to know that both sides of the heart may fail to function adequately at the same time and this is called biventricular heart failure. This often occurs since the most common cause of right heart failure is left heart failure.
What causes congestive heart failure?
Many disease processes can impair the pumping efficiency of the heart to cause congestive heart failure. In the United States, the most common causes of congestive heart failure are:
- Coronary artery disease
- High blood pressure (hypertension)
- Longstanding alcohol abuse
- Disorders of the heart valves
- Unknown (idiopathic) causes, such as after recovery from myocarditis
Less common causes include viral infections of the stiffening of the heart muscle, thyroid disorders, disorders of the heart rhythm, and many others.
It should also be noted that in patients with underlying heart disease, taking certain medications can lead to the development or worsening of congestive heart failure. This is especially true for those drugs that can cause sodium retention or affect the power of the heart muscle. Examples of such medications are the commonly usednonsteroidal anti-inflammatory drugs(NSAIDs), which include ibuprofen (Motrin and others) and naproxen (Aleve and others) as well as certain steroids, some medication for diabetes (such asrosiglitazone [Avandia] or pioglitazone[Actos]), and some calcium channel blockers (CCBs).
What are the signs and symptoms of congestive heart failure?
The hallmark and most common symptom of left heart failure is shortness of breath.
Shortness of breath may occur:
- While at rest,
- With activity or exertion,
- While lying flat (orthopnea),
- May awaken the person from sleep(paroxysmal nocturnal dyspnea).
Shortness of breath may be due to fluid (water, mainly) accumulation in the lungs or the inability of the heart to be efficient enough to pump blood to the organs of the body when called upon in times of exertion or stress.
Chest pain or angina may be associated, especially if the underlying cause of the failure is atherosclerotic heart disease.
The New York Heart Association has developed a scale that is commonly used to determine the functional capabilities of a patient with heart failure.
Patients with right heart failure leak fluid into the tissue and organs that deliver blood to the right heart through the vena cava. Back pressure in capillary blood vessels cause them to leak water into the space between cells and commonly the fluid can be found in the lowest parts of the body. Gravity causes fluid to accumulate in the feet and ankles but as more fluid accumulates, it may creep up to involve all of the lower legs. Fluid can also accumulate within the liver causing it to swell (hepatomegaly) and also within the abdominal cavity (ascites). Ascites and hepatomegaly may make the patient feel bloated, nauseated, and have abdominal pain with the feeling of distension.
Depending upon their underlying illness and the clinical situation, patients may have symptoms of right heart failure, left heart failure, or both.
How is congestive heart failure diagnosed?
Diagnosis of congestive heart failure is able to be accomplished by history and physical examination. The health care professional often will ask question about the symptoms like shortness of breath, swelling in the legs, chest pain, and what the patient does to make them better (sit down, rest). It will also be important to know whether the symptoms have come on gradually or over a shorter period of time.
Past medical history, medication history, diet, and social history including alcohol and drug use are all important to share. Should congestive heart failure be thought to be caused by atherosclerotic heart disease, risk factors for heart disease may be explored.
Physical examination begins with observing the patient to decide how comfortable they are at rest and whether the walk to the exam area made them short of breath. Vital signs including blood pressure, pulse rate, respiratory rate, oxygen saturation, and body weight may be helpful to assess how ill the patient might be. The exam often concentrates on the heart and lungs.
When examining the lungs, the medical caregiver determines if there is good air entry in both sides of the chest or if there are extra sounds that might be heard when fluid is present. Tapping on the chest (percussion) can uncover a fluid buildup.
Heart exam includes feeling for the apex beat, the heart beat that can be felt through the chest wall. If it is displaced in the direction of the armpit, it may be a sign that the heart is enlarged. Listening to the heart sounds may uncover abnormal beats called gallops that are heard in heart failure. Murmurs may help diagnose heart valve disease. Rubs are noises made when the pericardium or fibrous sac covering the heart has become inflamed or enlarged.
The neck may be examined looking for jugular venous distention. The jugular veins will dilate if there is extra fluid in the body and may be a sign of right heart failure. Peripheral edema (tissue swelling) is also found in right heart failure. The doctor will often look at the feet and ankles first to see if they are swollen. The abdominal examination may reveal an enlarged liver or ascites (fluid accumulation in the abdominal cavity).
Congestive heart failure can be a medical emergency, especially if it acutely decompensates and the patient can present extremely ill with the inability to breathe adequately. In this situation, the ABCs of resuscitation (Airway, Breathing, Circulation) need to be addressed while at the same time, the diagnosis of congestive heart failure is made.
Common tests that are done to help with the diagnosis of congestive heart failure include the following:
- Electrocardiogram (EKG, ECG) to help assess heart rate, rhythm, and indirectly, the size of the ventricles and blood flow to the heart muscle.
- Chest X-ray to look at heart size and the presence or absence of fluid in the lungs.
- Blood tests may include a complete blood count (CBC), electrolytes,glucose, BUN, and creatinine (to assess kidney function).
- B-type natriuretic peptide (BNP) may be helpful in deciding if a patient has shortness of breath from congestive heart failure or from a different cause. It is a chemical that is located in the heart ventricles and may be released when these muscles are overloaded.
- Echocardiography or ultrasound testing of the heart is often recommended to assess the anatomy and the function of the heart. In addition to being able to evaluate the heart valves and muscle, the test can look at blood flow within the heart, watch the chambers of the heart contract, and measure the ejection fraction.
Other tests may be considered to evaluate and monitor a patient with suspected congestive heart failure, depending upon the clinical situation.
What is the treatment for congestive heart failure?
The goal of treatment for congestive heart failure is to have the heart beat more efficiently so that it can meet the energy needs of the body. Specific treatment depends upon the underlying cause of heart failure.
Treatment may try to decrease fluid within the body so that the heart does not have to work as hard to circulate blood through the blood vessels in the body.
Fluid restriction and a decrease in salt intake may be very helpful. Diuretic medications (water pills) may be prescribed if appropriate. Common diuretics include furosemide (Lasix), bumetanide (Bumex), and hydrochlorothiazide.
Medications are available that can make the heart pump more efficiently, increase cardiac output, and increase ejection fraction.
ACE inhibitors (angiotensin converting enzyme inhibitors) and ARBs (angiotension receptor blockers) are medicines that are also shown to increase survival by decreasing hypertension; they are often used with other drugs. Beta blockers may control heart rate and increase cardiac output and ejection fraction. Digoxin(Lanoxin) is an older medicine that may help increase cardiac output and control symptoms.
Cardiac risk factor modification is the cornerstone of prevention but may also benefit patients with established congestive heart failure.
Weight loss, establishing an exercise program, stopping smoking, and controlling high blood pressure, high cholesterol, and diabetes may help in the management of congestive heart failure.
End stage congestive heart failure (NYHA stage IV) patients may require aggressive treatments including left ventricular assist devices (LVAD), an implanted pump that helps increase the heart’s ability to squeeze, or even heart transplantation.