Learning About Heart Failure
Heart failure can involve the
left side of the heart, the right side or both.
However, it usually affects the left side first.
Each side is made up of two chambers: the
atrium, or upper chamber, and the ventricle, or
lower chamber. The atrium receives blood into
the heart, and the ventricle pumps it where it
needs to go. Heart failure occurs when any of
these chambers lose their ability to keep up
with the amount of blood flow.
Left-sided heart failure
Left-sided or left-ventricular (LV)
heart failure involves the left ventricle (lower
chamber) of the heart. Oxygen-rich blood travels
from the lungs to the left atrium, then on to
the left ventricle, which pumps it to the rest
of the body. Because this chamber supplies most
of the heart's pumping power, it's larger than
the others are and essential for normal
function.
If the left ventricle loses its
ability to contract, the heart can't pump with
enough force to push enough blood into
circulation. If it loses its ability to relax
because the muscle has become stiff, the heart
can't properly fill with blood during the
resting period between each beat.
In either case, blood coming
into the left chamber from the lungs may back
up, causing fluid to leak into the lungs. Also,
as the heart's ability to pump decreases, blood
flow slows down, causing fluid to build up in
tissues throughout the body. This excess fluid
or congestion explains the term congestive heart
failure.
Right-sided heart failure
The right atrium receives the
"used" blood that returns to the heart through
the veins; then the right ventricle pumps it
into the lungs to be replenished with oxygen.
Right-sided or right-ventricular (RV) heart
failure usually occurs as a result of left-sided
failure. When the left ventricle fails,
increased fluid pressure is, in effect,
transferred back through the lungs, ultimately
damaging the heart's right side. When the right
side loses pumping power, blood backs up in the
body's veins. This usually causes swelling in
the legs and ankles.
Heart failure development
Heart failure is usually a
chronic disease, meaning that it's a long-term
condition that tends to gradually become worse.
By the time someone is diagnosed, chances are
that the heart has been losing pumping capacity
little by little for quite a while. At first the
heart tries to make up for this by:
-
Enlarging. When the heart
chamber enlarges, it stretches more and can
contract more strongly, so it pumps more
blood.
-
Developing more muscle mass.
This allows the heart to pump blood with
more force
-
Pumping faster. This helps
to increase the output of the heart.
The body also tries to
compensate in other ways:
-
The blood vessels narrow to
keep blood pressure up, trying to make up
for the heart's loss of power.
-
The body diverts blood away
from less important tissues and organs to
maintain flow to the most vital organs, the
heart and brain.
These temporary measures mask
the problem of heart failure, but they don't
solve it. This helps explain why some people may
not become aware of their condition until years
after the heart begins its decline.
Eventually the heart and body
just can't keep up, and the person experiences
the fatigue, breathing problems or other
symptoms that usually
