bubble_chart Overview

The characteristic feature of this type is primary myocardial and/or endocardial fibrosis, or infiltrative myocardial lesions, leading to diastolic dysfunction caused by impaired cardiac filling.

bubble_chart Etiology

The exact cause remains unclear. Apart from sexually transmitted diseases, research on the mechanism of non-infiltrative cardiomyopathy has focused on eosinophils. Many patients with this type of cardiomyopathy in tropical and temperate regions are associated with eosinophilia. The early stage is the necrotic phase, characterized by numerous eosinophils in the myocardium, typically within 5 weeks. By 10 months, the endocardial membrane thickens with thrombus formation, and myocardial inflammation decreases, marking the thrombotic phase. After 2 years, the fibrotic phase begins, with fibrosis occurring in both the endocardial membrane and myocardium.

bubble_chart Pathological Changes

In infiltrative sexually transmitted disease-induced restrictive cardiomyopathy, there are types such as amyloidosis (accumulation of amyloid material in the interstitium), fleshy tumor-like infiltration (fleshy tumor-like material infiltration within the myocardium), hemochromatosis (deposition of hemosiderin in the myocardium), and glycogen storage disease (excessive accumulation of glycogen in the myocardium). Among non-infiltrative restrictive cardiomyopathies, there are two types: endomyocardial fibrosis and Löffler endocarditis. The former is found in tropical regions, while the latter occurs in temperate zones, though they are practically similar. The heart exhibits grade I or grade II enlargement macroscopically, with significant fibrosis and thickening of the endocardium, primarily affecting the ventricular inflow tract and apex. The atrioventricular valves may also be involved, and fibrosis can extend deep into the myocardium. Mural thrombi are prone to form, and the ventricular cavities shrink. Calcification may also occur in the endomyocardium.

Pathophysiology: Endocardial and myocardial fibrosis impair ventricular relaxation and may also be accompanied by varying degrees of systolic dysfunction. The reduction in ventricular cavity size restricts ventricular filling, while decreased ventricular compliance hinders venous return, subsequently reducing cardiac output. These changes result in pathophysiological alterations similar to those seen in constrictive pericarditis. When the atrioventricular valves are affected, mitral or tricuspid regurgitation may occur.

bubble_chart Clinical Manifestations

The onset is relatively slow. Early symptoms may include fever, gradually progressing to lack of strength, dizziness, and shortness of breath. In cases where the left ventricle is predominantly affected, manifestations of left heart failure and pulmonary stirred pulse hypertension may occur, such as shortness of breath, cough, hemoptysis, rales at the lung bases, and accentuated second heart sound in the pulmonary stirred pulse valve area. In cases where the right ventricle is predominantly affected, signs of impaired left ventricular venous return may appear, such as distended neck veins, hepatomegaly, lower limb edema, and ascites. Cardiac pulsations are often weakened, the dullness border is grade I enlarged, heart sounds are faint, the heart rate is rapid, and there may be a diastolic gallop rhythm and arrhythmias. Pericardial effusion may also be present. Visceral embolism is not uncommon.

X-ray examination reveals an enlarged cardiac shadow, and calcification shadows of the endocardial membrane and myocardium may be observed. Ventriculography shows a reduction in ventricular cavity size. Electrocardiogram findings include low voltage, atrial or ventricular hypertrophy, bundle branch block, ST-T changes, atrial fibrillation, and abnormal Q waves may also be seen in leads V₁

and V₂. Echocardiography may reveal thickening of the endocardial membrane, obliteration of the ventricular cavity at the apex, abnormal echo density of the myocardial-endocardial membrane structure, and weakened ventricular wall motion. In primary cases, the ventricular wall does not thicken, whereas in infiltrative sexually transmitted disease cases, the ventricular wall may thicken, with rapid early diastolic filling but extremely slow mid-to-late stage [third stage] filling. The pericardial membrane generally does not thicken. Cardiac catheterization shows a gradual rise in ventricular end-diastolic pressure, resulting in a dip-and-plateau waveform. In cases with predominant left ventricular involvement, pulmonary stirred pulse pressure may be elevated, while in cases with predominant right ventricular involvement, right atrial pressure is high, and the right atrial pressure curve shows a prominent v wave replacing the a wave. Systolic time interval measurements are abnormal.

bubble_chart Diagnosis

Since the clinical manifestations of this type are not obvious in the early stages, diagnosis is challenging. Once clinical symptoms appear, various examinations can confirm the diagnosis, with echocardiography being a non-invasive and effective method. Myocardial and endocardial biopsy, if yielding positive specific findings, aids in diagnosis and may also reveal infiltrative sexually transmitted disease changes. Clinically, it must be differentiated from constrictive pericarditis, especially restrictive cardiomyopathy predominantly affecting the right ventricle, as both share similar clinical presentations. A history of acute pericarditis, pericardial calcification on X-ray, or pericardial thickening on chest CT or MRI supports pericarditis. Conversely, atrial or ventricular hypertrophy, bundle branch block on electrocardiogram, or abnormal systolic time intervals suggest cardiomyopathy. Echocardiography significantly aids in distinguishing between the two, with apical cavity obliteration and endocardial thickening confirming cardiomyopathy. For challenging cases, ventricular angiography and endocardial myocardial biopsy may be performed.

bubble_chart Treatment Measures

Prevention is limited to avoiding complications. Avoid fatigue and prevent infections. Treatment is primarily symptomatic. Patients with atrial fibrillation may be given Rehmannia; those with edema and ascites should use diuretics. When using diuretics or vasodilators, care should be taken to avoid excessive reduction in ventricular filling pressure, which may impair cardiac function. Anticoagulants may be used to prevent embolism. In recent years, surgical removal of fibrotic and thickened endocardium, along with artificial valve replacement for damaged atrioventricular valves, has shown favorable results.

bubble_chart Prognosis

The progression of the disease varies in speed. In the past, due to incomplete treatment, once symptoms appeared, patients gradually lost their ability to work and ultimately faced death. The prognosis for those with left ventricular lesions is slightly worse than for those with right ventricular lesions. In recent years, surgical treatment has offered some hope.