Heart murmurs are heart sounds produced when blood flows across one of the heart valves that is loud enough to be heard with a stethoscope. There are two types of murmurs. A functional murmur or “physiologic murmur” (also called innocent murmur) is a heart murmur that is primarily due to physiologic conditions outside the heart.
There are also murmurs caused by narrowing or leaking of valves, also known as “Pathologic murmurs”. These murmurs are caused by defective heart valves. A stenotic heart valve has a smaller-than-normal opening and can’t open completely. A valve may also be unable to close completely. This leads to regurgitation, which is blood leaking backward through the valve when it should be closed. Murmurs also can be caused by certain congenital defects and other conditions such as pregnancy, fever, thyrotoxicosis (a diseased condition resulting from an overactive thyroid gland) or anaemia.