Decreased work tolerance is a typical symptom of chronic pulmonary heart disease, which is a heart disease caused by chronic lesions of the lungs, thorax or pulmonary arteries that increase the resistance of the pulmonary circulation, resulting in pulmonary hypertension and right ventricular hypertrophy, and finally right heart failure, referred to as pulmonary heart disease. Its clinical features include cough, sputum, palpitations after activity, dyspnea, swelling of the lower limbs, emphysema and dilated pulmonary artery branches on X-ray, and enlarged right atrium or right ventricle on echocardiography. The course of the disease develops slowly. Firstly, patients mostly have a history of long-term chronic cough, cough or asthma, and gradually develop weakness and dyspnea, and secondly, palpitations, shortness of breath and cyanosis gradually appear, especially in the event of acute respiratory tract infection, the ventilation disorder is further aggravated, which causes hypoxia and carbon dioxide retention and leads to respiratory failure and heart failure. Chronic pulmonary heart disease should pay attention to the differential diagnosis with the following diseases: 1, and coronary heart disease Differentiation Coronary heart disease and pulmonary heart disease are mostly seen in middle-aged people, both can appear heart enlargement, arrhythmia and heart failure, both heart murmur is not obvious, pulmonary heart disease electrocardiogram has similar myocardial infarction graphics, resulting in diagnostic difficulties. Differentiation points: ① Patients with pulmonary heart disease mostly have a history and signs of chronic bronchitis and emphysema without typical angina pectoris or myocardial infarction manifestations; ② electrocardiogram ST-T wave changes in pulmonary heart disease are mostly inconspicuous, similar to myocardial infarction graphics mostly occur in the acute exacerbation of pulmonary heart disease, with the improvement of these graphics can disappear, pulmonary heart disease can also appear a variety of arrhythmias, mostly more normal after the removal of the trigger, that is, transient and Pulmonary heart disease can also present with a variety of arrhythmias that are more normal when the trigger is removed, i.e. transient and variable. Coronary artery disease often has atrial fibrillation and various conduction blocks, which are constant and persistent compared to pulmonary artery disease. The diagnosis of pulmonary heart disease with coronary artery disease is difficult and often missed, with a misdiagnosis rate of 8% to 38% and 12% to 26% in foreign countries. The following points support the diagnosis of pulmonary heart disease with coronary artery disease: (1) The presence of long-term hypoxia and emphysema: typical angina symptoms are few, such as discomfort in the precordial region, chest tightness aggravated by taking nitroglycerin for 3 to 5 min to relieve. (2) The second sound of the aortic valve is greater than the second sound of the pulmonary valve: an apical grade 2/6 or more variable systolic murmur, suggesting papillary muscle malfunction. (3) X-ray shows enlargement of both right and left ventricles: aortic arch tortuosity, prolongation, calcification, heart enlargement, aortic type, aortic-micuspid type and large left ventricular predominantly large size. (4) Electrocardiographic changes: myocardial infarction pattern to exclude cool myocardial infarction, complete left bundle branch block, left anterior hemiblock and/or double bundle branch block, left ventricular hypertrophy or strain to exclude hypertension, second to third degree atrioventricular block, and severe left deviation of the electrical axis (<-300°) to exclude hypertension. (5) The echocardiogram shows a decrease in the amplitude of left ventricular posterior wall motion: the difference in the end-diastolic internal diameter of the left ventricle is <10 mm. 2. Differentiation from wind heart disease Mitral stenosis in wind heart disease can cause pulmonary hypertension, right heart involvement, and myocardial contraction weakness in heart failure is not easy to hear the typical murmur, which is easily confused with pulmonary heart disease. In pulmonary heart disease, the tricuspid valve is relatively incompetent and the heart is transposed in the cis-clockwise direction, and a 2/6 to 3/6 grade blowing murmur can be heard in the original mitral valve area. Differentiation points: (1) Pulmonary heart disease mostly develops in middle age or older, while wind heart disease is more common in adolescents. (2) Pulmonary heart disease has a history of respiratory disease for many years, with reduced respiratory function and often heart failure based on respiratory failure; rheumatic heart disease often has a history of rheumatism, and rheumatic activity and exertion are often triggers of heart failure. (3) The murmur of pulmonary heart disease is enhanced after heart failure, while rheumatic heart disease can be attenuated. (4) Pulmonary heart disease often shows right heart failure, while wind heart disease often shows left heart failure. (5) X-ray changes: pulmonary heart disease is dominated by large right ventricle, while wind heart disease is dominated by large left atrium showing mitral heart changes. (6) Blood gas analysis: PaO2 is often decreased or PaCO2 is increased in pulmonary heart disease, but may be normal in wind heart disease. (7) Electrocardiogram: pulmonary heart disease has pulmonary P waves and right ventricular hypertrophy, while wind heart disease has mitral P waves. 3. Differentiation from constrictive pericarditis Constrictive pericarditis has insidious onset, clinical manifestations include palpitations, shortness of breath, cyanosis, jugular venous anger, hepatomegaly, ascites, ECG low voltage similar to pulmonary heart disease, but no history of chronic bronchitis, pulse pressure becomes smaller, X-ray heart waist becomes straight, heart beat is weak or disappears, pericardial calcification is visible, but no emphysema and pulmonary hypertension, which can be differentiated from pulmonary heart disease. 4. Differentiate from primary cardiomyopathy Primary cardiomyopathy is similar to pulmonary heart disease in terms of enlarged heart, weak heart sounds, murmurs due to atrioventricular valve relative closure insufficiency and hepatomegaly, ascites and lower limb edema due to right heart failure. Pulmonary cardiopathy has a history of chronic respiratory infection and signs of emphysema, pulmonary hypertension on X-ray, and electrocardiogram with right-sided electrical axis and cis-clockwise transposition, whereas cardiomyopathy is characterized by extensive myocardial damage, echocardiogram shows "large ventricle, small opening", blood gas changes are not obvious, and there may be mild hypoxemia.