Chronic pulmonary heart disease is a cardiac condition caused by chronic pathological changes in the lung tissue, pulmonary blood vessels, or thoracic cage, leading to structural and functional abnormalities in the lung tissue. This results in increased pulmonary vascular resistance and elevated pulmonary artery pressure, causing right ventricular dilation and hypertrophy, with or without accompanying right heart failure.

bubble_chart Etiology

According to the different sites of the primary disease, it can be divided into three categories:

1. Bronchial and pulmonary diseases: Chronic obstructive pulmonary disease (COPD) caused by chronic bronchitis complicated by obstructive lung qi swelling is the most common, accounting for about 80-90%. This is followed by bronchial asthma, bronchiectasis, severe pulmonary subcutaneous nodules, pneumoconiosis, chronic diffuse pulmonary interstitial fibrosis, sarcoidosis, allergic alveolitis, eosinophilic granuloma, etc.
2. Thoracic movement disorders: These are relatively rare. Severe spinal kyphosis, scoliosis, spinal subcutaneous nodules, wind-dampness arthritis, extensive pleural adhesions, and severe thoracic or spinal deformities caused by thoracoplasty, as well as neuromuscular diseases such as poliomyelitis, can restrict thoracic movement, compress the lungs, or twist or deform the bronchi. This leads to restricted lung function, poor airway drainage, recurrent lung infections, complications such as lung qi swelling or fibrosis, hypoxia, pulmonary vasoconstriction, and stenosis, increasing resistance, pulmonary stirred pulse hypertension, and ultimately developing into lung heart disease.
3. Pulmonary vascular diseases: These are very rare. Allergic granulomatosis involving the pulmonary stirred pulse, widespread or recurrent multiple small pulmonary stirred pulse embolisms and small pulmonary stirred pulse inflammation, as well as idiopathic primary pulmonary stirred pulse hypertension, can all cause stenosis or blockage of the small pulmonary stirred pulse. This increases pulmonary stirred pulse vascular resistance, leads to pulmonary stirred pulse hypertension and right ventricular overload, and progresses to lung heart disease.
4. Others: Primary alveolar hypoventilation, congenital oropharyngeal deformities, sleep apnea syndrome, etc., can also lead to pulmonary heart disease. These conditions can all cause hypoxemia, increase pulmonary vascular contractile reactivity, result in pulmonary stirred pulse hypertension, and develop into lung heart disease.

bubble_chart Pathogenesis

There are many factors that cause right ventricular hypertrophy, some of which are not yet well understood. However, the prerequisite is irreversible changes in the function and structure of the lungs, leading to recurrent airway infections and hypoxemia. This results in a series of changes in humoral factors and pulmonary blood vessels, increasing pulmonary vascular resistance and causing structural remodeling of the pulmonary blood vessels, leading to pulmonary hypertension.

1. The formation of pulmonary hypertension

   (1) Functional factors increasing pulmonary vascular resistance Hypoxia, hypercapnia, and respiratory acidosis cause pulmonary vasoconstriction and spasm. There are many reasons for hypoxic pulmonary vasoconstriction, often observed from neural and humoral factors. Currently, humoral factors are considered to play a significant role in hypoxic pulmonary vasoconstriction. Particularly noteworthy are the cyclooxygenase products of arachidonic acid, such as prostaglandins, and the lipoxygenase products, leukotrienes (LTs). Leukotrienes primarily have vasoconstrictive effects. During hypoxia, the levels of vasoconstrictive active substances increase, causing pulmonary vasoconstriction and increased vascular resistance, leading to pulmonary hypertension. Additionally, histamine, 5-hydroxytryptamine (5-HT), angiotensin II, and platelet-activating factor (PAF) are involved in hypoxic pulmonary vasoconstriction. An imbalance between endothelium-derived relaxing factors (EDRF), such as nitric oxide, and endothelium-derived contracting factors (EDCF), such as endothelin, also plays a role in hypoxic pulmonary vasoconstriction. Hypoxic pulmonary vasoconstriction does not entirely depend on the absolute amount of a certain vasoconstrictive substance but largely on the ratio between local vasoconstrictive and vasodilatory substances.

