Heart Failure: Compensation by the Heart and Body - Topic Overview
How does the heart increase its stroke volume? To increase its stroke volume, your heart can try to:
Get more blood into your heart. If your left ventricle isn't doing a good job pumping blood out,
your heart can try to compensate by allowing more blood to fill the ventricle
before it pumps by expanding its size (dilating) to increase its volume. This
form of compensation may be helpful at first, but as the heart gets bigger and
bigger, there is more and more tension on the walls of the heart to pump out
the blood inside it. This increases the strain on the heart, making its
function worse over time.
Your heart can pump harder by developing stronger, thicker muscle. This
thickening of your heart muscle is called hypertrophy, and it can help your
heart pump more forcefully and increase your stroke volume. But
hypertrophy of the heart muscle increases the heart's need for oxygen and other
nutrients. These requirements can eventually outstrip the blood supply to the
heart, leading to further weakening of the heart muscle. In addition,
hypertrophy of the walls of the heart can make diastolic function worse by
impairing the ability of the heart to relax properly. This limits the heart's
ability to fill with blood, which can also further reduce cardiac
What happens when your body can no longer compensate?
If your body can no longer compensate for heart failure, you will begin to have symptoms, which consist of two major types:
Congestive symptoms, which are caused by the
backup of blood into the lungs and the other organs of the body. These symptoms
include shortness of breath and swelling in the ankles and
Low-output symptoms, which are caused by the inability of
the heart to generate enough cardiac output, leading to reduced blood flow to
the brain and other vital organs. These symptoms may include lightheadedness,
fatigue, and low urine output. If the cardiac output is very low, this can
damage organs, particularly the kidneys.
How long does it take before the body stops compensating for heart failure? Your body can compensate for heart
failure for a long time, often for many years. But the duration of
compensation can be extremely variable and depends on the cause of your heart
failure and whether you have other medical problems.