Hypertrophic cardiomyopathy (HCM)

2021-07-31 10:22 AM

Hypertrophic cardiomyopathy is usually caused by genetic mutations. These mutations cause the heart muscle to grow abnormally thick

Define

Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle becomes abnormally enlarged. Thickened heart muscle can make it harder for the heart to pump blood. Hypertrophic cardiomyopathy can also affect the electrical system of the heart.

Hypertrophic cardiomyopathy often goes undiagnosed because many people who have it have very few symptoms. In the few people who have this condition, the thickened heart muscle can cause signs and symptoms such as shortness of breath and problems in the heart's electrical system leading to life-threatening abnormal heart rhythms (arrhythmias). 

Fortunately, most people with hypertrophic cardiomyopathy lead normal lives, with no significant problems.

Symptoms

Possible signs and symptoms of hypertrophic cardiomyopathy include:

Shortness of breath, especially during exercise or exertion.

Chest pain, especially during exercise or exertion.

Fainting, especially during exercise or exertion.

Dizzy.

Tired.

Heart palpitations - feeling of the heart beating fast, fluttering, or palpitations.

Causes

Hypertrophic cardiomyopathy is usually caused by genetic mutations. These mutations cause the heart muscle to grow abnormally thick. People with hypertrophic cardiomyopathy also have an abnormal arrangement of heart muscle fibers. Cardiac muscle cells become cluttered, known as myofiber disorder. This mess can contribute to an irregular heartbeat (arrhythmia) in some people.

The severity of hypertrophic cardiomyopathy varies widely. Most people with hypertrophic cardiomyopathy have the walls between the two lower chambers of the heart (the ventricles) become thickened and obstruct blood flow. This is sometimes called obstructive hypertrophic cardiomyopathy. About 70 percent of people with hypertrophic cardiomyopathy have obstructive cardiomyopathy.

Sometimes hypertrophic cardiomyopathy occurs without significantly impeding blood flow. However, the left ventricular chamber itself can become stiff, reducing the amount of blood the ventricle can hold and be pumped out of the body with each contraction Doctors sometimes call this non-induced hypertrophic cardiomyopathy. obstructed or non-obstructive hypertrophic myocardium.

Risk factors

Hypertrophic cardiomyopathy is often inherited. There is a 50 percent chance that the children of people with hypertrophic cardiomyopathy will inherit the genetic mutation. Siblings of people with hypertrophic cardiomyopathy are also at risk. As a result, close relatives of patients with hypertrophic cardiomyopathy are encouraged to be screened for the disease.

Complications

Hypertrophic cardiomyopathy occurs in about one in 500 people and affects men and women equally.

In many people, hypertrophic cardiomyopathy does not cause significant health problems. However, in some people, hypertrophic cardiomyopathy can cause severe signs and symptoms such as shortness of breath, chest pain, or fainting.

People with hypertrophic cardiomyopathy are at risk for dangerously abnormal heart rhythms (arrhythmias), such as ventricular tachycardia or ventricular fibrillation. Abnormal heart rhythms can cause sudden cardiac death. Hypertrophic cardiomyopathy is the leading cause of sudden cardiac death in people under 30 years of age. Fortunately, such deaths are rare.

Possible complications of hypertrophic cardiomyopathy include:

Arrhythmia. Thickening of the heart muscle, as well as an abnormal structure of the heart cells (dysfunction), can disrupt the normal functioning of the heart's electrical system, resulting in a fast or irregular heartbeat. Atrial fibrillation, ventricular tachycardia, and ventricular fibrillation are among the arrhythmias that can be caused by hypertrophic cardiomyopathy.

The most feared complication of hypertrophic cardiomyopathy is sudden death from ventricular tachycardia or ventricular fibrillation. Unfortunately, it can be difficult to predict which people with hypertrophic cardiomyopathy are at more of the life-threatening risk. If you experience fainting spells, severe dizziness, or persistent palpitations, seek medical attention immediately.