   Hypoxia can directly cause pulmonary vascular smooth muscle contraction. The mechanism may involve hypoxia increasing the permeability of smooth muscle cell membranes to Ca²⁺, raising intracellular Ca²⁺ levels, enhancing the excitation-contraction coupling effect, and leading to pulmonary vasoconstriction.

   During hypercapnia, the increase in PaCO2 itself does not constrict blood vessels. Instead, the rise in PaCO2 produces excessive H⁺, which increases vascular sensitivity to hypoxic vasoconstriction, elevating pulmonary artery pressure.

   (2) Anatomical factors increasing pulmonary vascular resistance Anatomical factors refer to the remodeling of pulmonary vascular structures, creating hemodynamic obstacles in the pulmonary circulation. The main causes include:

   1. Long-term recurrent chronic bronchitis and peribronchitis can affect adjacent small pulmonary arteries, causing vasculitis, thickening of the vessel walls, narrowing or fibrosis of the lumen, or even complete occlusion, increasing pulmonary vascular resistance and leading to pulmonary hypertension.
   2. As emphysema worsens, increased alveolar pressure compresses alveolar capillaries, also causing narrowing
      or occlusion of the capillary lumen.
   3. The rupture of alveolar walls damages the capillary network. When the loss of alveolar capillaries exceeds 70%, pulmonary circulation resistance increases, promoting the development of pulmonary hypertension.
   4. Pulmonary vasoconstriction and vascular remodeling Chronic hypoxia causes pulmonary vasoconstriction, and increased wall tension directly stimulates wall proliferation. Meanwhile, hypoxia induces the production of various growth factors (e.g., peptide growth factors) in the lungs. The smooth muscle cells of small pulmonary arteries and muscular microarteries hypertrophy or atrophy, the intercellular matrix increases, the internal elastic fibers and collagen fibers proliferate, and non-muscular microarteries become muscularized, thickening and hardening the vessel walls, narrowing the lumen, and increasing blood flow resistance. Hypoxia can also cause pericytes of non-muscular arteries to transform into smooth muscle cells, narrowing the arterial lumen.
   Additionally, pulmonary vascular diseases, such as primary pulmonary hypertension, recurrent pulmonary embolism, pulmonary interstitial fibrosis, and pneumoconiosis, can all cause pathological changes in pulmonary blood vessels, narrowing or occluding the vascular lumen, increasing pulmonary vascular resistance, and progressing to pulmonary hypertension.

   Pulmonary heart disease. Increased pulmonary vascular resistance. In pulmonary arterial hypertension, functional factors are more significant than anatomical factors. During acute exacerbations, after treatment corrects hypoxia and hypercapnia, pulmonary arterial pressure can significantly decrease, with some patients even returning to normal levels. Therefore, comprehensive treatment during the remission stage of pulmonary heart disease is also crucial.

   (3) Increased blood volume and blood viscosity Chronic hypoxia leads to secondary polycythemia and increased blood viscosity. When the hematocrit exceeds 0.55–0.60, blood viscosity significantly increases, leading to elevated blood flow resistance. Hypoxia can increase aldosterone, causing sodium and water retention. Hypoxia also constricts renal arterioles, reducing renal blood flow and further exacerbating sodium and water retention, thereby increasing blood volume. The increased blood viscosity and blood volume further elevate pulmonary artery pressure.

