Cardiomyopathy is a serious medical condition that centers on a weakened heart muscle. A group of disorders may result in cardiomyopathy by directly affecting the heart muscle's structure, function and pumping ability.
Cardiomyopathy appears in a variety of forms. Most commonly, it follows a heart attack or coronary artery disease, often in middle-aged men. Much more rarely, it shows up on basketball courts or football fields as young competitors with unsuspected cardiomyopathy are fatally stricken.
During pregnancy, a woman's cardiomyopathy symptoms can masquerade as normal effects of gestation. Broken heart syndrome, or takotsubo cardiomyopathy, sometimes results from severe physical or emotional stress. Cardiomyopathy can be temporary with complete recovery, but more typically becomes a chronic condition.
There may be no warning signs in early stages. As cardiomyopathy gradually worsens, you may have the following signs and symptoms:
Dilated cardiomyopathy. This most often occurs in adults ages 20 to 60, according to the American Heart Association. Heart attack, heart disease, high blood pressure and diabetes are among top causes. In some cases, the condition runs in families. In other cases, causes are unknown.
In dilated cardiomyopathy, the heart is weakened as the lower left ventricle – the primary pumping chamber – becomes stretched and thin, and eventually enlarged. As the problem spreads throughout the heart, it loses the ability to pump properly. Heart failure, heart valve problems, abnormal heart rhythms or arrhythmias and blood clot formation are possible complications.
Hypertrophic cardiomyopathy. This condition, which affects people of any age, typically runs in families. As many as 500,000 people in the U.S. have hypertrophic cardiomyopathy, according to the AHA. In hypertrophic cardiomyopathy, the ventricle walls become excessively thick and outward blood flow to the aorta may be blocked. In rare cases, the condition can trigger dangerous arrhythmias during extremely vigorous physical activity. Hypertrophic cardiomyopathy is the most common cause of sudden cardiac arrest in athletes, according to an overview study published in mid-2016.
Takotsubo cardiomyopathy (broken-heart syndrome). The condition, first identified in 1990, usually arises from severe stress that weakens the heart's left ventricle. It's been linked to emotional events and sudden spikes in stress hormones – such as when a beloved spouse dies or even by seemingly positive occurrences like surprise parties. Drops in hormones like estrogen may contribute to takotsubo cardiomyopathy, putting older women at higher risk after menopause. In rare cases takotsubo can be fatal.
Fortunately, takotsubo cardiomyopathy is usually nonlethal and temporary. "Most of the time it gets better," says Dr. Pamela Douglas, a professor of research in cardiovascular diseases at Duke University in Durham, North Carolina.
Peripartum cardiomyopathy. This develops during pregnancy or soon after. "It's a type of cardiomyopathy where the connection is pregnancy and we don't think there's some other cause," says Dr. Melinda Davis, a cardiologist at Michigan Medicine's Frankel Cardiovascular Center.
The condition can be confusing because symptoms of heart failure are often similar to those of normal pregnancy, says Davis, who is also an assistant professor at the University of Michigan. "Normally during pregnancy, women develop swelling and shortness of breath and it's very common," she says. "That's why (peripartum cardiomyopathy) can be difficult to diagnose and women sometimes don't get diagnosed right away." If the possibility of cardiomyopathy exists, she adds, a simple blood test called a BNP, which measures levels of a protein produced in the heart, can help screen women who need further evaluation.
Pregnancy affects how cardiomyopathy is treated. One of the key medication classes for cardiomyopathy, ACE inhibitors, cannot be taken during pregnancy, Davis notes. After delivery, she adds, "If a woman wants to breastfeed, there are certain ACE inhibitors that can be used, but women should talk to their doctors about it."
Some women recover completely from peripartum cardiomyopathy, whereas others have permanent heart failure and can be very sick, Davis says. "So it's important to have it diagnosed as soon as possible in order to be on the correct medications and to be monitored closely to see if the heart is getting better or worse after pregnancy."
Too often, Davis says, pregnant women say their symptoms have been dismissed when they felt something was wrong. "If women are concerned about their symptoms and having a lot of shortness of breath and swelling, they should be encouraged to talk to their doctor," she emphasizes.
An important issue in peripartum cardiomyopathy is whether a woman with this diagnosis can have another pregnancy. "The recommendation is that if the heart has not fully recovered, it's quite dangerous to have a subsequent pregnancy," Davis says. "If the heart muscle is completely recovered, then some women might get through another pregnancy. They may have recurrent symptoms of heart failure and the heart muscle could get weak again."
