Medical Health Encyclopedia

Heart murmurs and other sounds

In addition, a murmur is described by the stage of the heartbeat when the murmur is heard. The following are important clues to the cause of the murmur:

• Does the murmur occur in the resting stage (diastole) or contracting stage (systole)?
• Does it occur early or late in the stage?
• Does it occur throughout the heartbeat?

For example, a presystolic murmur is heard just BEFORE systole and is usually caused by narrowing of the mitral or tricuspid valve (the valves between the atria and the ventricles).

The location where the health care provider hears the murmur loudest is also often noted.

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Common Causes:

significant murmurs can be caused by:

• mitral regurgitation - chronic
• mitral regurgitation - acute
• mitral stenosis
• aortic regurgitation
• aortic stenosis
• tricuspid stenosis
• tricuspid regurgitation
• pulmonary stenosis
• pulmonary regurgitation (backflow of blood into the right ventricle, caused by failure of the the pulmonary valve to close completely)

Significant murmurs in children are more likely to be caused by:

• patent ductus arteriosus (PDA)
• atrial septal defect (ASD)
• ventricular septal defect (VSD)
• coarctation of the aorta
• anomalous pulmonary venous return (an abnormal formation of the pulmonary veins)

Children often have murmurs that are a normal part of development and do not require treatment. These murmurs include:

• Still's murmur
• venous hum
• pulmonary flow murmurs

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