You may know cardiomyopathy as a type of heart disease, but it’s actually more than that. Cardiomyopathy is really a group of diseases affecting the heart muscle. There are several kinds of cardiomyopathies, and each one has its own set of possible causes and outcomes.
One of the common characteristics of cardiomyopathies is that the heart muscle becomes bigger and sometimes weaker. In many cases, cardiomyopathy can lead to heart failure and possibly the need for a heart transplant. But depending on the type of cardiomyopathy they have (they may be mechanical or electrical problems), some individuals can live with the condition a long time.
Categorizing Cardiomyopathy Types
Some types of cardiomyopathy are acquired, while others affect those who are genetically predisposed to the condition. There are several classifications for cardiomyopathies. One way cardiomyopathies are categorized is as a primary or secondary cardiomyopathy.
Primary cardiomyopathy is a condition in which only the heart is involved. Some types of primary cardiomyopathy are passed from one generation to the next because of an abnormal gene. Secondary cardiomyopathy is a condition associated with multiorgan involvement including the heart. Examples include amyloidosis, sarcoidosis, and systemic lupus erythematosus. The treatment goal for secondary cardiomyopathies is to manage the underlying cause, as well as the heart manifestations.
Types of Cardiomyopathy
Understanding the nature of cardiomyopathies will be helpful if you or someone you know receives such a diagnosis. The following is a list of common and rare cardiomyopathies, as well as some details of these potentially serious diseases.
- Dilated cardiomyopathy: The ventricles (the heart’s two lower chambers) enlarge and then grow weaker. Dilated cardiomyopathy usually starts in the left ventricle, and can eventually affect the right one, too. The left ventricle pumps blood out through the aorta to the body. The right ventricle pumps blood out to the lungs to exchange carbon dioxide for oxygen. If the ventricles start to pump blood less effectively, the heart muscle works harder to meet the body’s demands for oxygenated blood. Over time, this causes the heart to weaken more, which can eventually result in heart failure—the inability of the heart to effectively pump enough blood to meet the body’s demand.
Dilated cardiomyopathy, experts say, is probably the most common cardiomyopathy worldwide. Some cases cause acute symptoms that require hospitalization and even advanced life support. Others may be chronic but stable. Causes can include infections, drugs, alcohol use, and gene mutations in up to 35 percent of cases.
Patients of dilated cardiomyopathy should usually be treated with beta blockers, and sometimes with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs), and sometimes diuretics, including spironolactone. A newer medication, Entresto, combines an ARB and a neprilysin inhibitor.
- Hypertrophic cardiomyopathy (HCM): HCM is associated with mutations in the heart muscle proteins (sarcomeres) in over half of cases. The ventricles and the septum (the wall separating the right and left sides of the heart) thicken. This may cause an obstruction that prevents blood from exiting the heart to the body. In addition to causing a stiffening of the ventricles, HCM can also cause mitral valve problems and changes in the cellular structure of the heart. These changes can lead to changes in the heart’s electrical activity and abnormal heart rhythms (arrhythmias).
- Arrhythmogenic right ventricle dysplasia (ARVD): This condition sometimes goes by other names, such as right ventricular cardiomyopathy and right ventricular dysplasia. It’s a rare condition that occurs when tissue in the right ventricle dies and is replaced with scar tissue. People with ARVD usually have an arrhythmia, which can raise the risk of sudden cardiac death, especially in young people.
ARVD often runs in families. It appears that certain gene abnormalities affect the proteins in the heart muscle, which eventually lead to ARVD.
Gene testing for cardiomyopathy is still in its early stages, and there are clinical trials going on now that could result in medications that can prevent the development of inherited cardiomyopathy.
Hypertrophic cardiomyopathy may yield, for some, few symptoms and may not preclude a normal life expectancy. Others may advance to a state where they have weakened hearts and must address heart failure, atrial fibrillation, or risk of sudden cardiac death.
First-line treatment for HCM is usually beta blockers and calcium channel blockers. Other medications may be needed to help control heart rate. Patients at risk for sudden cardiac death may also receive an implantable cardioverter defibrillator (ICD) to help control their arrhythmia.
Other Types of Cardiomyopathy
Among the least common types of cardiomyopathy is restrictive cardiomyopathy, which occurs when the walls of the ventricles become abnormally stiff and don’t have the flexibility to allow the chambers to fill with blood in between each heartbeat. As with most other forms of cardiomyopathy, heart failure is a likely outcome of restrictive cardiomyopathy.
There are other forms of cardiomyopathy, including chemotherapy-induced cardiomyopathy. This can occur when cancer-fighting drugs used during chemotherapy harm the heart muscle. A branch of medicine called cardio-oncology is designed to help patients receive effective cancer treatment while preserving heart function.
A cardio-oncologist is one of many types of doctors that treat cardiomyopathy. Some doctors specialize primarily in HCM, or in dilated cardiomyopathy, or any of the other forms of this disease.
One form of the condition, known as peripartum cardiomyopathy, develops during pregnancy. It’s a rare form of heart failure that is, fortunately, often reversible after the birth of the child. Many women who experience peripartum cardiomyopathy regain most if not all of their heart function. Also, a stress cardiomyopathy—referred to sometimes as broken heart syndrome—is triggered by emotional or physical stress and is more common in older women. Fortunately, this type of cardiomyopathy is also reversible.
While you can’t prevent inherited forms of cardiomyopathy, you can try to manage certain risk factors that might increase your odds of developing acquired types of the disease.
Even if you carry a gene for cardiomyopathy, you should still try to manage your blood pressure and cholesterol and control your alcohol consumption. A healthy diet and daily exercise are also advised for everyone, not just those at risk of a heart condition such as cardiomyopathy.