Any woman with a prior cardiomyopathy diagnosis should have a full consultation with a cardiologist before becoming pregnant, Davis says. "If they are already pregnant, they should be followed carefully with a cardiologist and high-risk obstetrician or maternal-fetal medicine specialist," she adds.
Restricted cardiomyopathy. In this rare form of cardiomyopathy, ventricle walls are overly rigid, preventing the heart from expanding properly during contractions.
Arrhythmogenic right ventricular cardiomyopathy. In ARVC, another rare form of cardiomyopathy, normal heart muscle tissue gradually dies and is replaced by scar and fatty tissue. Athletes are also vulnerable to this genetic form of cardiomyopathy, which can lead to dangerous arrhythmias and sudden death. Up to half of cases run in families, according to the Genetics Home Reference website, part of the National Institutes of Health.
Other causes. Certain viral infections and heavy alcohol use combined with malnutrition may also cause dilated cardiomyopathy, according to the Merck Manual.
Cardiomyopathy in children. Pediatric cardiomyopathy is rare, with slightly more than one in 100,000 children in the U.S. diagnosed each year, according to the Pediatric Cardiomyopathy Registry. Kids with cardiomyopathy and other childhood heart conditions should be followed by a pediatric cardiology team.
A physical examination and a thorough medical and family history are the first steps in cardiomyopathy diagnosis. Your physician will ask about symptoms and when they occur, such as while you're lying down or when you're exercising. Because cardiomyopathy can have a strong genetic connection, you may be asked about heart disease among your close relatives.
Tests you undergo would likely include a chest X-ray to detect heart enlargement, an echocardiogram to show images of your heart with ultrasound and an electrocardiogram, or EKG, to look for problems like abnormal heart rhythms.
Further testing could include more imaging tests such as a heart MRI or CT scan. More invasive testing with cardiac catheterization might be used to measure how strongly your heart pumps and to scrutinize for blood vessel blockages.
Medication. Two groups of medications called beta blockers and ACE inhibitors are primarily used to treat cardiomyopathy. "Those are very effective and they're mainstays," Douglas says. Medications help the body avoid overcompensating for heart dysfunction, she explains. Other types of drugs may also be used.
ACE inhibitors. Angiotensin-converting enzyme inhibitor medications like enalapril (Vasotec) widen blood vessels to increase blood flow in the heart.
Beta blockers. Medications such as metoprolol (Lopressor and Toprol XL) and carvedilol (Coreg) reduce the heart's workload and prevent further heart damage.
Diuretics. Diuretics, or "water pills" like furosemide (Lasix) help eliminate excess fluid that can cause shortness of breath and swelling.
Digoxin. In some types of cardiomyopathy, digoxin can strengthen the heart's ability to pump blood.
As you deal with this chronic condition, controlling heart risk factors is more important than ever, Douglas says. "So getting the blood pressure down, making sure the diabetes is well-controlled, stopping smoking," she says. "All the things we know you should be doing for your heart … it's not only to prevent heart disease but to manage it once you have it."
Exercise training can be helpful. "It gradually makes your muscles stronger and then your heart has to pump less hard for the same amount of exercise," Douglas says. Cardiac rehab programs, available in many medical centers nationwide, provide a safe, medically supervised way to gradually build your activity tolerance.
For those with cardiomyopathy complications or risks, heart devices may help.
People who are almost bedridden from late-stage heart failure might benefit from left ventricular assist devices, or LVADs. "These are implantable devices that take the blood out of the chamber of the heart and send it to the body with a mechanical oomph – instead of relying entirely on your ventricle's ability to pump," Douglas explains.
For some patients with cardiomyopathy who are at risk for sudden cardiac arrest, cardiologists may recommend a wearable, personal defibrillator called a LifeVest.
For cardiomyopathy patients with advanced heart failure, heart transplant is sometimes discussed as an option.
Once diagnosed with cardiomyopathy, you should receive ongoing care from a cardiologist. If you have a severe cardiomyopathy, you should be seeing a heart failure specialist, Douglas says.
"People (with cardiomyopathy) can carve a life out, perhaps with some limitations, but be able to enjoy many, many aspects of life," Douglas says. "It is a process. It's most likely a disease that patients will have for the rest of their life and will have to be managed in some way for the rest of their life. But it should be managed as a team."