   Clinical studies have shown that pulmonary hypertension in obstructive pulmonary emphysema and cor pulmonale can manifest as elevated pulmonary artery pressure during both acute exacerbations and remission phases, exceeding the normal range. It may also present as intermittent pulmonary hypertension. These two phenomena may represent different stages or clinical manifestations of cor pulmonale progression, or they may be two distinct types. Clinically, pulmonary hypertension is diagnosed when the mean pulmonary artery pressure at rest is ≥20 mmHg, termed overt pulmonary hypertension. If the mean pulmonary artery pressure at rest is <20 mmHg but exceeds 30 mmHg during exercise, it is termed latent pulmonary hypertension. Patients with cor pulmonale often develop right ventricular dilation and right heart failure. <20mmHg，而運動後肺動脈平均壓>Cor pulmonale mostly occurs in middle-aged and older patients. Autopsy findings often reveal right ventricular changes, with a minority also showing left ventricular hypertrophy. In cor pulmonale, factors such as hypoxia, hypercapnia, acidosis, and relative increases in blood flow can lead to persistent worsening, resulting in biventricular hypertrophy and even left heart failure. Additionally, the following factors may contribute: (1) myocardial hypoxia, lactate accumulation, and reduced synthesis of high-energy phosphate bonds, impairing myocardial function; (2) repeated pulmonary infections and the toxic effects of bacterial toxins on the myocardium; (3) arrhythmias caused by acid-base imbalances and electrolyte disturbances. These factors can collectively affect the myocardium and hasten heart failure.

   Damage to other vital organs Hypoxia and hypercapnia not only affect the heart but also cause pathological changes in other critical organs such as the brain, liver, kidneys, gastrointestinal tract, endocrine system, and hematopoietic system, leading to multi-organ dysfunction.

2. bubble_chart Clinical Manifestations

   The disease progresses slowly. Clinically, apart from the various symptoms and signs of the original pulmonary and thoracic diseases, it mainly manifests as the gradual appearance of pulmonary and cardiac failure as well as signs of damage to other organs. It is described according to the compensatory and decompensatory stages of its function.

   1. Compensatory stage of pulmonary and cardiac function (including the stage of remission): This stage primarily presents with manifestations of chronic obstructive pulmonary disease (COPD), such as chronic cough, sputum production, and shortness of breath. Activities may induce palpitations, dyspnea, fatigue, and reduced exercise tolerance. Physical examination may reveal significant pulmonary emphysema, with auscultation often showing weakened breath sounds and occasional dry or moist rales. Mild lower limb edema may be present, more pronounced in the afternoon and disappearing the next morning. The dullness of the heart borders is often difficult to percuss due to pulmonary emphysema. Heart sounds are distant, but there may be accentuated second heart sounds in the pulmonary valve area, suggesting pulmonary hypertension. The appearance of systolic murmurs in the tricuspid valve area or subxiphoid cardiac pulsations often indicates right ventricular hypertrophy. In some cases, elevated intrathoracic pressure due to pulmonary emphysema obstructs venous return, leading to jugular vein distension. Additionally, due to diaphragmatic descent, the upper and lower borders of the liver may shift significantly downward, which should be differentiated from signs of hepatic congestion due to right heart failure. Patients with pulmonary heart disease often exhibit signs of malnutrition.
   2. Decompensatory stage of pulmonary and cardiac function (including the acute exacerbation phase): The clinical manifestations of this stage are primarily respiratory failure, with or without heart failure.
      1. Respiratory failure: Acute respiratory infections are common triggers.
      2. Heart failure: Primarily manifests as right heart failure, but arrhythmias may also occur.

