Tests and diagnosisBy Mayo Clinic staff
A doctor might first suspect hypertrophic cardiomyopathy if he or she hears a heart murmur while listening to the heart. A heart murmur could indicate that the thickened heart muscle is causing abnormal blood flow through the heart.
Echocardiogram is the most common test to diagnose hypertrophic cardiomyopathy. Using echocardiogram images, your doctor can see the thickness of your heart muscle, whether blood flow is obstructed and if your heart valves are moving normally.
An echocardiogram uses sound waves to produce images of the heart. An echocardiogram allows the doctor to see the complicated movement of the heart in motion — ventricles squeezing and relaxing, and valves opening and closing in rhythm with the heartbeat. The doctor can use these images to identify abnormalities in the heart muscle and valves. Types of echocardiograms include:
- Transthoracic echocardiogram. This is a standard echocardiogram. A technician (sonographer) spreads gel on your chest and then presses a device known as a transducer firmly against your skin, aiming an ultrasound beam through your chest to your heart. The transducer also detects sound wave echoes reflected by internal structures. A computer converts the echoes into moving images on a monitor. If your lungs or ribs obscure the view, a small amount of intravenous dye may be used to improve the images.
- Transesophageal echocardiogram. In this type of echocardiogram, a flexible tube containing a transducer is guided down your throat and into your esophagus, which connects your mouth to your stomach. From there, the transducer can get more-detailed images of your heart. Your doctor might order a transesophageal echocardiogram if it's difficult to get a clear picture of your heart with a standard echocardiogram or if he or she wants to further examine your mitral valve.
Additional tests might be done to help look for other effects of hypertrophic cardiomyopathy and help determine what sort of treatment could be needed. These additional tests include:
- Electrocardiogram (ECG). This test records the electrical activity of your heart. It's done to detect abnormal electrical signals that may result from the thickened heart muscle.
- Holter monitor. This is a portable ECG that records a continuous electrocardiogram of your heart, usually over the course of one to two days. It's used to detect abnormal heart rhythms.
- Cardiac catheterization. Sometimes your doctor may use this test to measure the pressure of blood flow inside your heart. A catheter is inserted into an artery, starting in your groin area. It's then carefully threaded to your heart chambers under guidance of an X-ray machine that shows real-time images of your body. Dye is injected through the catheter, and the X-ray machine makes images (angiograms) of your heart and blood vessels.
- Cardiac MRI. Cardiac magnetic resonance imaging (MRI) is an imaging technique that uses magnetic fields and radio waves to create images of your heart. Cardiac MRI is often used in addition to echocardiography, particularly if the echocardiographic images are not conclusive.
Testing approaches for first-degree relatives
Genetic tests are available that may be able to help your doctor diagnose hypertrophic cardiomyopathy. However, the genetic causes of hypertrophic cardiomyopathy aren't fully understood. More than 10 genes have been identified so far that can make you more susceptible to hypertrophic cardiomyopathy.
Because of the complex nature of how your genes interact, genetic tests often don't give a definitive answer. In addition, insurance companies may not cover the testing. Talk with your doctor about whether genetic testing could be an option for you.
If you have a first-degree relative — parent, sibling or child — with hypertrophic cardiomyopathy, experts recommend that you be screened regularly for signs of this condition starting at puberty (about age 12) or when you begin competitive athletics. The recommendation is to have an echocardiogram and electrocardiogram once each year until you reach adulthood (about age 18) and stop competitive athletics. If no evidence of hypertrophic cardiomyopathy is found by the time you reach adulthood, your doctor may recommend adjusting your screening schedule to once every five years.
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