Obstruction of blood flow. In many people, the thickened heart muscle impedes blood flow out of the heart. This can lead to exertional dyspnea, chest pain, dizziness, and fainting.

Mitral valve problem. The thickened heart muscle can leave a smaller space for blood to flow, which will cause blood to pass through the heart valves faster and harder. This increased force can prevent the mitral valve from closing properly. As a result, blood can leak back into the left atrium. This is called mitral regurgitation. An open mitral valve can lead to other complications such as heart failure or arrhythmias.

Heart failure. Heart failure is when the heart cannot pump enough blood to meet the body's needs. The thickened heart muscle of hypertrophic cardiomyopathy can eventually become too stiff to work effectively and can lead to shortness of breath and heart failure.

The heart muscle dilates. Over time, the thickened heart muscle can become weak and ineffective and the ventricles become dilated.

Tests and diagnostics

Your doctor may suspect hypertrophic cardiomyopathy if you hear a heart murmur while listening to your heart. A heart murmur may indicate thickening of the heart muscle causing abnormal flow.

Echocardiography is the most common test to diagnose hypertrophic cardiomyopathy. Using echocardiogram images, your doctor can see how thick your heart muscle is, if blood flow is obstructed and if your heart valves are moving normally.

An echocardiogram uses sound waves to create images of the heart. An echocardiogram allows the doctor to see the complex movement of the heart - the ventricles contract and relax, and the valves open and close. Doctors can use these images to identify abnormalities in the muscles and valves of the heart. Types of echocardiography include:

Transthoracic echocardiography. This is a standard echocardiogram. The transducer detects reverberation waves reflected by structures. A computer converts into moving images on the screen. If the lungs or ribs obscure vision, a small amount of intravenous dye may be used to improve the image.

Transesophageal echocardiography. A tube, containing an adapter, is guided down the throat and into the esophagus. From there, the transducer can get more detailed images of the heart. The doctor may order an esophageal echocardiogram if it is difficult to get a clear picture of the heart with standard echocardiography or if the person wants to consider adding a mitral valve.

Additional testing may be done to help find other effects of hypertrophic cardiomyopathy and to help determine what types of treatment may be needed. Additional tests include:

Electrocardiogram (ECG). This test records the electrical activity of the heart. It is done to detect abnormal electrical signals that may be the result of thickened heart muscles.

Holter followed. This is a handheld electrocardiogram that records electricity continuously in the heart, usually over the course of one to two days. It is used to detect abnormal heart rhythms.

Cardiac catheterization. Sometimes your doctor may use this test to measure blood flow pressure in your heart. A catheter is inserted into the artery, starting in the groin area. Then carefully thread to the cardiac compartment according to the radiograph's instructions. The dye is injected through the catheter, and the X-ray machine creates images of the heart and blood vessels.

MRI. Magnetic resonance imaging (MRI) is an imaging technique that uses a magnetic field and radio waves to create images of the heart. Cardiac MRI is often used after echocardiography, especially if the ultrasound images are inconclusive.

Experimenting with Relatives

Genetic testing is available, which may be able to help your doctor diagnose hypertrophic cardiomyopathy. However, the genetic cause of hypertrophic cardiomyopathy is not completely understood. There are more than 10 genes identified to date, which may predispose to hypertrophic cardiomyopathy.

Due to the complex nature of interacting genes, genetic tests often do not provide a definitive answer. Also, insurance companies do not cover these tests. Discussing with your doctor about genetic testing may be an option.

If there is a relative degree - a parent, sibling or child with hypertrophic cardiomyopathy, experts recommend regular check-ups for signs of the condition. For children, it is recommended to have echocardiography and electrocardiogram once a year until puberty or age 18. If no evidence of hypertrophic cardiomyopathy is found during adulthood If successful, your doctor may recommend adjusting your screening schedule every five years.

Treatments and drugs

The goals of treatment for hypertrophic cardiomyopathy are to relieve symptoms and prevent sudden cardiac death in high-risk individuals.

