重庆医科大学：《内科学》课程教学课件（PPT讲稿）Cardiomyopathies

Cardiomyopathies

Cardiomyopathies

Introduction Cardiomyopathies are a group of diseases affecting the myocardium primarily Less information is available about cardiac muscle disorders than about other forms of cardiac disease such as valvular,congenital,or coronary heart disease.Some forms of cardiomyopathy have a clear-cut cause,while many other types of myocardial disease occur without explanation.Because of the scarcity of knowledge concerning heart muscle disorders,a number of different classification schemes have been suggested,based on the pathologic and hemodynamic abnormality present.We favor the classification summarized in Table 1

Introduction ◼ Cardiomyopathies are a group of diseases affecting the myocardium primarily .Less information is available about cardiac muscle disorders than about other forms of cardiac disease such as valvular, congenital,or coronary heart disease. Some forms of cardiomyopathy have a clear-cut cause, while many other types of myocardial disease occur without explanation. Because of the scarcity of knowledge concerning heart muscle disorders, a number of different classification schemes have been suggested, based on the pathologic and hemodynamic abnormality present. We favor the classification summarized in Table 1

Table 1 Dilated(congestive)cardiomyopathy(85%)-with dilated left ventricle and impaired systole Hypertrophic(Obstructive)cardiomyopathy(10% )hypertrophy of ventricles,especially the interventricular septum. Restrictive cardiomyopathy(5%)-restricted ventricular filling

Table 1 ◼ Dilated(congestive)cardiomyopathy(85%)-with dilated left ventricle and impaired systole ◼ Hypertrophic(Obstructive)cardiomyopathy( 10% )hypertrophy of ventricles, especially the interventricular septum. ◼ Restrictive cardiomyopathy(5%)-restricted ventricular filling

正常 打扩张型心肌病 肥厚型心肌病 限制型心肌闲

Dilated Cardiomyopathy Introduction Dilated cardiomyopathy (DCM)is a syndrome characterized by cardiac enlargement and impaired systolic function of one or both ventricles. Although it was formerly called congestive cardiomyopathy,the term dilated cardiomyopathy is now preferred because the earliest abnormality usually is ventricular enlargement and systolic contractile dysfunction,with congestive heart failure often developing later. ■Epidemiology The incidence of DCM is reported to about 5 to 8 cases per 100,000 population per year and appear to be increasing,although the true figure likely is higher as a consequence of underreporting of mild or asymptomatic cases.It occurs almost three times more frequently in blacks and males than in white and females,and this difference does not appear to be related solely to differing degrees of hypertension, cigarette smoking,or alcohol use;furthermore,survival in blacks appears to be worse than in whites

Dilated Cardiomyopathy ◼ Introduction ◼ Dilated cardiomyopathy (DCM) is a syndrome characterized by cardiac enlargement and impaired systolic function of one or both ventricles. Although it was formerly called congestive cardiomyopathy, the term dilated cardiomyopathy is now preferred because the earliest abnormality usually is ventricular enlargement and systolic contractile dysfunction, with congestive heart failure often developing later. ◼ Epidemiology The incidence of DCM is reported to about 5 to 8 cases per 100,000 population per year and appear to be increasing, although the true figure likely is higher as a consequence of underreporting of mild or asymptomatic cases. It occurs almost three times more frequently in blacks and males than in white and females, and this difference does not appear to be related solely to differing degrees of hypertension, cigarette smoking, or alcohol use; furthermore, survival in blacks appears to be worse than in whites

Etiology In some forms of cardiomyopathy the etiology of the disease is known.These types of cardiomyopathy are said to be secondary,as contrasted with primary forms of heart disease, in which the cause is known.It is likely that DCM represents a common expression of myocardial damage that has been produced by a variety of as yet unestablished myocardial insults. Although the causes remain unclear,interest has centered on three possible basic mechanisms of damage:familial and genetic factors;viral myocarditis and other cytotoxic insults;and immunological abnormality

Etiology ◼ In some forms of cardiomyopathy the etiology of the disease is known. These types of cardiomyopathy are said to be secondary, as contrasted with primary forms of heart disease, in which the cause is known. It is likely that DCM represents a common expression of myocardial damage that has been produced by a variety of as yet unestablished myocardial insults. Although the causes remain unclear, interest has centered on three possible basic mechanisms of damage: familial and genetic factors; viral myocarditis and other cytotoxic insults; and immunological abnormality

Pathology Postmortem Examination.This reveals enlargement and dilatation of all four chambers;the ventricles are more dilated than the atria.Although the thickness of ventricular wall is increased in some cases,the degree of hypertrophy often is less than might be expected given the severe dilation present.The cardiac valves are intrinsically normal, and intracavitary thrombi, particularly in the ventricular apex,are common.The coronary arteries usually are normal.The right ventricle is preferentially involved in some cases of dilated cardiomyopathy,sometimes on a familial basis

