What causes heart murmurs? 4 possible conditions
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During a regular medical checkup, your doctor will use a stethoscope to listen to your heartbeat to determine whether your heart is beating properly and has a normal rhythm. This gives the doctor information concerning the health of your heart. If your doctor hears a “murmur” or any other abnormal sounds coming from your heart, it may be an early indicator of a serious heart condition.
A normal heartbeat has two sounds, a lub (sometimes called S1), and a dub (S2). These are caused by the closing of valves inside the heart. If there are problems in the heart, there may be additional sounds or abnormal sounds.
Your doctor will listen to your heart with a stethoscope (a medical device used for listening (auscultation) to the heart, lungs, and other organs of the human body). If problems are detected, your doctor may order an echocardiogram (a test that uses sound waves to create a moving picture of the heart) to get a better understanding of the abnormal sounds detected.
The most common abnormal heart sound is a heart murmur. A murmur is a blowing, whooshing, or rasping sound that occurs during a heartbeat. There are two kinds of heart murmurs, innocent (also called physiological) and abnormal murmurs.
An innocent murmur is found in children, and is due to small holes between the different chambers of the heart. This usually does not cause significant problems, but may need to be monitored over time. An abnormal murmur in a child is due to congenital (present at birth) heart malformations, and may need to be corrected with surgery.
An adult abnormal murmur is usually due to problems with the valves that separate the chambers of the heart. If a valve does not close tightly and some blood leaks backward, this is called regurgitation. If a valve has become too narrow or becomes stiff, known as stenosis, it can also cause a murmur.
Murmurs are graded depending on how loud the sound is. The scale for grading is from one to six, where a one is very faint and a six is very loud—so loud it may not need a stethoscope to be heard. Murmurs are also categorized as occurring either during the first sound (S1) as systole murmurs, or during the second sound (S2) as diastole murmurs.
Other heart sounds include a “galloping” rhythm, with the occurrence of additional heart sounds S3 and S4. An S3 gallop or “third heart sound” is a sound that occurs after the diastole, S2 “dub” sound. In young athletes or pregnant women, it is likely to be harmless, but in older adults, it may indicate heart disease.
An S4 gallop is an extra sound before the S1 systole “lub” sound. This is always a sign of disease, likely the failure of the left ventricle of the heart. You may also have both an S3 and an S4 sound, and this is called a “summation gallop” when the heart is beating very fast. A summation gallop is very rare.
Clicks or short, high-pitched sounds may also be heard during the regular heartbeat. This could indicate a mitral valve prolapse, when one or both flaps of the mitral valve are too long. This can cause some regurgitation of blood into the left atrium.
Rubbing sounds may be heard in patients with certain kinds of infections. A rubbing sound is usually caused by an infection in the pericardium due to a virus, bacteria, or fungus.
If your doctor finds any abnormal heart sounds, he or she may ask you questions about your family. If any of your family members also have abnormal heart sounds or have a history of heart problems, it is important to tell your doctor. It may make diagnosing the cause of your abnormal heart sounds easier.
You doctor will also ask if you’ve had any other symptoms, such as bluish skin, chest pain, fainting, distended neck veins, shortness of breath, swelling, or weight gain. Your doctor may also listen to your lung sounds and see if you have signs of liver enlargement. These symptoms may provide clues about what type of heart problem you are experiencing.
The heart is made up of four chambers. The two upper chambers are called the atria and the two lower chambers are called the ventricles. Valves are located between these chambers to make sure that blood always flows in one direction.
The tricuspid valve goes from the right atrium to the right ventricle. The mitral valve leads from the left atrium to the left ventricle. The pulmonary valve goes from the right ventricle out to the pulmonary trunk, and the aortic valve goes from the left ventricle to the aorta. The pericardial sac surrounds the heart and protects it. Problems with these parts of the heart may lead to unusual sounds that can be detected by listening with a stethoscope or by performing an echocardiogram test.
Murmurs, especially in children, may be caused by congenital (present at birth) heart malformations. These can be benign and never cause symptoms or can be severe malformations that require surgery or even a heart transplant. Innocent murmurs include pulmonary flow murmurs, Still’s murmur, and a venous hum.
