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What is cardiomyopathy?

In 1990, a 23-year-old in the prime of his college basketball career collapsed on the court in the middle of a game and was later pronounced dead due to hypertrophic cardiomyopathy. The death of the player, Hank Gathers, made headlines across the country. And it should have kick-started a push to better identify the genetic heart condition, which is a common cause of sudden cardiac arrest in young people, including young athletes, says Pim Suwannarat, MD, clinical geneticist at Mid-Atlantic Permanente Medical Group (MAPMG).

But unfortunately, awareness about hypertrophic cardiomyopathy, which affects one in 500 people and is caused by a genetic mutation, remains low. Today, many people who carry the mutation for it don’t know it, putting them at risk.

What is cardiomyopathy?

There are several different types of cardiomyopathy, but all cause the heart muscle to become enlarged, thick or rigid. In hypertrophic cardiomyopathy, one of the most common types in young people and the most common genetic heart condition, the thickening usually occurs in the lower left chamber of the heart. The thickening can hamper blood flow through the left ventricle, making the heart work harder.

How do you know if you or your child has hypertrophic cardiomyopathy?

The toughest part of diagnosing cardiomyopathy is that most people won’t have symptoms, particularly early on. A big warning sign is severe lightheadedness or passing out with exertion, such as when running or playing a sport. As the condition worsens, some people may experience shortness of breath that gets worse when laying down, swelling in the legs or feet, sudden and unexplained excessive weight gain, dizziness or light-headedness, chest pain, and/or heart palpitations.

“If you pushed on one of the swollen legs, there would be an indentation there,” says Emil Thattassery, MD, cardiologist at MAPMG. “And when I say unexplained, excessive weight gain, I mean 20 pounds over the last month, for example.” Contact your doctor if you or your child experience any of these symptoms. Your doctor can usually hear a loud heart murmur during an exam and may see abnormalities on an electrocardiogram, which tests the electrical activity of the heart.

If there is a concern, you’ll likely be referred to a cardiologist, who will perform an echocardiogram (an ultrasound that measures your heart beating and pumping) to determine if you have hypertrophic cardiomyopathy. A stress test may also be done.

“If you exercise regularly and notice a substantial change in your performance that seems unexplained, such as struggling to finish a run that was once routine, this could be a sign of hypertrophic cardiomyopathy,” says Dr. Suwannarat. But the condition can remain hidden until it results in sudden cardiac death, which is why it’s so important for children, especially those who play sports regularly, to undergo screening should you or a family member be diagnosed.

Genetic testing

If you have a family history of cardiomyopathy, specifically among first-degree relatives, genetic testing is often suggested to identify the condition before it causes problems. Children of a parent who has a genetic mutation for hypertrophic cardiomyopathy have a 50 percent chance of inheriting it. If someone in your family has been diagnosed with hypertrophic cardiomyopathy, there’s a good chance you could have it, too, notes Dr. Suwannarat. “Even if someone has just one person with hypertrophic cardiomyopathy in the family, I discuss genetic testing with them,” she says.

Be sure to tell your doctor about relatives who had a heart problem, even if it wasn’t diagnosed as cardiomyopathy, because in the past, the condition was sometimes misclassified, explains Dr. Suwannarat. “I’ve had patients who say a relative had a heart attack at a young age. But perhaps they really had cardiomyopathy,” she says. “It’s important to know if genetics are a factor for patients with this kind of history.”

If your doctor identifies that you as a good candidate for genetic testing, the next steps are fairly simple. Genetic tests are performed as blood tests. Samples are sent to a specialized lab that analyzes DNA genes of interest. “The lab will scan for panels of genes that are grouped based on cardiomyopathy types, then look at the genetic code to see if any letters are mixed up, kind of like running spellcheck,” says Dr. Suwannarat.

Not all of the genetic mutations that cause hypertrophic cardiomyopathy have been identified yet, so there are limits to what can be uncovered in genetic testing. “Sometimes, I have a patient who is diagnosed with hypertrophic cardiomyopathy, but their genetic testing comes back negative for the known mutations. This doesn’t mean there isn’t a genetic cause; it just means the particular mutation they have hasn’t been identified yet as a cause of cardiomyopathy,” notes Dr. Suwannarat.


Hypertrophic cardiomyopathy can’t be cured, so treatments are geared at relieving symptoms and preventing sudden cardiac death. Treatments vary depending on a number of factors, including the strength of your heart, your age, and other conditions. Beta blockers help the heart beat slower and with less force, and they can help lower blood pressure to improve blood flow. ACE inhibitors can help lower blood pressure and improve blood flow. Diuretics are sometimes prescribed; they help flush your system and get rid of unneeded water, making it easier for the heart to pump.

If medication doesn’t relieve symptoms, an implantable cardioverter defibrillator may be recommended. It keeps track of your heart rate and sends tiny electric shocks to your heart to stop any abnormal rhythm.

For those at risk of hypertrophic cardiomyopathy, it’s important to work with a cardiologist who has experience caring for patients with the condition. Dealing with it can seem daunting, but early detection and monitoring can go a long way toward helping you manage this condition – and even save your life.

Visit the American Heart Association’s website to learn more. For more information about the causes of heart attacks, visit MAPMG’s Staying Healthy pages.


Mid-Atlantic Permanente Medical Group, P.C. (Permanente) is our network of over 1,500 physicians who practice in our medical centers located in Maryland, the District of Columbia, and Virginia.