Systolic Heart Failure - Topic Overview
Gradual heart damage continued...
Chronic ischemia can allow your heart muscle to get just enough
oxygen to stay alive but not enough oxygen to work normally. Ongoing poor blood flow to the heart muscle reduces the heart's ability
to contract and causes it to pump less blood during each beat. The less blood
your heart pumps out to your body, the less blood it is actually pumping back
to itself through the coronary arteries. The end result is that heart failure
makes ischemia worse, which in turn makes heart failure worse.
Mitral valve regurgitation can gradually lead to systolic heart failure. With this problem, the mitral valve doesn't close properly, and blood leaks back into the left atrium when the left
ventricle contracts. Over time, the left ventricle pumps harder to move the
extra blood that has returned to it from the left atrium. The
ventricle stretches and gets bigger to hold the larger volume of
blood. Gradual weakening of the left ventricle may cause
High blood pressure can also gradually lead to heart failure. To pump against your high blood pressure, your heart has to
increase the pressure inside your left ventricle when it pumps. After years of
working harder to pump blood, your ventricle may begin to weaken. When this
happens, the pressure inside the weakened left ventricle will cause the
ventricle to expand, stretching out the heart muscle. This damaging process is
called dilation, and it impairs your heart's ability to squeeze forcefully. The
result is systolic heart failure.
Sudden heart damage
A heart attackdamages heart muscle suddenly. A heart attack can cut off the flow of blood to
your heart muscle so that your heart muscle doesn't get any oxygen. If your
heart muscle goes without oxygen for long enough, heart muscle can die. If a heart attack damages a very large area of heart muscle, it
is possible that the ability of your heart to pump blood will be suddenly
limited to such a degree that you develop systolic heart failure. But this sudden complication isn't common.
If you have a substantial heart attack that injures a large
area of the heart muscle, you may eventually develop heart failure, even if it
doesn't occur suddenly. This happens most commonly after you have had a heart
attack involving the anterior wall of the heart. After a large area of the
anterior wall is destroyed, the percentage of blood pumped with each beat
(ejection fraction) can be significantly less. As a result, the heart attempts
to change its shape to maximize its pumping efficiency, a process referred to
as left ventricular remodeling. Initially, the changes made to the heart wall
(myocardium) are beneficial. Over time though, the left ventricle dilates and
increases in size, which makes the heart less able to pump.