Hypertrophic cardiomyopathy is an inherited heart muscle disease. Medicine differentiates between an obstructive and a non-obstructive form. Patients of the non-obstructive form are often asymptomatic for a long time or even for life.
What is hypertrophic cardiomyopathy?
A quarter of patients suffer from heart muscle thickening of the left ventricle, which is located in the outflow tract. This creates an obstruction under stress, but also at rest.
The group of cardiomyopathies includes diseases of the heart muscle. Cardiomyopathies are associated with mechanical or electrical functional limitations of the heart. However, they do not necessarily have to be associated with pathologically altered heart chambers. Hypertrophic cardiomyopathy is also called hypertrophic familial cardiomyopathy. This condition is a congenital disease of the heart muscle. See AbbreviationFinder for abbreviations related to Hypertrophic Cardiomyopathy.
In addition to an asymmetric thickening of the left ventricle, the disease also causes the ventricles to widen. With a prevalence of 1:500, familial hypertrophic cardiomyopathy is a comparatively common heart disease. Inheritance takes place in the autosomal dominant mode. Two forms of heart disease are distinguished: hypertrophic cardiomyopathy with dynamic obstruction and a form without dynamic obstruction.
According to the World Health Organization (WHO) classification, all familial hypertrophic cardiomyopathies are classified as genetic primary cardiomyopathies. The disease was described by Liouville and Hallopeau in the mid-19th century. It has been recognized as a clinical entity since it was described by Brock in the 20th century.
Hypertrophic cardiomyopathies are genetically caused. More than 200 genetic defects in ten different genes are known to be possible causes. The causative genes all code for the proteins in the cardiac sarcomere. In more than 50 percent of cases, the genetic defect lies in the structure of the so-called beta-myosin heavy chain. The resulting structural changes in β-myosin and α-tropomyosin result from numerous point mutations in the structural proteins in the sarcomere, such as myosin-binding protein C or troponin-T.
Hypertrophic cardiomyopathy is therefore also called disease of the sarcomere. Most of the point mutations affect the gene locus MYH7 on chromosome 14. This leads to a branching disorder of hypertrophied heart muscle cells in the sarcomere. Due to increased lateral branching, the parallel arrangement is missing. The interstitium is remodeled with connective tissue. The phenotypic expression depends less on the individual mutation than on environmental factors and modifier genes. Up to the age of 13, the disease usually progresses silently.
Symptoms, Ailments & Signs
A quarter of patients suffer from heart muscle thickening of the left ventricle, which is located in the outflow tract. This creates an obstruction under stress, but also at rest. This results in an aortic stenosis with high pressure loads on the left ventricle. In about ten percent of patients, the obstruction is coventricular. Muscle thickening also causes muscle stiffness. The chambers of the heart only fill to a limited extent during the relaxation phase and blood backs up in the veins of the lungs, causing shortness of breath.
This phenomenon is known as diastolic heart failure. Muscle stiffening increases as the disease progresses as a result of the pumping effort. In the area of the narrowed outflow tract, a suction is created, which is also known as the Venturi effect. Leaks in the sense of mitral insufficiency often occur. Cardiac arrhythmias occur under stress, which can cause brief unconsciousness or even sudden cardiac death. Hypertrophic cardiomyopathy underlies many sudden deaths in young adults. Patients of the non-obstructive form are often asymptomatic. If symptoms are present, they are non-specific symptoms such as shortness of breath, dizzinessor angina pectoris.
Diagnosis & course of disease
When diagnosing hypertrophic cardiomyopathy, reactive myocardial hypertrophy due to sport (athlete’s heart) or high blood pressure must be ruled out. Diseases of the aortic valve must also be considered in the differential diagnosis. Physical examination of the patient reveals a systolic that increases with exercise. This symptom can be observed during the Valsalva maneuver.
The ECG ideally provides evidence of left ventricular hypertrophy by showing Q waves and a repolarization disorder. In addition to septal hypertrophy, echocardiography also shows a displacement of the mitral valve leaflet, which narrows the outflow tract. The resting gradient in the sense of a pressure jump between the left ventricle and the aorta is measured. Magnetic resonance imaging shows atypical forms of distribution and may show patchy scars in the myocardium.
In addition, the flow acceleration and possible indications of past septum embolizations can be displayed. A cardiac catheterization measures the pressure inside the heart to determine how stiff the heart muscle is. A molecular genetic examination secures the diagnosis. Many asymptomatic patients have a rather minor impairment and therefore a good prognosis. Forms with left ventricular outflow tract obstruction often progress to heart failure and therefore have a poorer prognosis.
Complications of hypertrophic cardiomyopathy arise from the possible symptoms and consequences. For example, cardiac arrhythmias can be dangerous. In this case, taking medication to treat the arrhythmia becomes necessary. In addition, the risk of sudden cardiac death, death from heart failure and stroke is comparatively high, which makes hypertrophic cardiomyopathy the most complicated and serious form of all cardiomyopathies.
Sudden cardiac death occurs in one percent of cases and tends to affect younger patients. Symptoms are usually mild, making it difficult to diagnose hypertrophic cardiomyopathy. It can also be observed that there is a higher risk for family members affected by the same disease. Heart failure, the most common complication, plays a greater role in older people.
