Disease introduction
Dilated cardiomyopathy is the most common kind of cardiomyopathy, which is mainly characterized by dysfunction of left ventricular or biventricular cavity enlargement and contraction, leading to congestive heart failure, often accompanied by arrhythmia.
The annual incidence of DCM is 5/100000 ~ 8/100000, and it is on the rise, with more males than females (2.5: 1), and the average onset age is about 40 years old. About14 heart failure in the United States is caused by DCM. The clinical manifestations of patients are different. Many patients with symptoms get worse, and 10%~ 15% patients have symptoms of heart failure within one year. The estimated annual mortality of patients with heart failure is 1 1%~ 13%. A few newly diagnosed DCM patients can relieve themselves.
Perhaps this disease represents the same manifestations of myocardial injury caused by many unknown harmful factors, and its etiology is still unclear. At present, there are three possible basic damage mechanisms:
⑴ Familial and hereditary factors: About 25%~30% of DCM patients carry genetically acquired pathogenic genes, and most familial cases are autosomal dominant. Familial DCM may be caused by mutations in genes encoding cytoskeleton, nuclear membrane or contractile proteins, including serine, myosin and troponin T.
⑵ Viral and other cytotoxic damage: Endocardial biopsy of some patients with clinical symptoms of DCM showed evidence of inflammatory myocarditis, and there was a hypothesis that subclinical viral myocarditis initiated autoimmune reaction and eventually developed into DCM. Other supporting evidence is that high titer of virus antibody, virus-specific RNA and obvious virus particles were found in patients with idiopathic DCM. Polymerase chain reaction (PCR) confirmed that there were virus residues in the myocardium of some patients with cardiomyopathy.
⑶ Immune abnormality: There are autoimmune abnormalities in DCM patients, including humoral immunity and cellular immunity, which are related to HLA)ⅱ class II molecules (especially DR4), suggesting that abnormal immune regulation may be one of the causes of DCM.
Dilated cardiomyopathy, four cardiac chambers are enlarged and dilated, and ventricular dilatation is more obvious than atrial dilatation. In patients with mild ventricular dilatation, the ventricular wall is slightly thickened, the lesion develops and the dilatation is aggravated, the ventricular wall is relatively thin, and the ventricular wall thickness is normal or slightly thickened. Heart valves are generally normal, and thrombus in the heart cavity, especially in the apex, is not uncommon. Under light microscope, extensive fibrosis can be seen in stroma and around blood vessels, especially involving left ventricular endocardium. Occasionally, small-scale necrosis and cell infiltration can be seen, and the size of myocardial cells is obviously different, some are hypertrophy and some are atrophy.
Folding disease symptoms
Patients may be asymptomatic in the early stage, with slow onset and progressive clinical symptoms, mainly manifested as left heart failure, and fatigue and fatigue caused by decreased cardiac output are more common. Shortness of breath after work or fatigue at first, then shortness of breath during light activity or rest, or paroxysmal shortness of breath at night. The symptoms of right heart failure appear late and hidden, especially suggesting a poor prognosis. Arrhythmia, thromboembolism and sudden death are common symptoms that can occur at any stage of the disease.
Folding physical examination
Physical examination often finds signs of heart enlargement and congestive heart failure in different degrees. The general arterial pressure is normal or low, and the pulse pressure decreases, reflecting the decrease of cardiac output. When the right heart fails, the jugular vein can be dilated, and peripheral edema and ascites can appear in the late stage.
Left ventricular pulsation can be found in the precordial area, and the position of apical pulsation often deviates to the outside, reflecting the enlargement of left ventricle. Auscultation can hear the galloping rhythm before cardiac contraction, which usually appears before the obvious symptoms of congestive heart failure. Once the heart is decompensated, there will always be ventricular gallop. Midsystolic murmurs are common, mostly caused by mitral regurgitation and tricuspid regurgitation.
Folding auxiliary inspection
1. ECG: the amplitude of R wave is abnormal, a few cases have pathological Q wave, ST segment decreases and T wave is inverted. Ventricular arrhythmia, atrial fibrillation, atrioventricular block and left bundle branch block are the most common arrhythmias.
2.x-ray examination: enlarged heart shadow, cardiothoracic ratio greater than 0.5, pulmonary congestion sign.
