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Heart Murmur Symptoms, Causes, Treatments, and Surgery

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Heart murmur definition and facts

  • Heart murmurs are abnormal sounds within the heart due to turbulent blood flow.
  • Most murmurs are functional, or physiologic, and are normal variants. They are often known as innocent murmurs.
  • Some murmurs are due to abnormal function of the valves in the heart. The valves may have narrowing (stenosis) or they may leak (regurgitation).
  • Holes in the septum or wall that divides the atrium or ventricles (septal defects) may cause a murmur.
  • A murmur is a physical finding and not a structural problem within the heart itself. Treatment is aimed at the underlying condition.

What is a heart murmur?

A heart murmur is a continuous sound that is audible with a common stethoscope, produced when blood passes through particular areas of the heart. The heart has four chambers, two atria (singular = atrium) and two ventricles separated by a "skeleton" of cartilage that separates each chamber. This skeleton is made up of the atrial septum, the ventricular septum, and four valves (aortic, pulmonary, mitral, and tricuspid) that direct blood flow in a specific route within the heart allowing the most efficient use of each heartbeat to pump blood to the rest of the body.

How the heart works

  • Each heartbeat has two phases, systole when the heart pumps and diastole when the heart chambers fill with blood.
  • Blood enters the right atrium from the body via the vena cava.
  • It travels through the tricuspid valve into the right ventricle.
  • A systolic heartbeat sends the blood through the pulmonary valve, which separates the right ventricle and the pulmonary artery, to the lung.
  • In the lung, oxygen is delivered to red blood cells and carbon dioxide, a waste product of metabolism, is removed.
  • The oxygenated blood returns to the left atrium where it travels through the mitral valve into the left ventricle.
  • The systolic heartbeat also causes the left side of the heart to contract and send the blood through the aortic valve that separates the left ventricle and the aorta.
  • Blood passes through the aorta to the body delivering oxygen to the body's tissues.

The sound of a murmur is generated when blood flow within the heart is not smooth and turbulence occurs. Using a stethoscope, a health care practitioner may be able to hear a heart murmur during the physical examination. Not all heart murmurs are abnormal or dangerous and may be innocent, but if one is present it may potentially signal a structural abnormality of the heart.

Picture of the heart and heart valves.
Picture of the heart and heart valves.
Medically Reviewed by a Doctor on 11/13/2017


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