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Heart Murmurs
What causes a heart murmur?
A heart murmur is the sound heard (usually with a stethoscope) over the chest which arises from the flow of blood in the heart or related blood vessels. Heart murmurs may be caused by a number of factors or diseases, including:
- defective heart valves
- holes in the heart walls
- pregnancy
- fever
- anemia (a decrease in the red cells in the blood)
Heart murmurs may also be physiologic or functional, meaning that they do not have any clinical significance. A discussion with your doctor will help to clarify the cause of your heart murmur.
What are the different types of murmurs?
All murmurs are analyzed for pitch, loudness, and duration. They are also graded according to their intensity (on a scale of one to six, with one being very faint and six being very loud).
Types of murmurs include:
- systolic murmur - occurs during a heart muscle contraction. Systolic murmurs are divided into ejection murmurs (due to blood flow through a narrowed vessel or irregular valve) and regurgitant murmurs.
- diastolic murmur - occurs during heart muscle relaxation between beats. Diastolic murmurs are due to a narrowing of the mitral or tricuspid valves, or regurgitation of the aortic or pulmonary valves.
- continuous murmur - occurs throughout the cardiac cycle.