Optional treatment for an enlarged heart muscle includes medication, surgery, or other methods to destroy congested heart tissue or implanting devices to help control heart rhythm.

Treatment drugs. This is the best option for most people. Many medications can help relax muscles and slow the heart rate so it can pump more efficiently. Some medications your doctor may recommend include beta-blockers, calcium channel blockers, or the drugs disopyramide or amiodarone.

Partial removal of the septum muscle (myectomy). This is an open-heart operation in which the surgeon removes part of the thickened heart muscle, the wall that separates the two lower heart chambers (ventricles). Removing part of this muscle improves blood circulation and relieves mitral regurgitation. Myectomy is used if the medication does not relieve symptoms. Most people who have symptoms and undergo myectomy have no further symptoms. This surgery is only available at medical centers that specialize in treating hypertrophic cardiomyopathy.

Remove the septum. This is a new treatment in which a small part of the thickened heart muscle is destroyed by injecting alcohol through a catheter into an artery. There are possible complications with this procedure, including disruption of the heart's electrical system - necessitating the implantation of a pacemaker. The long-term success of this procedure is not known, but it is becoming increasingly popular.

Implant a pacemaker. A pacemaker is a small electrical device inserted under the skin that sends electrical signals to the heart to monitor and regulate the heartbeat. Pacemaker implant surgery is usually performed under local anesthesia and usually takes less than three hours. Pacemaker implantation is usually not as effective as the surgical option, but it is sometimes used in older adults who want to avoid many invasive procedures.

Subcutaneous implantable defibrillator (ICD). This is a device that is implanted in the chest like a pacemaker. The ICD continuously monitors the heart rate. If a life-threatening arrhythmia occurs, the ICD provides precisely calibrated electrical shocks to restore a normal heart rhythm. A small number of people with hypertrophic cardiomyopathy are at risk of sudden death from an irregular heartbeat. These individuals are at high risk, and many doctors recommend ICD implantation.

People with hypertrophic cardiomyopathy who may receive an ICD include those who:

There have been cardiac arrests.

One or more family members with sudden death from hypertrophic cardiomyopathy.

Fainting for no apparent reason.

Fast heart rate.

Blood pressure did not increase during the test exercise.

Echocardiography revealed extreme thickening of the left ventricular wall.

Coping and supporting

Being diagnosed with hypertrophic cardiomyopathy can cause a range of difficult emotions and fears. Like many people with this condition, there is the ability to struggle with emotions of fear, grief, and anger. These are the appropriate human responses to the severe changes that come with the diagnosis, including exercise limitations, lifelong drug dependence, fear of death, and fear of transmitting the conditions to the patient. children.

Not surprisingly, people with hypertrophic cardiomyopathy are at increased risk for mental health disorders, including depression, anxiety, and substance abuse problems. Talk to your doctor if you feel hopeless, panicked, or unable to cope. In some cases, it is possible to benefit from medical treatment for these mental health conditions. In other cases, mental health may benefit most from talking with health professionals, such as a health care team or genetic counselor, who can help understand the risks. risks and find ways to deal with them effectively.

Prevention

Because hypertrophic cardiomyopathy is inherited, it cannot be prevented. However, doctors and scientists are studying more about the genetic mutations that cause the disorders. Although the condition itself cannot be prevented, it is important to identify the condition as early as possible to guide treatment and prevent complications.

Prevention of sudden death

The use of implantable defibrillators has been used to help prevent sudden cardiac death but is rare in people with hypertrophic cardiomyopathy.

Unfortunately, because many people with hypertrophic cardiomyopathy don't realize they have it, there are cases where the first sign of a problem is sudden death. These cases can occur in seemingly healthy young people, including athletes, and active adults. News of all kinds of deaths is understandable because they are so unexpected, but it should be known that these deaths are not high.

However, cardiac specialists generally advise people with hypertrophic cardiomyopathy not to participate in most competitive sports, with the possible exception of some low-intensity sports. Talk to your cardiologist about specific recommendations. The use of an implantable defibrillator should not be seen as a substitute for these recommendations.