1. Health
Send to a Friend via Email

Congestive Heart Failure

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of CHF.

Alternative Names

Cardiomyopathy; Heart Failure

Diagnosis

Physicians can often make a preliminary diagnosis of heart failure with only a medical history and careful physical examination. An English study suggests, in fact, that the condition may be under-diagnosed. The following signs along with a history of heart disease strongly suggest heart failure:

  • Enlarged heart.
  • Irregular heart sounds.
  • Abnormal sounds in the lungs.
  • Swelling or tenderness of the liver.
  • Fluid retention.
  • Elevation of pressure in the veins of the neck.

Confirming these findings definitely or determining the severity of the condition, however, is difficult. Further tests are usually needed.

Laboratory Tests for Associated Medical Conditions

Both blood and urine tests are used to check for malfunctions of the liver and kidneys and to detect signs of diabetes.

Blood tests can also be used to evaluate the following:

  • Cholesterol and lipid levels.
  • Anemia.
  • Thyroid disease.

Urine tests can also be used to assess:

  • Albumin. The presence of this protein in the urine is usually a sign of kidney disease, but even tiny amounts (microalbumin) signal an increased risk for heart failure in people with and without diabetes.

Exercise Stress Test

The exercise stress test measures heart rate, blood pressure, and oxygen consumption while a patient is performing physically, usually walking on a treadmill. It is an important diagnostic component in determining heart failure symptoms. Doctors also use exercise tests to gauge long-term outlook and the effects of particular treatments.

Electrocardiogram

An electrocardiogram (ECG) cannot diagnose heart failure, but it is simple and painless to perform and can indicate underlying heart problems by detecting the following:

  • Enlargement of the heart muscle, which may help to determine long-term outlook.
  • The presence of coronary artery disease.
  • Abnormal cardiac rhythms. A rhythm pattern called a prolonged QT interval, for example, might predict people with heart failure who are at risk for severe complications and would need more aggressive therapies.

The major benefit of an ECG is help in determining patients who most likely do not need an echocardiogram, a more accurate (but more expensive) diagnostic test.

ECG
The electrocardiogram (ECG, EKG) is used extensively in the diagnosis of heart disease, from congenital heart disease in infants to myocardial infarction and myocarditis in adults. Several different types of electrocardiogram exist.

Echocardiography

The best diagnostic test for congestive heart failure is echocardiography coupled with studies known as Doppler flow. Echocardiography is a noninvasive, entirely safe test that uses ultrasound to image the heart as it is beating. Cardiac ultrasounds provide the following information:

  • Accurate indications of valve function.
  • The amount of blood flow through the hearts chambers.
  • The location of the failure, whether has occurred on the left side, the right side, or both.

Physicians use information from the echocardiogram for calculating the ejection fraction (the percent of the blood pumped out during each heartbeat), which is important for determining the severity of heart failure.

Imaging Tests

Radionuclide Ventriculography. Radionuclide ventriculography is an imaging technique that employs the injection of a tiny amount of radioactive material (called a trace element). As this substance passes through the bloodstream it is picked up on x-rays. This is a very important imaging technique for heart failure patients. It is very sensitive in revealing heart enlargement or evidence of fluid accumulation around the heart and lungs. It is typically used in concert with angiography.

Contrast Enhanced Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) scans that use contrast dies to improve resolution are proving helpful for identifying patients with irreversible heart damage. Damage appears as very bright areas on the scan.

Angiography

Physicians may recommend angiography if they suspect that blockage of the arteries is contributing to heart failure. This procedure is invasive and involves the following:

  • A thin tube, or catheter, is inserted into one of the large arteries in the arm or leg.
  • It is gently guided through the artery until it reaches the heart.
  • The catheter measures internal blood pressure at various locations, giving the physician a comprehensive picture of the extent and nature of the heart failure.
  • Dye is then injected through the tube into the heart.
  • X-rays known as angiograms are taken by following the dyes movement through the heart and arteries.
  • These images help locate problems in the hearts pumping action or blockage in the arteries.

Major complications of angiography are rare (about 0.1%) but can occur. They include stroke, heart attacks, and kidney damage. The more experienced the medical center in this procedure, the lower the risk.

Click the icon to see an image of cardiac catheterization.

Tests for Markers

Researchers are looking for biologic factors (called markers) that will confirm a diagnosis or suggest a better or worse prognosis. Many are under investigation. Examples are the following.

Tumor Necrosis Factor. Elevated levels of tumor necrosis factor (TNF) may be a very strong and accurate predictor of a poor outlook. This immune factor is known to be a potent agent in the inflammatory process.

Natriuretic Peptides. These compounds may be elevated in response to the heart failure disease process and may help doctors determine whether a particular treatment is working. Of special interest is one called B-type natriuretic peptide (BNP), which may be associated with greater heart rate variability and severity in heart failure patients.

Brain Metabolites. High levels of a compound called N-acetylaspartate, generated as a byproduct of chemical processes in the brain, may indicate a poor outlook.

adam.com

©2014 About.com. All rights reserved.