Tests and diagnosisBy Mayo Clinic staff
Heart murmurs are usually detected when your doctor listens to your heart using a stethoscope during a physical exam.
To check whether the murmur is innocent or abnormal, your doctor will consider:
- How loud is it? This is rated on a scale from 1 to 6, with 6 being the loudest.
- Where in your heart is it? And can it be heard in your neck or back?
- What pitch is it? Is it high-, medium- or low-pitched?
- What affects the sound? If you change your body position or exercise, does it affect the sound?
- When does it occur, and for how long? If your murmur happens when your heart is filling with blood (diastolic murmur) or throughout the heartbeat (continuous murmur), that may mean you have a heart problem. You or your child will need more tests to find out what the problem is.
Your doctor will also look for other signs and symptoms of heart problems and ask about your medical history and whether other family members have had heart murmurs or other heart conditions.
If the doctor thinks the heart murmur is abnormal, you or your child may need additional tests including:
- Chest X-ray. A chest X-ray shows an image of your heart, lungs and blood vessels. It can reveal if your heart is enlarged, which may mean an underlying condition is causing your heart murmur.
- Electrocardiogram (ECG). In this noninvasive test, a technician will place probes on your chest that record the electrical impulses that make your heart beat. An ECG records these electrical signals and can help your doctor look for heart rhythm and structure problems.
Transthoracic or transesophageal echocardiogram. This exam, which includes an ultrasound of your chest, shows detailed images of your heart's structure and function. Ultrasound waves are transmitted, and their echoes are recorded with a device called a transducer that's held outside your body. A computer uses the information from the transducer to create moving images on a video monitor. This test identifies abnormal heart valves, such as those that are hardened (calcified) or leaking, and can also detect most heart defects.
If the images from a transthoracic echocardiogram are unclear, the doctor may recommend a transesophageal ultrasound. During this exam, a flexible tube containing a small transducer about the size of your index finger is guided down your throat. The transducer will transmit images of your heart to a computer monitor. Since the esophagus passes close behind your heart, the transesophageal transducer can produce better images than can sound waves transmitted through your chest.
- Cardiac catheterization. In this test, a short tube (sheath) is inserted into a vein or artery at the top of your leg (groin) or arm. A hollow, flexible and longer tube (guide catheter) is then inserted into the sheath. Aided by X-ray images on a monitor, your doctor threads the guide catheter through that artery until it reaches your heart. The pressures in your heart chambers can be measured, and dye can be injected. The dye can be seen on an X-ray, which helps your doctor see the blood flow through your heart, blood vessels and valves to check for problems. This test generally isn't necessary when diagnosing the cause of a heart murmur.
Cardiac computerized tomography (CT) or magnetic resonance imaging (MRI). These tests can help diagnose heart problems and detect heart murmurs. In a cardiac CT scan, you lie on a table inside a doughnut-shaped machine. An X-ray tube inside the machine rotates around your body and collects images of your heart and chest.
In a cardiac MRI, you lie on a table inside a long tube-like machine that produces a magnetic field. The magnetic field aligns atomic particles in some of your cells. When radio waves are broadcast toward these aligned particles, they produce signals that vary according to the type of tissue they are. Images of your heart are created from these signals, which your doctor will look at to determine the cause of your heart murmur.
- Chatterjee K. Auscultation of cardiac murmurs. http://www.uptodate.com/index. Accessed Feb. 8, 2012.
- Heart murmur. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/heartmurmur/printall-index.html. Accessed April 12, 2012.
- Furster V, et al., eds. Hurst's The Heart. 13th ed. New York, N.Y.: The McGraw-Hill Companies; 2011. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=5. Accessed Feb. 7, 2012.
- Frank JE, et al. Evaluation and management of heart murmurs in children. American Family Physician. 2011;84:793.
- Heart murmurs. American Heart Association. http://www.heart.org/HEARTORG/Conditions/More/CardiovascularConditionsofChildhood/Heart-Murmurs_UCM_314208_Article.jsp#.T4evW9Vr7To. Accessed April 13, 2012.
- Cardiovascular examination. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/cardiovascular_disorders/approach_to_the_cardiac_patient/cardiovascular_examination.html. Accessed April 13, 2012.
- Bonno RO, et al. 2008 Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease. Circulation. 2008;118:e523.
- Your guide to living well with heart disease. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/public/heart/other/your_guide/yg_livingwell.htm. Accessed April 13, 2012.
- Grogan M (expert opinion). Mayo Clinic, Rochester, Minn. May 1, 2012.