Definition
Heart failure, also called "congestive heart failure," is a
disorder where the heart loses its ability to pump blood
efficiently. The result is that the body doesn't get as much oxygen
and nutrients as it needs, leading to problems like fatigue and
shortness of breath. Heart failure is almost always a chronic,
long-term condition that is managed with medications and lifestyle
changes. (Although it can sometimes develop suddenly.)
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Radiographic Appearance
- Although diagnostic tests are of limited benefit in acute
CHF, chest x-ray (CXR) is the most useful tool.
- Cardiomegaly may be observed with a cardiothoracic ratio
greater than 50%. Pleural effusions may be present bilaterally
or, if they are unilateral, are more commonly observed on the
right.
- Early CHF may manifest as cephalization of pulmonary
vessels, generally reflecting a pulmonary capillary wedge
pressure (PCWP) of 12-18 mm Hg. As the interstitial fluid
accumulates, more advanced CHF may be demonstrated by Kerley B
lines (PCWP: 18-25 mm Hg).
- Pulmonary edema is observed as perihilar infiltrates often
in the classic butterfly pattern reflecting a PCWP greater than
25 mm Hg.
- Several limitations exist to the use of chest x-rays when
attempting to diagnose CHF. Classic radiographic progression
often is not found, and as much as a 12-hour radiographic lag
from onset of symptoms may occur. In addition, radiographic
findings frequently persist for several days despite clinical
recovery.
Ref: Grossman. Emedicine Textbook. Congestive
Heart Failure and Pulmonary Edema. Plantz and Adler, editors. 2002
Ref: http://www.nursingceu.com/NCEU/courses/chf/
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Pathology
Congestive heart failure (CHF) is an imbalance in pump function in
which the heart fails to maintain the circulation of blood
adequately. The most severe manifestation of CHF, pulmonary edema,
develops when this imbalance causes an increase in lung fluid
secondary to leakage from pulmonary capillaries into the
interstitium and alveoli of the lung.
CHF can be categorized as forward or backward ventricular failure.
Backward failure is secondary to elevated systemic venous pressure,
while left ventricular failure is secondary to reduced forward flow
into the aorta and systemic circulation. Furthermore, heart failure
can be subdivided into systolic and diastolic dysfunction. Systolic
dysfunction is characterized by a dilated left ventricle with
impaired contractility, while diastolic dysfunction occurs in a
normal or intact left ventricle with impaired ability to relax and
receive as well as eject blood.
The New York Heart Association's functional classification of CHF is
one of the most useful. Class I describes a patient who is not
limited with normal physical activity by symptoms. Class II occurs
when ordinary physical activity results in fatigue, dyspnea, or
other symptoms. Class III is characterized by a marked limitation in
normal physical activity. Class IV is defined by symptoms at rest or
with any physical activity.
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Treatment:
Use of diuretics, nitrates, analgesics, and inotropic agents are
indicated for the treatment of CHF and pulmonary edema. Calcium
channel blockers, such as nifedipine and nondihydropyridines,
increase mortality and increase incidence of recurrent CHF with
chronic use. Conflicting evidence currently exists in favor, as well
as against, the use of calcium channel blockers in the acute
setting; at this time limit their acute use to patients with
diastolic dysfunction and heart failure, a condition not easily
determined in the ED
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Images
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- The cardiac silhouette is enlarged.
- The pulmonary hila are prominent.
- The pulmonary vasculature is engorged.
- Peri-hilar infiltrates are present in a "bat-wing"
distribution.
- Upright or decubitus films may demonstrate pleural fluid (R >
L).
- Upright film may demonstrate pulmonary vascular
redistribution.
- Cardiac size is better evaluated on a PA film.
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Useful Link
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