   bubble_chart Auxiliary Examination

   1. X-ray examination In addition to the characteristics of underlying pulmonary and thoracic diseases and acute pulmonary infections, there may also be signs of pulmonary artery hypertension, such as dilation of the right lower pulmonary artery with a transverse diameter ≥15mm; a ratio of its transverse diameter to the tracheal transverse diameter ≥1.07; prominent bulging of the pulmonary artery segment or a height ≥3mm; and signs of right ventricular hypertrophy, all of which serve as the main basis for diagnosing cor pulmonale. In some patients, a reduction in cardiac shadow size may be observed after heart failure is controlled.
   2. Electrocardiogram (ECG) examination The main manifestations include changes indicative of right ventricular hypertrophy, such as right axis deviation, a mean frontal axis ≥+90°, grade III clockwise rotation, Rvl+Sr5≥1.05mV, and P pulmonale. Right bundle branch block and low-voltage patterns may also be seen, which can serve as reference criteria for diagnosing cor pulmonale. In leads V1, V2, or even extending to V3, QS waves resembling old myocardial infarction patterns may appear and should be carefully differentiated. Typical cor pulmonale.
   3. Vectorcardiogram (VCG) examination The main manifestations are patterns of right atrial and right ventricular hypertrophy. As right ventricular hypertrophy progresses, the QRS axis shifts from the normal left lower anterior or posterior direction gradually to the right, then downward, and finally to the right anterior, though the terminal portion remains in the right posterior. The QRS loop evolves from counterclockwise rotation or a "figure-8" pattern to grade III clockwise rotation. The P loop is often narrow, with increased amplitude in the left and frontal plane P loops, and the maximal vector points forward, downward, left, or right. Generally, the more pronounced the right atrial hypertrophy, the more the P loop vector shifts to the right.
   4. Echocardiogram examination By measuring the right ventricular outflow tract diameter (≥30mm), right ventricular diameter (≥20mm), the thickness of the right ventricular anterior wall, and the ratio of left to right ventricular diameters (<2)，右肺動脈內徑呈qR,V5R/S<1，Rv1+Sv5=1：5mV或肺動脈幹及右心房肥大等指標，以診斷肺心病。
   5. Pulmonary impedance plethysmography and its differential waveform examination Domestic research has shown that in cor pulmonale, the amplitude of the pulmonary impedance plethysmography wave and its differential wave values are often reduced, the Q-B interval (equivalent to the right ventricular pre-ejection period) is prolonged, the B-Y interval (equivalent to the right ventricular ejection period) is shortened, and the Q-B/B-Y ratio increases. These findings have reference value for diagnosing cor pulmonale and show significant correlation with predicting pulmonary artery pressure and latent pulmonary artery hypertension after exercise, providing certain diagnostic utility.
   6. Blood gas analysis In cor pulmonale, hypoxemia or combined hypercapnia may occur during the compensatory phase of pulmonary function. During acute exacerbation: Active infection control; ensuring airway patency and improving respiratory function; correcting hypoxia. PaCO₂<60mmH、PaC0₂>50mmHg indicates respiratory failure.
   7. Blood tests Red blood cells and hemoglobin may be elevated. Whole blood viscosity and plasma viscosity may increase, and red blood cell electrophoresis time is often prolonged. During infection, the total white blood cell count and neutrophils may rise. Some patients may show changes in renal or liver function on serological tests; serum potassium, sodium, chloride, calcium, and magnesium levels may also vary, with most values (except potassium) being lower than normal.
   8. Others Pulmonary function tests are meaningful for early or remission-stage cor pulmonale patients. Sputum bacteriological examination can guide the selection of antibiotics during acute exacerbations of cor pulmonale.

   bubble_chart Diagnosis

   According to the "Diagnostic Criteria for Chronic Cor Pulmonale" revised in 1977 in China, a diagnosis can be made if the patient has chronic bronchitis, pulmonary emphysema, other pulmonary or thoracic diseases, or pulmonary vascular lesions, leading to pulmonary arterial hypertension, right ventricular hypertrophy, or right heart dysfunction, along with the aforementioned electrocardiogram and X-ray findings. Further reference can be made to vectorcardiogram, echocardiography, pulmonary impedance rheography, pulmonary function tests, or other examinations.

   bubble_chart Treatment Measures

   (1) Control of Infection Select antibiotics based on sputum culture and drug sensitivity test results. Before culture results are available, choose antibiotics according to the infection environment and Gram stain of the sputum smear. Community-acquired infections are mostly caused by Gram-positive bacteria, while hospital-acquired infections are predominantly Gram-negative. Alternatively, use broad-spectrum antibiotics that cover both types. Commonly used antibiotics include penicillins, aminoglycosides, fluoroquinolones, and cephalosporins. When using broad-spectrum antibiotics, be cautious of potential secondary fungal infections.

