When a valve does not close tightly and blood leaks backward (regurgitation)
When blood flows through a narrowed or stiff heart valve (called stenosis)
There are several ways in which your doctor may describe a murmur:
Murmurs are classified ("graded") depending on how loud the murmur sounds with a stethoscope. The grading is on a scale. Grade I can barely be heard. An example of a murmur description is a "grade II/VI murmur." (This means the murmur is grade 2 on a scale of 1 - 6).
In addition, a murmur is described by the stage of the heartbeat when the murmur is heard. A heart murmur may be described as systolic or diastolic.
When a murmur is more prominent, the doctor may be able to feel it with the palm of the hand over the heart.
The doctor will take the following into consideration when examining you:
Does the murmur occur when the heart is resting or contracting?
Does it last throughout the heartbeat?
Does it change when you move?
Can it be heard in other parts of the chest, on the back, or in the neck?
Where is the murmur heard the loudest?
Many heart murmurs are harmless. These types of murmur are called innocent murmurs. They will not cause any symptoms or problems. Innocent murmurs do not need treatment.
Goldman L. Approach to the patient with possible cardiovascular disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24thed. Philadelphia, PA: Saunders Elsevier; 2011:chap 50.
Sabatine MS, Cannon CP. The history and physical examination:an evidence-based approach. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald'sHeart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 12.
Bonow RO, Carabello BA, Chatterjee K, de Leon AC Jr., Faxon DP, Freed MD, et al. 2006 Writing Committee Members; American College of Cardiology/American Heart Association Task Force. 2008 Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients with Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation. 2008;118:e523-e661.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.