One of the more serious congenital problems that is a cause of heart murmurs is called the “Tetralogy of Fallot”. This is a set of four defects in the heart that lead to episodes of cyanosis. Cyanosis is when the skin of an infant or child turns blue from lack of oxygen during activity (like crying or feeding).
Another heart problem that causes a murmur is patent ductus arteriosus, in which a connection between the aorta and the pulmonary artery fails to close correctly after birth. Other congenital problems include atrial septal defect, coarctation of the aorta, and ventricular septal defect.
Heart Valve Defects
In adults, murmurs are usually the result of problems with the heart valves. This may be caused by an infection, such as endocarditis or infectious endocarditis. Valve problems can also simply occur as a part of the aging process due to wear and tear on the heart.
Regurgitation, or backflow, is when the valves do not close properly. The aortic valve can have aortic regurgitation. The mitral valve can have regurgitation, either acute (caused by a heart attack or a sudden infection) or chronic (caused by high blood pressure, infection, mitral valve prolapse, or other causes). The tricuspid valve can also suffer from regurgitation, usually caused by the enlargement (dilatation) of the right ventricle. Pulmonary regurgitation is caused by the backflow of blood into the right ventricle when the pulmonary valve cannot close completely.
Stenosis is a narrowing or stiffening of a valve. Mitral stenosis occurs most often due to rheumatic fever (a complication of untreated strep throat or scarlet fever). Mitral stenosis can cause fluid to back up into the lungs, causing pulmonary edema. Aortic stenosis can also occur because of rheumatic fever, and it may cause heart failure. Tricuspid stenosis can occur because of rheumatic fever or heart injury. Pulmonary valve stenosis is usually a congenital problem and runs in families. Aortic and tricuspid stenosis can also be congenital.
Another cause of heart murmurs is stenosis due to hypertrophic cardiomyopathy. The muscle of the heart thickens making it harder to pump blood through the heart. This results in a heart murmur. This is a very serious disease that is often passed on through families.
Causes of Clicks
Heart clicks are caused by problems with the mitral valve. Mitral valve prolapse is the most common cause, when one or both flaps of the mitral valve are too long. This can cause some regurgitation of blood into the left atrium.
Causes of Rubs
Heart rubs are caused by friction between layers of the pericardium—a sac around the heart. This is usually caused by an infection in the pericardium due to a virus, bacteria, or fungus.
Causes of Galloping Rhythms
A galloping rhythm of the heart, with a third or fourth heart sound, is very rare. An S3 sound is likely caused by an increased amount of blood within the ventricle. This may be harmless, but could indicate heart problems, such as congestive heart failure. An S4 sound is caused by blood being forced into a stiff left ventricle. This is a sign of serious heart disease.
Abnormal heart sounds often indicate some type of heart disease. This may be treated with medication, or may require surgery. It is important to follow up with a heart specialist and learn the details of your condition.
- Aortic Stenosis. (2012, June 4). National Center for Biotechnology Information.Retrieved July 31, 2012, from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001230/
- Explore Heart Murmur. (2010, August 1.) National Heart, Lung, and Blood Institute. Retrieved July 30, 2012, from http://www.nhlbi.nih.gov/health/health-topics/topics/heartmurmur/
- Grayzel, J. (1959). Gallop rhythm of the heart. Circulation, 20, 1053-1062. Retrieved July 30, 2012, from http://circ.ahajournals.org/content/20/6/1053
- Heart Murmurs and Other Sounds. (2010, June 5). National Library of Medicine - National Institutes of Health. Retrieved July 30, 2012, from http://www.nlm.nih.gov/medlineplus/ency/article/003266.htm
- Mitral Valve Prolapse. (2012, August). Texas Heart Institute at St Luke’s Episcopal Hospital. Retrieved July 31, 2012, from http://www.texasheartinstitute.org/hic/topics/cond/mvp.cfm
- Pericarditis. (2012, June 4). National Library of Medicine - National Institutes of Health. Retrieved July 31, 2012, from http://www.nlm.nih.gov/medlineplus/ency/article/000182.htm
- Waller, B. F. et al. (1995). Pathology of tricuspid valve stenosis and pure tricuspid regurgitation—part 1. Clinical Cardiology, 18(2), 97-102.Retrieved July 31, 2012, from http://www.ncbi.nlm.nih.gov/pubmed/7720297
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