3. Echocardiography: the heart can be enlarged in the apical four chambers, especially in the left ventricle, and the motion of the left ventricular wall is diffusely weakened; If there is mural thrombus, it mostly occurs at the tip of left ventricle; Mitral and tricuspid regurgitation is common. The measurement of ejection fraction and left ventricular diameter shortening rate can reflect ventricular systolic function. Segmental abnormality of wall motion should be differentiated from ischemic myocardial disease, and echocardiography combined with dobutamine stress test is helpful for differentiation. The picture below is a three-dimensional echocardiography image of dilated cardiomyopathy.
Three-dimensional echocardiographic images of dilated cardiomyopathy
4. Coronary angiography: DCM patients with chest pain need coronary angiography or coronary CTA detection, which is helpful to differentiate from coronary heart disease. Left ventricular angiography showed that the ventricular cavity was enlarged and the overall wall motion was weakened.
5. Endocardial myocardial biopsy: hypertrophy, degeneration and interstitial fibrosis of myocardial cells are not specific for the diagnosis of dilated cardiomyopathy, but they are helpful to distinguish from specific myocardial diseases and acute myocarditis. Polymerase chain reaction or in situ hybridization of endocardial biopsy specimens is helpful for the diagnosis of infection. Or genetic analysis of specific cell abnormalities.
6. Radionuclide imaging: It can effectively distinguish heart failure caused by ischemic or non-ischemic reasons, and can measure the size of ventricular cavity, abnormal wall motion and ejection fraction. With the maturity and wide popularization of echocardiography technology, this technology has not been used routinely.
7. Serum immunological examination: Using isolated myocardial natural protein or synthetic peptide as antigen, enzyme-linked immunosorbent assay (ELISA) was used to detect anti-L-type calcium channel antibody, anti-ADP/ATP carrier antibody, anti-β 1 receptor antibody, anti-M2 cholinergic receptor antibody and anti-myosin heavy chain antibody, which is helpful for the immunological diagnosis of dilated cardiomyopathy.
8. Detection of peripheral blood virus RT-PCR, detection of enterovirus RNA, detection of Cox B-IgM, CMV-IgM and adenovirus -IgM will help to find the relationship between this disease and viral infection, and provide a new basis for the pathogenesis of this disease.
1. If the cause can be determined by medical history and auxiliary examination, the diagnosis of the cause should be indicated, such as idiopathic, familial/hereditary, virus and/or immunity, alcohol/toxic.
2. The left ventricle or both ventricles are enlarged, and the ventricular systolic function is impaired. Echocardiography showed that the left ventricular end-diastolic diameter was more than 5 cm (female) ~ 137.5px (male), the left ventricular ejection fraction was less than 40%, and the diffuse motion of the ventricular wall was weakened. The patients' cardiac function grading refers to new york's cardiac function grading.
3. According to the data of multicenter clinical trials of dilated cardiomyopathy in China, the course of dilated cardiomyopathy can be divided into three stages: ① no heart failure stage, normal physical examination, slight enlargement of the heart by X-ray examination and nonspecific changes in electrocardiogram. The left ventricular end-diastolic diameter measured by echocardiography is 5 ~ 5~ 150px, and the ejection fraction is between 40% and 50%. ② The main symptoms of heart failure stage are extreme fatigue, fatigue, shortness of breath and palpitation. The left ventricular end-diastolic diameter measured by echocardiography is 6 ~ 175px, and the ejection fraction is between 30% and 40%. ③ Late stage of heart failure, liver enlargement, edema, ascites and other manifestations of heart failure, progressive aggravation of heart failure and short-term death. Echocardiography showed that the left ventricular end-diastolic diameter was greater than 175px, and the ejection fraction was less than 30%.
Fold and edit this disease treatment
Folding principle
1. Effectively control heart failure and arrhythmia, reduce immune-mediated myocardial injury, and improve the quality of life and survival rate of patients with dilated cardiomyopathy.
