The term “cardiomyopathy” stands for various diseases of the heart muscle. In all forms, the muscle tissue changes its structure and loses its efficiency. Those affected often have the symptoms of heart failure. In the worst case, heart muscle disease can even trigger a sudden cardiac death. Learn here about the different forms of cardiomyopathy, what causes they have and what you can do about it.
With the term “cardiomyopathy” medical professionals summarize various diseases of the heart muscle (myocardium), which are associated with a dysfunction of the heart.
What happens with cardiomyopathy?
The heart is a powerful muscle pump that keeps the circulation going by constantly sucking and expelling blood.
The oxygenated blood from the body passes through the right atrium into the right ventricle. This pumps the blood into the lungs, where it is enriched with fresh oxygen. From there it flows via the left atrium into the left ventricle, which finally pumps the blood into the systemic circulation. Between the atria and the ventricles are the heart valves, which function like valves.
An essential feature of all cardiomyopathies is that the structure of the heart muscle continues to change during the course of the disease. This limits the pumping function of the heart. This leads to different complaints, depending on which form of cardiomyopathy is present and how pronounced it is.
Which cardiomyopathies are there?
Basically, doctors distinguish primary from secondary cardiomyopathies. Primary cardiomyopathy develops directly on the heart muscle and is restricted to it. In a secondary cardiomyopathy, however, the cause is a previous or existing, other disease, in the course of which the heart is damaged.
Primary cardiomyopathy may be present from birth, or acquired, that is, occur during the course of life. Also mixed forms of congenital and acquired heart muscle diseases are possible.
Based on the functional and structural changes of the heart muscle, cardiomyopathy can be divided into four main types. These are:
- dilated cardiomyopathy
- hypertrophic cardiomyopathy
- the restrictive cardiomyopathy
- arrhythmogenic right ventricular cardiomyopathy (ARVC)
Among cardiomyopathies, the dilated form is very common. The heart loses strength because of overstretching of the heart muscle. Read all about the text Dilated Cardiomyopathy!
In this type of cardiomyopathy, the heart muscle is too thick and its extensibility is limited. Learn all about this form of heart muscle disease in the text Hypertrophic Cardiomyopathy!
Restrictive cardiomyopathy is very rare. This stiffen the ventricular walls, because more connective tissue is incorporated into the muscle. The muscle walls are thus less mobile, which hinders especially the diastole, the phase in which the heart chambers fill with blood and expand.
This lowers the pumping power of the heart, although the ejection phase (systole) is usually not affected. The heart is usually normal in a restrictive cardiomyopathy, or slightly smaller.
Arrhythmogenic right ventricular cardiomyopathy (ARVC)
In ARVC, only the muscles of the right ventricle are altered. The muscle cells partially die and are replaced by adipose tissue. As a result, the heart muscle thins out and the right ventricle expands. Since this also affects the electrical conduction system of the heart, cardiac arrhythmias can occur, which occur especially during physical exertion.
In addition to the four main forms, there are other heart muscle diseases. These include non-compaction cardiomyopathy, which affects only the left ventricle, and broken-heart syndrome (Tako-Tsubo cardiomyopathy).
There is also the term “hypertensive cardiomyopathy”. This is sometimes referred to as a heart muscle disorder that occurs as a result of high blood pressure (hypertension). Because of the higher resistance in the arteries, the heart needs to pump more vigorously in hypertensive patients. Above all, the left ventricle therefore increases in volume and loses performance over time.
In the narrower sense, one counts for a high blood pressure induced dysfunction of the heart but not to the cardiomyopathy. Because, according to the American Heart Association’s (AHA) standard, cardiac muscle damage, which is a direct result of other cardiovascular diseases, must be distinguished from actual cardiomyopathy.
This form of cardiomyopathy is triggered by strong emotional or physical stress and usually heals without consequences. Read the most important information about broken-heart-syndrome here.
Who is affected by cardiomyopathy?
In principle, cardiomyopathy can affect anyone. However, it is not possible to make a general statement about the typical age of onset or gender distribution. Because these values are highly dependent on the particular form of cardiomyopathy.
