Mitral valve prolapse: Normally our mitral valve closes completely when our left ventricle contracts, preventing blood from flowing back into our left atrium. If part of the valve balloons out so that the valve does not close properly, one have mitral valve prolapse. This causes a clicking sound as our heart beats. Often, this common condition is not serious. However, in rare cases it leads to infective endocarditis or mitral regurgitation (backward blood flow through the valve); both can be serious.
Mitral valve or aortic stenosis: Our mitral or aortic valves, both on the left side of our heart, can become narrowed by scarring from infections, such as rheumatic fever, or may be narrow at birth. Such narrowing or constriction is called stenosis. In mitral valve or aortic stenosis, the heart has to work harder to pump enough blood to satisfy your body's oxygen needs. If untreated, stenosis can wear out our heart and can lead to heart failure.
Aortic sclerosis: One in three elderly people have a heart murmur due to the scarring, thickening, or stiffening (sclerosis) of the aortic valve. This condition is generally not dangerous; typically, the valve can function for years after the murmur is detected. Aortic sclerosis is usually seen in people with atherosclerosis, or hardening of the arteries.
Mitral or aortic regurgitation: Regurgitation (backward flow) of blood can occur with mitral valve prolapse or mitral valve or aortic stenosis. To counteract this back flow, the heart must work harder to force blood through the damaged valve. Over time, this can weaken and/or enlarge the heart and can lead to heart failure.
Congenital heart defects: About 25,000 babies are born each year with heart defects, such as holes in heart walls or misshapen heart valves. Many congenital heart defects can be corrected by surgery.
Other Possible Causes of Heart Murmurs
Some common conditions can force your heart to beat faster, changing the rate and amount of blood moving through your heart and resulting in heart murmurs. You and your doctor should monitor all of these conditions:
· Pregnancy
· Anemia
· High blood pressure
· Overactive thyroid
· Fever
Parameters of a Murmur during examination:
§ Timing refers to whether the murmur is a systolic or diastolic murmur.
§ Shape refers to the intensity over time; murmurs can be crescendo, decrescendo or crescendo-decrescendo.
§ Location refers to where the heart murmur is usually auscultated best. There are six places on the anterior chest to listen for heart murmurs; each of the locations roughly corresponds to a specific part of the heart. The first five of the six locations are adjacent to the sternum. The six locations are:
the 2nd right intercostal space
the 2nd to 5th left intercostal spaces
the 5th left mid-clavicular intercostal space.
§ Radiation refers to where the sound of the murmur radiates. The general rule of thumb is that the sound radiates in the direction of the blood flow.
§ Intensity refers to the loudness of the murmur, and is graded on a scale from 0-6/6.
§ Pitch can be low, medium or high and is determined by whether it can be auscultated best with the bell or diaphragm of a stethoscope.
§ Quality refers to unusual characteristics of a murmur, such as blowing, harsh, rumbling or musical.
Grading of murmurs
Grade 1 Very faint
Grade 2 Soft
Grade 3 Heard all over the precordium
Grade 4 Loud, with palpable thrill (i.e. a tremor or vibration felt on palpation)
Grade 5 Very loud, with thrill. May be heard when stethoscope is partly off the chest.
Grade 6 Very loud, with thrill. May be heard with stethoscope entirely off the chest.
Tests for Heart Murmurs
Usually heart murmurs are detected during a physical exam. Your doctor will be able to hear your heart murmur when listening to your heart with a stethoscope.
Your doctor may order one or more of the following tests to see whether your heart murmur is innocent or whether it is caused by acquired valve disease or a congenital defect:
· Electrocardiogram (ECG), which measures the electrical activity of the heart
· Chest X-rays to see if the heart is enlarged due to heart or valve disease
· Echocardiography, which uses sound waves to map the heart structure
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