Since the left outflow tract is increasingly being used, it can narrow as the disease progresses. This can cause the heart muscle to stiffen. A stiff ventricle results in atrial fibrillation, which affects 25 percent of those who have it. Endocarditis, an inflammation of the inner lining of the heart, can also occur as a secondary disease, which spreads to the heart valves.
Overall, hypertrophic cardiomyopathy is an incurable disease, which in most cases is free of complications and has good chances of treatment. Life expectancy is not affected, this is only the case with a severe course of the disease.
When should you go to the doctor?
Abnormal heart rhythms should be examined by a doctor. If there is a feeling of pressure in the upper body, an inner heaviness or breathing problems, a doctor is needed. Breathing disorders, shortness of breath or interruptions in breathing must be clarified immediately by a doctor. There is a risk of an undersupply of the organism, which can lead to multiple organ failure. Since hypertrophic cardiomyopathy can lead to sudden cardiac death without medical treatment, a doctor’s visit is recommended as soon as the first irregularities in cardiac activity occur.
If you experience tachycardia, high blood pressure, insomnia or inner restlessness, you should see a doctor. In the case of chest pain, reduced performance or rapid exhaustion, examinations must be initiated to clarify the cause. If disorders of consciousness set in or if unconsciousness occurs, the person concerned needs an emergency doctor. A rescue service must be alerted and first aid measures must be initiated. In the event of dizziness, unsteady gait or disturbances in attention, a visit to a doctor is recommended. A general feeling of illness or persistent malaise should be evaluated and treated. If the symptoms worsen, a visit to the doctor is essential. If the physical irregularities are accompanied by emotional problems, a doctor is needed.
Treatment & Therapy
Although hypertrophic cardiomyopathy has not yet been cured, it can now be treated symptomatically. The prognosis therefore improves the earlier the diagnosis is made. Drugs such as beta- blockers are available as conservative treatment measures to down-regulate the left ventricle of the heart. Antiarrhythmics reduce cardiac arrhythmias.
Patients are encouraged to avoid competitive sports and sports with sudden maximum exertion. Catheter treatment of the septal hypertrophy can be used as an interventional measure. This treatment is performed by transcoronary ablation of the septal hypertrophy or percutaneous transluminal septal myocardial ablation. The anterior interventricular ramus is closed with a balloon through a cardiac catheter. As the gradient in the outflow tract falls, pure alcohol is forced through the balloon and induces a localized infarction in the area of obstruction.
This reduces the obstruction. Another possible treatment option is endocardial radiofrequency ablation of septal hypertrophy. Cardiac catheter-guided radiofrequency ablation treats cardiac arrhythmias. Electrical energy is delivered to the right ventricle of the septum through a cardiac catheter in the area of the obstruction. Scarring reduces the gradient in the outflow tract of the left ventricle. One invasive treatment option is transaortic subvalvular myectomy.
This heart surgery removes muscle tissue from the outflow tract of the left ventricle through the aortic valve. Supportive measures are also available for patients with hypertrophic cardiomyopathy. For example, a defibrillator can be implanted to prevent cardiac arrhythmias.
Hypertrophic cardiomyopathy cannot be prevented because the disease has a genetic basis.
The follow-up options for hypertrophic cardiomyopathy focus primarily on the regular check-ups to ensure that the blood pressure is properly controlled. Depending on the symptoms, the doctor can expand this diagnosis or shorten the intervals between the examination appointments. In some cases, specialized doctors are available to patients who offer appropriate consultation hours.
In the long-term course of the aftercare, a stable course should take place, which the treating doctor is responsible for monitoring. If necessary, a new adjustment of the medication is necessary to avoid deterioration. However, in hereditary patients with an enlarged left ventricle, the risk of sudden cardiac death increases.
Those affected should refrain from excessive physical exertion and also exercise caution. If they overload themselves, the danger increases by leaps and bounds. If the physical exertion is unavoidable, patients should not stop abruptly, but let it fade away gradually. However, the usual everyday activities are generally not a problem and do not lead to complaints.
Those affected do not have to do without swimming, traveling and light activities. If other surgical or dental procedures are necessary, the doctor in charge must take the necessary precautions to protect the patient and minimize the risk.
You can do that yourself
In everyday life, the most important thing is to avoid situations that are physically demanding. Depending on the usual physical resilience of those affected, intensive sporting activities and competitive situations such as a soccer game or engaging in top-class sports may be included. Heavy physical work should also be avoided. This applies in particular if these are associated with strong pressing and pushing.
However, should a physically stressful situation arise, it is best not to end it abruptly, but to let it come to an end slowly. However, most everyday activities, but also traveling or swimming, are quite possible for those affected who are otherwise symptom-free. Sexual activities within a normal framework are unproblematic with normal everyday stress.
In order to prevent the development of further heart diseases, those affected should refrain from smoking. It is also recommended to eat a diet rich in vegetables and fruit and to eat only small amounts of cholesterol-containing foods with animal fats and meat. All stress factors should also be reduced. Those affected can also find help in self-help groups and Internet forums.