Your doctor may review your medical and family history, discuss your signs and symptoms, and conduct a physical examination. Your doctor may order several tests to diagnose hypertrophic cardiomyopathy (HCM).
Your doctor is likely to recommend an imaging test called an echocardiogram to diagnose hypertrophic cardiomyopathy. This test allows your doctor to see whether your heart muscle is abnormally thick, your blood flow is obstructed and your heart valves are moving normally.
Types of echocardiography include:
- Transthoracic echocardiogram. In this test, a device (transducer) is pressed firmly against your skin. The transducer aims an ultrasound beam through your chest to your heart, producing moving images of the working of the heart.
- Transesophageal echocardiogram. In a transesophageal echocardiogram, doctors guide a flexible tube containing a transducer down your throat and into the tube connecting your mouth and stomach (esophagus). From there, the transducer can obtain more-detailed images of your heart. This test may be recommended if it's difficult to get a clear picture of your heart with a standard echocardiogram or if the doctor wants to further examine your mitral valve. This test is done in very few people with hypertrophic cardiomyopathy.
Additional tests might be ordered to look for other effects of hypertrophic cardiomyopathy and help your doctor determine the most appropriate treatment for your condition. These additional tests include:
- Electrocardiogram (ECG). Wires (electrodes) attached to adhesive pads on your skin measure electrical impulses from your heart. An ECG can detect enlarged chambers of your heart and abnormal heart rhythms.
- Treadmill stress test. Your heart rhythm, blood pressure and breathing are monitored while you walk on a treadmill. Your doctor may recommend a treadmill stress test to evaluate symptoms, determine your exercise capacity, and determine if exercise provokes abnormal heart rhythms. Treadmill stress tests are sometimes performed with echocardiography if you have symptoms of HCM but a resting echocardiogram doesn't show obstructed blood flow. This test is commonly used in people with hypertrophic cardiomyopathy.
- Holter monitor. You may wear a portable ECG that records your heart's activity continuously over one to two days. This test is often done in people with hypertrophic cardiomyopathy.
- Cardiac MRI. A cardiac MRI uses magnetic fields and radio waves to create images of your heart. Cardiac MRI is often used in addition to echocardiography in the evaluation of people with hypertrophic cardiomyopathy.
- Cardiac catheterization. In this procedure, a catheter is inserted into a blood vessel, usually in your neck or groin area. The catheter is then carefully threaded to your heart chambers under guidance of an X-ray machine. In addition to measuring pressures in your heart, cardiac catheterization is used to obtain X-ray images (angiograms) of your heart and blood vessels. A dye is injected through the catheter to help visualize your heart and blood vessels. This test is rarely used to diagnose hypertrophic cardiomyopathy.
If you have a first-degree relative — parent, sibling or child — with hypertrophic cardiomyopathy, doctors may recommend that you be screened for the condition. Doctors will discuss with you the test results, and the risks and benefits of genetics tests. There are two types of screening:
Genetic testing. Genetic tests may not provide a definitive answer because the genetic causes of hypertrophic cardiomyopathy aren't fully understood. Only 50 to 60 percent of families with HCM have a currently detectable mutation, and some insurance companies may not cover genetic testing.
However, if an abnormal gene is detected in your family, then other family members can learn if they are at risk of hypertrophic cardiomyopathy through genetic testing. Consultation with a genetic counselor is recommended to help you determine whether genetic testing is a good option for you.
- Echocardiography. If genetic testing is not done, or if the results are not helpful, then your doctor may recommend echocardiography on a regular basis if you have a family member with hypertrophic cardiomyopathy. Adolescents and competitive athletes should be screened once a year. Adults who don't compete in athletics should be screened every five years.