For example, many primary cardiomyopathies are congenital and can be noticeable at an early age. Other, mostly secondary forms of heart muscle disease, however, occur later. Similarly, some types of cardiomyopathy affect more men, while there are also variants that occur mainly in women.
In all forms of cardiomyopathy, the heart is restricted in its pumping function, which is why many sufferers feel the typical symptoms of heart failure (heart failure):
The heart is no longer strong enough to pump enough blood into the arteries (forward failure). Patients often suffer from fatigue and weakness, and their performance decreases. The skin and mucous membranes sometimes appear bluish (cyanosis) in the case of severe heart failure, which is related to increased oxygen depletion.
Because of the pumping weakness of the heart, blood also accumulates in the lungs and veins (backward failure). The result is fluid retention in the lungs and body tissues called edema. Arm and leg edema are painless swelling under the skin. Pulmonary edema may be associated with coughing and life-threatening respiratory distress. The symptoms of backward heart failure are also called “stasis signs.”
In order to provide the body with sufficient oxygen despite the reduced ejection capacity of the heart chambers, the heart beats faster. Many patients with cardiomyopathy therefore have an increased heart rate (tachycardia). In addition, the structural changes in the heart muscle often lead to cardiac arrhythmia, which sometimes perceive those affected as heart stumbling. In case of severe cardiac arrhythmias, syncope may be synonymous with short fainting.
Depending on the type of cardiomyopathy, the symptoms mentioned may be different. Also, how long it takes until it even comes to complaints, depends heavily on the type of heart muscle disease. It happens again and again that a cardiomyopathy goes unnoticed for many years.
The arrhythmogenic right ventricular cardiomyopathy is often characterized by a pronounced tachycardia, which occurs especially under physical stress. Also syncope occur more often in this variant. Restrictive cardiomyopathy is more likely to be cardiac insufficiency with shortness of breath and congestion.
In patients with cardiomyopathy, blood clots form more easily on the inner heart walls than in healthy people. The reason is the uneven flow of blood in the heart because of the disturbed pumping function. When such clots break loose, they can occlude arteries in other organs or other body tissue. A feared consequence is, for example, lung infarction or strokes.
When the heart muscle changes, it often has an effect on the heart valves. For example, in the course of cardiomyopathy, valve defects such as mitral valve insufficiency may occur, which additionally disturb the pumping function of the heart.
In rare cases cardiac arrhythmias in the context of cardiomyopathy suddenly become so massive that the bloodstream collapses. This is the case, for example, when the heart chambers beat so fast that they can barely fill with blood between beats (ventricular tachycardia). Without immediate treatment, the result is sudden cardiac death.
Cardiomyopathy: causes and risk factors
Regarding the causes of cardiomyopathies, it makes sense to consider the primary ones as separate from the secondary forms of the disease.
Causes of primary cardiomyopathies
Primary cardiomyopathies often have genetic causes. The persons affected thus have a familial predisposition for a heart muscle disease, which can be different pronounced.
So there are variants that are likely to be inherited to the next generation within a family. In others, there is only one predisposition for the offspring, ie an increased risk of self-sufficiency. Cardiomyopathies with a genetic cause are often present from birth, but may also show up in the course of life.
Often the cause of a primary myocardial disease is unknown. This is called idiopathic cardiomyopathy. For example, in many patients with restrictive cardiomyopathy, no cause for the disease can be found.
Causes of secondary cardiomyopathies
There are numerous diseases that can damage the heart in addition to other organs and thus cause cardiomyopathy. Also, some drugs are among the possible triggers of heart muscle disease.
Secondarily induced cardiomyopathies are usually dilated or restrictive forms. The causes of restrictive cardiomyopathy include, for example:
- Diseases in which the connective tissue changes abnormally (scleroderma, sarcoidosis) or in which certain substances accumulate in the myocardium (amyloidosis, hemochromatosis)
- Tumors and inflammation
- repeated pericardial effusions
- radioactive radiation as part of radiotherapy
- Infection with mumps viruses during childbirth. Restrictive cardiomyopathy may also occur in affected children years after birth.
- Inflammation of the inner skin of the heart due to a pathological proliferation of certain immune cells (spoonbill endocarditis).
Also for a dilated cardiomyopathy, there are many possible causes, more in the corresponding text.
