Eisenmenger syndrome (ES) is usually a pathophysiological syndrome in which elevated pulmonary vascular resistance in various left-to-right shunted congenital heart diseases brings pulmonary artery pressure to or above that of the body circulation, resulting in bidirectional or reverse shunting of blood through abnormal intracardiac or extracardiac pathways. In 1987, Dr. Eisenmenger, an Austrian physician, first described clinically and pathologically a case of a 32-year-old male patient with clinical signs including cyanosis, markedly decreased exercise tolerance, and heart failure, who finally died of recurrent hemoptysis. After an autopsy confirmed the presence of a large ventricular septal defect and aortic span, Bing et al. in 1947 added the concept of pulmonary artery pressure reaching body circulation pressure to the anatomical definition and defined Eisenmenger complex as a large ventricular septal defect with In 1958, Wood et al. reported that elevated pulmonary artery pressure and pulmonary vascular resistance could also occur in other congenital defects of the heart or great vessels, causing similar clinical symptoms, and renamed this syndrome “Eisenmenger syndrome “, defined as any congenital heart disease in which body circulation traffic is present, due to an increase in pulmonary vascular resistance (>800 dynes.s/cm5) that brings pulmonary artery pressure to the level of body circulation pressure, resulting in a bidirectional or reverse shunt at the intracardiac or great vessel level. Eisenmenger syndrome is a late complication of unoperated left-to-right shunt congenital heart disease, and the development of severe pulmonary hypertension is rare in developed countries due to early surgical treatment of these patients, while in China, due to the vast geographical area and unbalanced economic development, although the diagnosis and treatment of congenital heart disease have made great progress in recent years, there are still a large number of patients with severe pulmonary hypertension Although the diagnosis and treatment of congenital heart disease have made great progress in recent years, there are still a large number of patients with severe pulmonary hypertension that are not treated in time and eventually develop into Eisenmenger syndrome, thus losing the opportunity of surgery. The natural course of Eisenmenger’s syndrome varies widely among individuals, but the overall survival rate is significantly better than that of patients with idiopathic pulmonary hypertension. Patients with idiopathic pulmonary hypertension have a mean survival time of only 2.8 years after diagnosis, whereas most patients with unoperated Eisenmenger syndrome survive into their 20s and 40s, and cases have even been reported in their 60s. However, for patients with concomitant chromosomal abnormalities (e.g., trisomy 21), the survival time is often shorter than that of patients without chromosomal abnormalities. In a multicenter study of the natural history of congenital heart disease conducted in the United States, 54% of 98 patients with unoperated ventricular septal defects combined with Eisenmenger’s syndrome survived longer than 20 years after the diagnosis of Eisenmenger. The survival time of patients with Eisenmenger syndrome is related to their age at diagnosis, and the younger the age, the longer the survival time; Clarkson et al. showed that patients aged 10 to 19 years at diagnosis had a 5-year survival rate of 95%, whereas those aged 20 years or older at diagnosis had a 5-year survival rate of only 56% (Figure 14-2-4). Figure KaplanCMeier survival curves in patients with Eisenmenger syndrome (as cited in Daliento L, Somerville J, Presbitero P, et al. Eisenmenger syndrome: factors relating to deterioration and death. Eur Heart J, 1998, 19:1845C1855.) Patients with Eisenmenger syndrome have a better prognosis than other types of pulmonary hypertension for a number of possible reasons. Although there is no significant difference in the degree of pulmonary artery pressure between the two, the progression of pulmonary vasculopathy due to high blood flow may be slower, thus allowing more time for the right ventricle to adjust to changes in pulmonary vascular resistance, whereas in patients with idiopathic pulmonary hypertension and other types of pulmonary hypertension, the pulmonary vasculopathy develops more rapidly, with rapid onset of progressive right ventricular enlargement and cardiac failure, which This leads to congestive heart failure. On the other hand, in Eisenmenger syndrome, which results from prolonged high blood flow and pressure in the pulmonary circulation, the right ventricle maintains a high degree of myocardialization after infancy without significant wall degeneration and thinning due to the presence of large shunts in the body-pulmonary circulation after birth, and thus may have an increased ability to tolerate elevated pulmonary artery pressure and increased pulmonary vascular resistance. In addition, the presence of a body-pulmonary shunt may have a protective effect in patients with Eisenmenger syndrome. In patients with idiopathic pulmonary hypertension, patients with intact foramen ovale survive longer than those with an intact septum, and the use of a balloon atrial septal stoma improves the prognosis of patients with idiopathic pulmonary hypertension to some extent, possibly because the presence of a body-pulmonary shunt relieves right ventricular pressure This may be due to the fact that the presence of a body-pulmonary circulation shunt relieves elevated right ventricular pressure, thereby maintaining effective left cardiac output and providing adequate tissue perfusion and oxygen supply. The presence of a body-pulmonary shunt is particularly important during activity to relieve right ventricular pressure during a rapid rise in pulmonary artery pressure. In Eisenmenger syndrome, an objective and comprehensive understanding of the natural history and hemodynamic features is required. Inappropriate treatment of the primary disease, such as closure of patent ductus arteriosus or ventricular septal defect, as a means to treat the syndrome is counterproductive and can contribute to early premature death of the patient once treatment of the primary disease is obtained.