Fainting (cont.)

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Heart structural conditions

Structural problems with the heart can cause fainting or syncope, either because there is a problem with the ability of the heart to adequately pump blood or because of valve problems. When the heart muscle becomes damaged or inflamed it may not have the ability to pump blood to meet the body's needs. Examples include a heart attack (myocardial infarction) or cardiomyopathy, in which the heart muscle weakens.

Heart valve conditions

Abnormalities with the heart valves can also cause fainting or syncope. The valves allow blood to go in the proper direction when the heart pumps. Valve diseases may include abnormal narrowing (stenosis) or leakage (insufficiency or regurgitation). Either situation can cause issues with maintaining adequate blood flow to the body.

Sudden cardiac death

In young people, especially athletes, fainting or syncope can occur because of abnormal thickening of parts of the heart muscle (hypertrophic cardiomyopathy). This may obstruct blood when it tries to leave the heart, especially when the heart is asked to beat harder during exercise. Sudden death in athletes may be foreshadowed by episodes of syncope.

Postural hypotension

Loss of intravascular fluid, that is the blood and water within the blood vessels, can also cause fainting or syncope. Usually, fainting will occur when a person stands up quickly from a lying or sitting position and there isn't enough time for the body to compensate by making the heart beat quicker, or having the blood vessels constrict to maintain the body's blood pressure and blood flow to the brain. This is referred to as postural hypotension.

Medically Reviewed by a Doctor on 12/2/2013

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