Pathology ◼ Postmortem Examination. This reveals enlargement and dilatation of all four chambers; the ventricles are more dilated than the atria. Although the thickness of ventricular wall is increased in some cases, the degree of hypertrophy often is less than might be expected given the severe dilation present. The cardiac valves are intrinsically normal, and intracavitary thrombi, particularly in the ventricular apex, are common. The coronary arteries usually are normal. The right ventricle is preferentially involved in some cases of dilated cardiomyopathy, sometimes on a familial basis

Histological Examination.Microscopic study reveals extensive areas of interstitial and perivascular fibrosis, particularly involving the left ventricular subendocardium. Small areas of necrosis and cellular infiltrate are seen on occasion,but these typically are not prominent features. There is marked variation in myocyte size;some myocardial cells are hypertrophied and others are atrophied.Cardiac biopsy specimens obtained during life demonstrate a variety of similar abnormalities,including interstitial fibrosis,cellular infiltrates,myocyte hypertrophy,and myocardial cell degeneration.No viruses or other etiological agents have been identified with any regularity in tissue from patients with DCM.Particularly disappointing has been the failure to identify any immunological, histochemical, morphological, ultrastructural,or microbiological marker that might be used to establish the diagnosis of idiopathic dilated cardiomyopathy or to clarify its cause

◼ Histological Examination. Microscopic study reveals extensive areas of interstitial and perivascular fibrosis, particularly involving the left ventricular subendocardium. Small areas of necrosis and cellular infiltrate are seen on occasion, but these typically are not prominent features. There is marked variation in myocyte size; some myocardial cells are hypertrophied and others are atrophied. Cardiac biopsy specimens obtained during life demonstrate a variety of similar abnormalities, including interstitial fibrosis, cellular infiltrates, myocyte hypertrophy, and myocardial cell degeneration. No viruses or other etiological agents have been identified with any regularity in tissue from patients with DCM. Particularly disappointing has been the failure to identify any immunological, histochemical, morphological, ultrastructural, or microbiological marker that might be used to establish the diagnosis of idiopathic dilated cardiomyopathy or to clarify its cause

Clinical Manifestations History.Symptoms usually develop gradually in patients with DCM. Some patients are asymptomatic and yet have left ventricular dilation for months or even years which is clinically recognized only later when symptoms develop or when routine chest roentgenography demonstrate cardiomegaly.Other patients,after recovery from what appears to be a systemic viral infection,develop symptoms of heart failure for the first time.In still others,severe heart failure develops acutely during an episode of myocarditis although some recovery occurs,chronic manifestations of diminished cardiac reserve persist and heart failure reappears months or years later.It is important to carefully question the patient and family about alcohol consumption,because excessive alcohol consumption is a major cause of secondary DCM,and its cessation may result in substantial clinical improvement.Although patients of any age may be affected,the disease is most common in middle age and is more frequent in men than in woman

Clinical Manifestations ◼ History. Symptoms usually develop gradually in patients with DCM. Some patients are asymptomatic and yet have left ventricular dilation for months or even years which is clinically recognized only later when symptoms develop or when routine chest roentgenography demonstrate cardiomegaly. Other patients, after recovery from what appears to be a systemic viral infection, develop symptoms of heart failure for the first time. In still others, severe heart failure develops acutely during an episode of myocarditis ; although some recovery occurs, chronic manifestations of diminished cardiac reserve persist and heart failure reappears months or years later. It is important to carefully question the patient and family about alcohol consumption, because excessive alcohol consumption is a major cause of secondary DCM, and its cessation may result in substantial clinical improvement. Although patients of any age may be affected, the disease is most common in middle age and is more frequent in men than in woman

The most striking symptoms are those of left ventricular failure.Fatigue and weakness due to diminished cardiac output are common.Exercise intolerance is common and relates,at least in part,to reduced skeletal muscle perfusion as well as histological and biochemical alterations in the exercising muscle groups.Right heart failure is a late and ominous sign and is associated with a particularly poor prognosis.Chest pain occurs in about one-third of patients and may suggest concomitant ischemic heart disease.A reduction in the vasodilator reserve of coronary microvasculature in DCM suggests that subendocardial ischemia may play a role in the genesis of chest pain despite angiographically normal coronary arteries.Chest pain secondary to congestive hepatomegaly are frequent in the late stages of illness

◼ The most striking symptoms are those of left ventricular failure. Fatigue and weakness due to diminished cardiac output are common. Exercise intolerance is common and relates, at least in part, to reduced skeletal muscle perfusion as well as histological and biochemical alterations in the exercising muscle groups. Right heart failure is a late and ominous sign and is associated with a particularly poor prognosis. Chest pain occurs in about one-third of patients and may suggest concomitant ischemic heart disease. A reduction in the vasodilator reserve of coronary microvasculature in DCM suggests that subendocardial ischemia may play a role in the genesis of chest pain despite angiographically normal coronary arteries. Chest pain secondary to congestive hepatomegaly are frequent in the late stages of illness