   (2) Maintain Airway Patency and Correct Hypoxia and Carbon Dioxide Retention

   (3) Control of Heart Failure in Pulmonary Heart Disease The treatment of heart failure in pulmonary heart disease differs from that in other heart diseases. Patients with pulmonary heart disease often show improvement in heart failure after active infection control and respiratory function enhancement. However, for those who do not respond to treatment or have severe symptoms, diuretics, positive inotropic agents, or vasodilators may be appropriately used.

   1. **Diuretics** Diuretics reduce blood volume, alleviate right heart load, and eliminate edema. In principle, mild, low-dose diuretics should be preferred. For example, hydrochlorothiazide (25mg, 1–3 times daily) is generally used for no more than 4 days. If higher doses are required, 10% potassium chloride (10ml, 3 times daily) or potassium-sparing diuretics such as triamterene (50–100mg, 1–3 times daily) may be added. For grade III patients requiring urgent diuresis, furosemide (20mg intramuscularly or orally) can be used. Diuretics may lead to hypokalemia, hypochloremic alkalosis, worsening hypoxia, thickened sputum, and hemoconcentration, so preventive measures are necessary.
   2. **Positive Inotropic Agents** Due to chronic hypoxia and infection, patients with pulmonary heart disease have low tolerance to digitalis drugs, with poorer efficacy and a higher risk of arrhythmias, which differs from the treatment of general heart failure. The dose of digitalis should be small, typically about 1/2 or 2/3 of the conventional dose. Fast-acting and rapidly excreted digitalis drugs, such as strophanthin K (0.125–0.25mg) or cedilanid (0.2–0.4mg), should be selected and slowly injected intravenously with 10% glucose. Before administration, hypoxia should be corrected, and hypokalemia should be prevented to avoid toxic reactions. Tachycardia caused by hypoxemia or infection should not be used as an indicator for digitalis use or efficacy. Indications for digitalis include: (1) recurrent edema in heart failure patients with controlled infection and improved respiratory function but poor response to diuretics; (2) patients with predominant right heart failure and no obvious infection; (3) patients with acute left heart failure.
   3. **Vasodilators** Vasodilators reduce cardiac preload and afterload, decrease myocardial oxygen consumption, and enhance myocardial contractility, showing some efficacy in refractory heart failure, though not as pronounced as in other heart diseases. Specific drugs and methods can be referred to in Chapter 2 of Part 3. Vasodilators may dilate pulmonary arteries but also systemic arteries, potentially causing systemic hypotension, reflex tachycardia, decreased PaO₂, and increased PaCO₂, limiting their clinical use in pulmonary heart disease. Calcium channel blockers, ligustrazine, and nitric oxide (NO) can reduce pulmonary artery pressure without significant side effects.
   (4) Control of Arrhythmias Most arrhythmias resolve spontaneously after treating the infection and hypoxia in pulmonary heart disease. If they persist, appropriate antiarrhythmic drugs should be selected based on the type of arrhythmia.

   (V) Strengthening Nursing Care This disease is often acute, severe, and recurrent, requiring multiple hospitalizations, which places a tremendous psychological, emotional, and financial burden on patients and their families. Strengthening psychological care and boosting patients' confidence in treatment, as well as their cooperation with medical interventions, are crucial. At the same time, due to the complex and variable nature of the condition, close monitoring of disease progression is essential, with particular emphasis on enhancing cardiopulmonary function monitoring. Turning patients over and patting their backs to clear respiratory secretions are effective measures to improve ventilation. The management of

   lung-heart disease patients and health education have garnered increasing attention.stage of remission

   In principle, comprehensive measures integrating Chinese and Western medicine are adopted, aiming to enhance the patient's immune function, eliminate triggering factors, reduce or avoid the occurrence of acute exacerbations, and hope to gradually achieve partial or complete recovery of lung and heart function. Examples include long-term oxygen therapy and immune function adjustment.

