Heart Murmur

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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Daniel Lee Kulick, MD, FACC, FSCAI

Daniel Lee Kulick, MD, FACC, FSCAI

Dr. Kulick received his undergraduate and medical degrees from the University of Southern California, School of Medicine. He performed his residency in internal medicine at the Harbor-University of California Los Angeles Medical Center and a fellowship in the section of cardiology at the Los Angeles County-University of Southern California Medical Center. He is board certified in Internal Medicine and Cardiology.

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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 heart beat to pump blood to the rest of the body.

How the heart works

• Each heart beat 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. Of note, not all heart murmurs are abnormal or dangerous, but if one is present it may signal a structural abnormality of the heart.