What Is Dilated Cardiomyopathy?

Dilated cardiomyopathy (DCM) is an unexplained primary cardiomyopathy. The disease is characterized by enlarged left or right ventricles or bilateral ventricles, with impaired ventricular systolic function, with or without congestive heart failure. Ventricular or atrial arrhythmias are more common. The condition is progressive and death can occur at any stage of the disease.

Basic Information

nickname

Congestive cardiomyopathy

English name

dilated cardiomyopathy

Visiting department

Cardiology, Cardiac Surgery

Multiple groups

Middle-aged man

Common causes

Virus infection, cellular immunity, family inheritance, idiopathic

Common symptoms

Congestive heart failure is predominant, with shortness of breath and edema being the most common

Contagious

no

Causes of dilated cardiomyopathy

Infection

In animal experiments, the virus can not only cause viral myocarditis, but also cause lesions similar to dilated cardiomyopathy. In recent years, molecular biology techniques have been used to detect enterovirus or cytomegalovirus RNA in myocardial biopsies from patients with this disease. This shows that the disease is closely related to viral myocarditis.

2. Genes and autoimmunity

In the past, most cases of DCM were thought to be sporadic or idiopathic, but now it is found that at least 40% to 60% are familial. Pedigree analysis showed that most of the DCM families were autosomal dominant, and a few were autosomal recessive, mitochondrial, and X-linked. On the other hand, changes in the immune response can increase the susceptibility to disease, and can also cause myocardial autoimmune damage.

3. Cellular immunity

In patients with this disease, the natural killer cell activity is reduced, the defense ability of the body is reduced, and the number and function of suppressor T lymphocytes are reduced. As a result, a cell-mediated immune response occurs, causing vascular and myocardial damage.

Clinical manifestations of dilated cardiomyopathy

Mostly middle-aged people. Onset is usually slow, sometimes reaching more than 10 years. Symptoms are congestive heart failure, of which shortness of breath and edema are the most common. Shortness of breath initially after work or exertion, shortness of breath during mild activities or rest, or paroxysmal dyspnea at night. Patients often feel weak.

Physical examination showed that the heart rate accelerated, the apex beat shifted to the left and lower, there could be lifting beats, the heart dullness circle expanded to the left, and the third or fourth sound was often audible. Due to the enlargement of the heart cavity, there may be systolic whistle-like murmurs caused by relative mitral or tricuspid valve insufficiency. Such murmurs are alleviated after cardiac function is improved. In advanced cases, the blood pressure is reduced, the pulse pressure is small, and the diastolic blood pressure may be slightly increased when heart failure occurs. The presence of alternating pulses suggests left heart failure. Pulse is often weak.

There can be snoring sounds in both lungs during heart failure. In right heart failure, the liver is enlarged and the edema begins in the lower limbs. There may be pleural and abdominal effusions in the later stages, and various arrhythmias may occur. High atrioventricular block, ventricular fibrillation, and sinoatrial block can lead to Als-Si Has become one of the causes of death. In addition, there may be embolism in the brain, kidney and lung.

Dilated cardiomyopathy

1. X-ray inspection

The enlargement of the heart is prominent, with the left ventricular enlargement and the right ventricle enlargement. There may also be left atrial and right atrial enlargement.

2. ECG

Different degrees of atrioventricular block, right bundle branch block is common. Extensive ST-T changes, left ventricular high voltage, left atrial hypertrophy, pathological Q waves can occur due to myocardial fibrosis, and each lead has low voltage.

3. Echocardiography

The left ventricle was significantly enlarged, the left ventricular outflow tract was dilated, the ventricular septum and the amplitude of the left ventricular posterior wall weakened.

4.Isotopic inspection

Isotope myocardial perfusion imaging is mainly manifested by enlarged heart chambers, especially the bilateral ventricles. Myocardial imaging is said to be diffuse thinning.

5. Endocardial myocardial biopsy

The clinical manifestations and auxiliary examination of dilated cardiomyopathy lack specificity. In recent years, endocardial myocardial biopsy has been carried out at home and abroad. The diagnosis of this disease has higher sensitivity and lower specificity.

Dilated cardiomyopathy diagnosis

Dilated cardiomyopathy is an exclusionary diagnosis, which excludes the enlargement of the heart and cardiac insufficiency caused by other specific causes. The diagnosis can be made based on clinical manifestations and auxiliary examinations.

Dilated cardiomyopathy treatment

Treatment principle

(1) Maintain normal rest, use sedatives when necessary, and low-salt diet during heart failure;

(2) Prevention and treatment of arrhythmia and cardiac insufficiency;

(3) Anticoagulant therapy for those with a history of embolism;

(4) those who have a large amount of pleural effusion, for pleural puncture;

(5) Severe patients can consider artificial heart assist devices or heart transplantation, and can perform cardiac resynchronization therapy (CRT);

(6) symptomatic and supportive treatment;

2. Heart failure treatment

(1) It is important to emphasize rest and avoid fatigue. If the heart is enlarged and the heart function is reduced, more attention should be paid and long-term rest should be taken to prevent the condition from worsening.

(2) Cardiac drugs, diuretics and vasodilators are used in patients with heart failure. Due to the extensive myocardial damage, digitalis and diuretics are beneficial; hydrochlorothiazide may fail during low glomerular filtration. At this time, diuretics such as furosemide should be used. Vasodilators, such as angiotensin-converting enzyme inhibitors. Be sure to start with small doses, taking care to avoid hypotension. The use of beta-blockers when heart failure is stable is beneficial to improving the prognosis.

(3) Patients with arrhythmia, especially those with symptoms, need to be treated with antiarrhythmic drugs or electrical methods. Treatment of patients with rapid ventricular rhythm and high atrioventricular block at risk of sudden death should be active.

(4) Oral anticoagulants or antiplatelet aggregation drugs can be used to prevent embolic complications.

(5) For long-term heart failure, those who have failed medical treatment should consider heart transplantation, actively control infection after surgery, improve immunosuppression, and correct rejection. Survival rate can reach more than 85% after 1 year.

3. Precautions for medication

(1) Sensitivity to digitalis during myocardial disease, the application dose should be small, and pay attention to toxic reactions, or use non-cardioside positive inotropic drugs

(2) Pay attention to electrolyte balance during the application of diuretics;

(3) When using heart rate-inhibiting drugs or electrocardiac tachyarrhythmias, one should be alert to the possibility of sick sinus syndrome at the same time;

(4) Permanent artificial pacemaker can be installed in patients with chronic complete atrioventricular block and sick sinus syndrome;

(5) During the application of antiarrhythmic drugs, the ECG should be reviewed regularly;

(6) During the use of anticoagulants, pay attention to bleeding performance, and regularly check the clotting time, prothrombin time, and INR.

4. Special treatment

Heart transplantation for dilated cardiomyopathy can prolong life. After heart transplantation, the prognosis is greatly improved.