   Nutritional Therapy

   Most patients with lung heart disease suffer from malnutrition (approximately 60-80%). Nutritional therapy helps strengthen respiratory muscle strength, improve immune function, and enhance the body's disease resistance. The caloric intake should be at least 154 kJ/kg (30 kcal/kg) per day, with carbohydrates not excessively high (generally ≤60%), as high respiratory quotient from sugar can increase respiratory load due to excessive CO₂ production. Protein intake should be 1.0–1.5 g/kg per day.

bubble_chart Prognosis

Lung heart disease often experiences repeated acute exacerbations, with the condition gradually worsening as lung function deteriorates. The prognosis is generally poor, with a mortality rate of approximately 10-15%. However, active treatment can prolong life expectancy and improve the patient's quality of life.

bubble_chart Prevention

The primary focus is on preventing diseases of the bronchi, lungs, and pulmonary blood vessels that can lead to this condition.

1. Actively implement various measures (including public awareness campaigns and effective smoking cessation medications) to promote quitting smoking.
2. Proactively prevent and control the inducing factors of primary diseases, such as respiratory infections, various allergens, and the inhalation of harmful gases.
   Conduct protective work and personal hygiene education for dust-related operations.
3. Carry out various forms of mass sports activities and health education to enhance public health knowledge and improve disease resistance.
   capacity.

bubble_chart Complications

1. Pulmonary encephalopathy is a syndrome caused by hypoxia and carbon dioxide retention due to respiratory failure, leading to mental disorders and neurological symptoms. However, it must be differentiated from conditions such as cerebral arteriosclerosis, severe electrolyte imbalances, simple alkalosis, and infectious toxic encephalopathy. It is the primary cause of death in pulmonary heart disease and requires active prevention and treatment.
2. Acid-base imbalance and electrolyte disorders In pulmonary heart disease with respiratory failure, hypoxia and carbon dioxide retention occur. When the body's compensatory mechanisms are maximized but still fail to maintain internal balance, various types of acid-base imbalances and electrolyte disorders can arise, exacerbating respiratory failure, heart failure, and arrhythmias. Monitoring and timely therapeutic interventions are crucial for treatment and prognosis.
3. Arrhythmias These often manifest as atrial premature contractions and paroxysmal supraventricular tachycardia, with chaotic atrial tachycardia being the most characteristic. Atrial flutter and atrial fibrillation may also occur. In rare cases, acute severe myocardial hypoxia can lead to ventricular fibrillation or even cardiac arrest. It is important to differentiate these from arrhythmias caused by digitalis toxicity.
4. Shock Shock is relatively uncommon in pulmonary heart disease, but when it occurs, the prognosis is poor. Causes include: (1) septic shock; (2) hemorrhagic shock, often caused by upper gastrointestinal bleeding; (3) cardiogenic shock, resulting from severe heart failure or arrhythmias.
5. Gastrointestinal bleeding
6. Disseminated intravascular coagulation (DIC).

bubble_chart Differentiation

This disease needs to be differentiated from the following diseases:

1. **Coronary atherosclerotic heart disease (referred to as coronary heart disease, CHD)** and **lung heart disease** are both common in the elderly and share many similarities, often coexisting. CHD is characterized by typical **angina pectoris**, a history of **myocardial infarction**, or electrocardiographic manifestations. A history of **left heart failure**, **primary hypertension**, **hyperlipidemia**, or **diabetes mellitus** further aids in differentiation. Physical examination, X-ray, and electrocardiographic findings predominantly showing **left ventricular hypertrophy** can help distinguish the two. When **lung heart disease** coexists with CHD, differentiation becomes more challenging and requires detailed medical history, physical examination, and relevant cardiac and pulmonary function tests.
2. **Rheumatic valvular heart disease (Rheumatic heart disease)** involving the **tricuspid valve** should be differentiated from **relative tricuspid insufficiency** in **lung heart disease**. The former often has a history of **rheumatic arthritis** and **myocarditis**, with other valvular lesions such as **mitral valve** or **aortic valve** involvement. X-ray, electrocardiography, and echocardiography show specific manifestations.
3. **Primary cardiomyopathy** typically presents with **generalized cardiac enlargement**, no history of chronic respiratory diseases, and no X-ray evidence of **pulmonary arterial hypertension**.