How Hypertrophic Cardiomyopathy Is Diagnosed

Your heart is a muscle. As Dr. Noah Moss, an advanced heart failure and transplant cardiologist at the Mount Sinai Foster Hospital in New York City, he says, “a very special muscle, but a muscle.”

Hypertrophic cardiomyopathy, or HCM, is a genetic disease in which the heart muscle grows thicker than normal. You might think of the term “big-hearted” to connote something good, says Dr. Matthew W. Martinez, director of Atlantic Health System Sports Cardiology at Morristown Medical Center in Morristown, NJ, and is a nationally recognized expert in HCM. But with this condition, “there is too much of a good thing, and that extra fat leads to the problems associated with this disease,” he explains. The heart is inefficient (it does not express enough blood), and the obstruction in the cavity of the heart leads to murmurs that can worsen with exercise, make you short of breath and create electrical changes in the heart.

Here’s what you need to know about how cardiologists diagnose the condition.

What is hypertrophic cardiomyopathy?

HCM can manifest in childhood, adolescence, or at any time in adulthood.

Doctors typically divide the condition into two forms: obstructive (oHCM) and non-obstructive (nHCM). The obstructive form, which accounts for about two-thirds of the healthy HCM population, occurs when the mitral valve moves abnormally, in a way that causes obstruction of blood flow between the heart and the aorta. “Both forms can cause shortness of breath, which worsens with exertion,” says Dr. Ronald Wharton, director of the hypertrophic cardiomyopathy program. Cardiovascular Institute, Northwell Health at North Shore University Hospital in Manhasset, NY “The obstructive form also causes vertigo that can be worsened with exercise, bending over, or a rapid change in position, [such as] get up quickly.”

Unfortunately, HCM often flies under the radar since its symptoms are not unique to the disease. “Not every patient has a murmur, and not every patient who has a murmur will have one when they’re sitting on an exam table,” says Wharton. “If efforts are not made to elicit the murmur – often the case in a busy office – the physical examination can easily miss the diagnosis.” (The most common way for doctors to elicit a murmur is the “Valsalva” maneuver, in which patients are asked to breathe while pinching their nose or asked to “bear as if having a bowel movement “).

HCM is important to diagnose in a timely manner to prevent the development of clinical manifestations of the disease, such as shortness of breath with walking, dizziness, or feeling of intense heartbeat, says Moss. Then, in rare cases – about 1% of those with HCM – the disease is associated with sudden cardiac death due to abnormal heart rhythms that cause the heart to stop beating effectively. (According to Martinez, the risk of sudden death from HCM may increase in certain groups, such as the young, those with a family history of sudden cardiac death, and those who have had heart MRI scans).

Read more: What to know about hypertrophic cardiomyopathy in children

If you’re a patient who has a very high risk of sudden cardiac death, Moss explains that your care team will recommend implanting a defibrillator, which is a device that continuously monitors the heart and can shock it out of a deadly arrhythmia if detects it. However, Martinez assures individuals that this is a disease with normal longevity. “Most people live well into their 80s with the disease,” he says. “Most people live a healthy life. You can still exercise, you can still participate in life, but you need to be seen [regularly by a cardiologist].”

HCM is typically diagnosed when evaluating the symptoms associated with the disease, or after an abnormal electrocardiogram (EKG). Typically, EKGs are administered during a routine wellness visit or to evaluate an HCM symptom, or during screening of family members of people with HCM, says Moss. (Screening of first-degree relatives – a person’s parent, sibling or child – is recommended after a family member is diagnosed with HCM).

The sooner you know you have HCM, the sooner you can start treatment. Seeing a cardiologist for regular check-ups is essential, experts agree, especially if a family member has the disease or you have shown symptoms associated with HCM.

Because it is not diagnosed

HCM affects about 1 in 250 to 1 in 500 people. Unfortunately, not everyone with HCM is aware of it, mainly because a large portion of those with HCM are asymptomatic. “About a million people in the United States carry the disease, but only 150,000 have a diagnosis. So that tells us about 85% of the time, it is missed,” says Martinez. “Hiding in plain sight.”

Symptoms such as shortness of breath, exercise intolerance and the feeling that your heart is racing can occur over a long period of time. That can lead to what Martinez calls “the onset of insidious disease.” “You say, ‘Hey, I’m just older.’ I’m out of shape. I don’t exercise that much. And you ignore it,” he says.

Wharton echoes this sentiment, noting that the data available They suggest that patients are often not diagnosed for three to five years after the onset of symptoms.

Echocardiogram

Echocardiograms, which are about 90% effective in finding HCM, are the first line standard when it comes to diagnosing the disease. While an abnormal EKG is often the first sign of HCM, doctors make the official HCM diagnosis out of an echocardiogram, often called an echo.

An echocardiogram is also the most practical way to diagnose HCM. “It is commonly available, provides information on structure and function, is relatively inexpensive, well tolerated, and performed without significant risk to the patient,” says Moss. After you’ve been diagnosed with HCM, echoes have the added benefit of helping doctors assess how you’re responding to treatment.

Read more: 9 strange symptoms cardiologists say you should never ignore

Adds Wharton: “[An echo] it is superb not only to assess the anatomy, but also to assess the changes in the pressures in the chambers of the heart”.

Think of an echo as an ultrasound of your heart. “It allows us to see deep through the chest wall and visualize the heart and the blood flow through it. We can measure the thickness of the heart muscle, see which area of ​​the heart is affected, and see if and how thickness affects the normal function of the heart,” explains Moss. The exam takes about 40 minutes while you lie on a table in a dark room with heart rate monitoring sensors attached to your chest. Then, a cardiac sonographer applies gel to your chest and uses a probe, called a transducer, that creates moving images of your heart and other structures in your chest. It doesn’t hurt: “All you feel is the cool gel on your chest and the pressure from the transducer,” says Moss.

Cardiovascular MRI

Cardiac magnetic resonance imaging, or a cardiovascular MRI, is another valuable tool for diagnosing HCM. After receiving an abnormal EKG, an echo is often the first line of evaluation for patients, but some people still need a cardiac MRI to confirm the diagnosis, Martinez says.

In general, a cardiac MRI usually confirms the diagnosis of HCM previously determined by an echocardiogram. “Its use is mainly to help assess the risk for dangerous cardiac rhythms. Sometimes it can also find other diagnoses of other conditions, often more rare, that can mask as HCM,” adds Wharton, as the cardiac amyloidosis and Danon’s disease.

Read more: How hypertrophic cardiomyopathy progresses in adults

“During the MRI, you lie on a bed that moves inside a tube-shaped scanner,” says Moss. “You need to sit still and hold your breath for some parts of the scan.” It is painless, but some patients may experience claustrophobia during the test, he says, noting that it can take up to 90 minutes to complete the study.

Why a Diagnosis Doesn’t Spell Doom

After a thorough evaluation, most of the time, symptom relief medications and monitoring help patients. Asymptomatic patients can usually start with just monitoring.

If you have recently been diagnosed with HCM, keep in mind that it should not stop you from leading a healthy and active life. In fact, in 2023, Martinez and his colleagues saw about 2,000 patients with HCM, some of whom were Division 1 college or professional athletes, including a number of NBA and NFL players.

“We have a lot of great results,” says Martinez. “My favorite thing to hear from patients when they leave the room [is]”I feel much better about this disease than when I came here.” And we literally do that every day.”