2. You can have a heart transplant in the late stage.
Folding drug therapy
Conventional treatment of heart failure
⑴ Angiotensin Converting Enzyme Inhibitor (ACEI): It can improve hemodynamic changes and abnormal activation of neurohormones in heart failure, thus protecting myocardium. Commonly used drugs include captopril, perindopril and benazepril. Those who use diuretics at the same time should pay attention to low blood pressure. Can't tolerate ACEI, switch to angiotensin antagonists (ARB), such as candesartan and valsartan.
⑵ Beta blockers: It can improve the over-activation of neurohormonal mechanism in heart failure and inhibit myocardial injury mediated by anti-β 1 receptor antibody. After the improvement of water retention in patients with heart failure, β -blockers were used, which were suitable for patients with rapid heart rate, ventricular arrhythmia and positive anti-β 1- receptor antibody. Commonly used drugs are metoprolol sustained-release tablets or flat tablets, starting from 6.25mg, twice a day, doubling the dose every two weeks, and gradually increasing to 25 mg ~ 100 mg, twice a day. Carvedilol starts from 6.25mg, twice a day, and the dose is doubled every two weeks, gradually increasing to 25mg, twice a day.
⑶ Spironolactone can inhibit myocardial fibrosis and improve the prognosis of patients with heart failure. Dosage: 10mg ~ 20mg/ day, 1 time/day. Not suitable for patients with impaired renal function and elevated blood potassium.
⑷ Diuretics: oral furosemide 20 mg ~ 40 mg, daily 1 time, intermittent diuresis, potassium and magnesium supplementation and proper sodium salt diet.
5. Positive inotropic drugs: the dose of digitalis should be small, and the basic dose of digoxin should be 0.1.25mg/d. Non-digitalis positive inotropic drugs, such as dopamine and dobutamine, should be used for 3-7 days in the critical period to improve patients' symptoms and get through the critical period.
2. Astragalus membranaceus: It has antiviral and immunomodulatory effects. In view of the persistent infection of enterovirus RNA in patients with dilated cardiomyopathy, astragalus can be used to treat dilated cardiomyopathy.
3. Improve myocardial metabolism: Coenzyme Q 10 participates in oxidative phosphorylation and energy production, and has anti-oxygen free radicals and membrane stability.
4. Prevention and treatment of embolism and sudden death
(1) prevention of embolism: aspirin 75 ~ 100 mg/d, warfarin 1.5 ~ 3 mg/d are adjusted according to INR 1.8 ~ 2.5, so as to prevent the formation of adherent thrombus and embolism.
⑵ Prevention of sudden death: mainly control the reversible factors that induce ventricular arrhythmia: ① correct heart failure and reduce ventricular wall tension; ② Correcting low potassium and magnesium; ③ To improve neurohormonal dysfunction, angiotensin converting enzyme inhibitor and metoprolol were selected; ④ Avoid the toxic and side effects of digitalis, diuretics and other pharmaceutical factors; ⑤ Amiodarone can effectively control arrhythmia and prevent sudden death.
Folding resynchronization therapy
Cardiac resynchronization therapy is to make the left ventricular free wall and interventricular septum contract synchronously again, improve the left ventricular contraction efficiency and improve cardiac function. In ACC/AHA pacing guidelines, symptomatic heart failure caused by primary dilated cardiomyopathy or ischemic cardiomyopathy, QRS interval of electrocardiogram ≥ 130ms, cardiac function ≥ Nyha Ⅲ/Ⅳ, left ventricular end-diastolic diameter ≥55mm, EF≤35% are listed as Class Ⅱ A indications for biventricular pacing. The indications of CRT in the US Food and Drug Administration are: NYHA Ⅲ ~ Ⅳ Ⅲ ~ Ⅳ, left ventricular EF≤35%, QRS interval ≥ 130ms, optimized drug therapy and normal sinus rhythm.
The Department of Cardiology of the General Hospital of Chinese People's Liberation Army is at the leading level in China in resynchronization therapy. The ultrasound room of cardiology department can provide the detection of preoperative screening index SDI for resynchronization therapy and provide data support for postoperative monitoring of patients.
Folding surgical treatment
For DCM patients with severe atrioventricular regurgitation, surgical intervention can be used to repair the mitral valve with normal structure but insufficient function. Patients with dilated cardiomyopathy can use left ventricular assist devices in the late stage. If the indications are clear, you can also consider heart transplantation.