Cardiomyopathy: examination and diagnosis
As soon as the suspicion of cardiomyopathy arises, the disease must be proven and other causes excluded. There are various methods of investigation available.
Medical history and physical examination
First, it is important to ask the patient about his medical history. What are the complaints? When do you appear? How long have you been there? Because of the hereditary component of many cardiomyopathies, the doctor is particularly interested in whether similar cases are known in close relation (family history).
During the physical examination, the examiner pays attention to various signs that are common in cardiomyopathy. Sometimes listening to the heart provides more information. Also, certain blood levels help in the assessment of a possible heart damage.
Of particular importance in the investigation of cardiomyopathy is the use of special medical devices. This includes:
- Ultrasonic examination of heart (echocardiography) by means of which it is possible to establish thickness and mobility of a myocardium. Also, how much blood from the left ventricle is pumped into the systemic circulation, can be measured with this technique.
- an electrocardiogram (ECG) that records the electrical activity of the heart and records lead delays or any arrhythmias. Such a measurement is also possible over a longer period of time (long-term ECG) or under stress (stress ECG).
- a cardiac catheterization. The doctor pushes a thin plastic tube into the heart via a tube. Via the hose he can make various measurements, e.g. which pressures prevail in the different heart sections and the blood vessels close to the heart.
- a biopsy of the heart muscle. As part of the cardiac catheterization, you can also remove a small piece of the heart muscle and then look under the microscope. This may reveal how the structure of the heart muscle has changed.
- The representation of the heart with the help of X-ray images and CT images. X-ray images can only provide a rough overview, while computed tomography (CT) allows the heart to be displayed in detail. In certain cases, magnetic resonance imaging (MRI or MRI) is also used.
In some forms of cardiomyopathy, genes are known whose alteration causes the disease. Special genetic tests can be used to examine a patient for such mutations.
Ideally, treatment for cardiomyopathy will address the cause of the disease. One then speaks of a causal therapy. Often the triggering factors are not known or can not be treated. In such cases, one can only try to relieve the symptoms (symptomatic therapy).
Causal therapy of cardiomyopathy
A causal therapy of cardiomyopathy may be, for example, the use of drugs that inhibit inflammation or autoimmune reactions. If certain viruses are the cause of cardiomyopathy, they try to fight it. The pathological storage of certain substances in the heart muscle can possibly be slowed down with appropriate active ingredients.
Symptomatic therapy of cardiomyopathy
In the treatment of heart muscle disease, the focus is usually on relieving symptoms and preventing possible complications. Important is:
- to treat the effects of heart failure. For this purpose, one uses various medications such as diuretics, ACE inhibitors or beta-blockers, which should relieve the heart.
- to prevent possible arrhythmia. Also for this there are appropriate drugs, called antiarrhythmic drugs.
- to prevent the formation of blood clots in the heart. For this, the patients must regularly take anticoagulant drugs.
- physical conservation. Patients with cardiomyopathy avoid intensive physical stress, but regular exercise in moderation is certainly beneficial.
Depending on the form and stage of cardiomyopathy, surgical interventions may be considered for treatment. It removes, for example, parts of the heart muscle, or uses a pacemaker. As a last resort, when other treatments stop helping, all that remains is a heart transplant.
Cardiomyopathy: disease course and prognosis
Cardiomyopathies are usually serious illnesses. It is rarely possible to cure them and in many cases the health of those affected deteriorates steadily. A blanket statement on life expectancy is not possible. The prognosis depends strongly on the type and stage of heart muscle disease.
While patients with mildly pronounced hypertrophic cardiomyopathy have a near-normal life expectancy, dilated and restrictive cardiomyopathy are far worse off. Without heart transplantation, a large proportion of patients die in the first decade after diagnosis.
Arrhythmogenic right ventricular cardiomyopathy also has no good prognosis. Without therapy, about 70 percent of those affected die in the first ten years after diagnosis. But if it is possible to suppress the arrhythmia, the life expectancy is hardly limited in this form.
Sometimes one turns cardiomyopathy For a lifetime, little or no noticeable, but there is always a certain risk that dangerous cardiac arrhythmias occur.