These tests evaluate many aspects of your physical condition
that your doctor is not able to measure by talking to you or doing a physical
exam. The following section outlines the type of information your doctor can
obtain about the structure and function of your heart from diagnostic
Edema is the medical term for swelling. It is a general response of the body to injury or inflammation. Edema can be isolated to a small area or affect the entire body. Medications, infections, pregnancy, and many medical problems can cause edema.
Edema results whenever small blood vessels become "leaky" and release fluid into nearby tissues. The extra fluid accumulates, causing the tissue to swell.
Important features about the structure of your heart
Overall size of your heart. If you have systolic heart failure, you probably have a dilated,
enlarged heart. In this case, the more your heart is enlarged, the worse your
expected outcome (prognosis) is. Ongoing high blood pressure also can cause
left ventricular hypertrophy, which can also result in an enlarged heart.
Size of each chamber of the heart.
Different causes of heart failure can be associated with enlargement of
different chambers of the heart, and the pattern of enlargement therefore can
provide important clues about the cause of heart failure. For example, mitral
valve stenosis is usually associated with a very large left atrium, but a
normal-sized left ventricle. In contrast, mitral valve regurgitation is
associated with significant enlargement of both of these
Shape of your heart. Types of
systolic heart failure that affect all chambers of the heart equally will
usually cause a dilated heart, thinning of all of the heart's walls, and poor
pumping ability. Systolic heart failure from a large heart attack, on the other
hand, will predominantly cause only one wall of the heart to function poorly.
Diastolic heart failure from chronic high blood pressure (hypertension) often
causes a moderately enlarged heart with very thick walls.
Thickness and motion of the walls of your heart. Some causes
of heart failure result in thinning and decreased motion of all the muscular
walls of the heart; this is characteristic of dilated cardiomyopathy that is
inherited or caused by mitral valve regurgitation or toxins such as alcohol. In
contrast, heart failure caused by coronary artery disease is usually associated
with thinning and decreased motion of the walls of the heart where heart
attacks have occurred, but slightly thicker and more forcefully contracting
walls in the other regions that are attempting to compensate for the damaged
walls. Diastolic heart failure caused by chronic high blood pressure is
characteristically associated with very thick walls of the heart that may be
functioning more forcefully than in a normal heart.
Left ventricular ejection fraction (LVEF). This measurement
represents the fraction of blood that is in the left ventricle when it relaxes
between beats that is successfully pumped out during contraction. The normal
LVEF is more than 55%. In severe systolic heart failure, the LVEF can be as low
as 10% to 20%. The LVEF is the single best predictor of survival in people with
systolic heart failure.
Function of the valves. An
echocardiogram is the best test to evaluate the
function of the heart valves. Leakage or blockage of the valves on the left
side of the heart (the mitral and aortic valves) can cause left-sided heart
failure, and abnormal function of the valves on the right side (the tricuspid
or pulmonic valves) can cause right-sided heart failure.
Degree of blockage of the coronary arteries. This information
is crucial to rule out severe coronary artery disease as a cause of heart
failure. In older people or in people with risk factors for coronary artery
disease, it is often necessary to perform a stress test or coronary angiogram
to make sure that the coronary arteries are not severely blocked.
Effect of stress on the heart. The effect of different
forms of stress such as exercise or medicines on the heart can provide
information about the cause and severity of heart failure.
Electrical activity of the heart. The identification of
abnormal heart rhythms such as atrial fibrillation or ventricular tachycardia
may suggest that one of these abnormal heart rhythms is the cause of heart
failure. But more importantly, the identification of such an abnormal rhythm
would suggest that the person is at risk for a serious complication of heart
failure and may require more specialized treatment.
Thickness of the pericardium and the presence of pericardial fluid. The pericardium is the thin sac that surrounds your heart. A
thick, calcified pericardium suggests that heart failure is caused by
constriction of the heart by a diseased pericardium. If the pericardium is
filled with fluid (pericardial effusion), this may suggest an inflammatory or
infectious cause of your heart failure.
Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
Robert A. Kloner, MD, PhD - Cardiology
August 5, 2010
WebMD Medical Reference from Healthwise
August 05, 2010
This information is not intended to replace the advice of a doctor.
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