Car pulmonale or pulmonary hcart disease is a telm that describes the pathologic effects of lung dysfunction on the right side of the heart. PAH is the link between lung dysfunction and the heart in cor pulmonale. Pullnonay heart disease (cor pulmonale) occurs as a late lnanifestation of many diseascs of the lung, but the common thread in each case is incrcascd RV after load. The prcsence of over1 right sided heart failure is not essential to make the diagnosis of cor puln~onale, but right sided heart lailure is common consequence. Right ventricular hypertrophy and dilatation appear earlier than failure.Other causes of PAH as discussed carlier (secondary to PVI-I, shunt lesions,thro~nboembolic PAH) and PPT-I will not be discussed in this section.
a) Causes
The comnlon causes are given below:
a) Causes
The comnlon causes are given below:
b) Symptoms
Clinical manifestations of cor pulmonale are often obscured by the signs and symptoms of underlying disease and therefore are closely related to the pulmonary disease or disorder. It is necessary first to recognize the type and severity of lung disease and then to look for cor pulmonale.There is no history that is specific for cor pulmonale. Shortness of breath is nearly a universal symptom. The degree of activity that leads to dyspnea should be quantified because patients reduce activities to avoid dyspnea. Episodes of leg edema, atypical chest pain, exercise induced peripheral cyanosis, prior respiratory failure, and excessive daytime somnolence are all historical clues. Chest pain may be due to strain or distortion of the chest wall (musculoskeletal) or may be related to right ventricular ischemia. Cough and complaints of easy fatigability are comn~on. Some patients with nocturnal hypoventilation and sleep apnea may present with personality changes, mild systemic hypertension, and headache. Abdominal pain may result from liver and bowel congestion if RVF is present.
c)Clinical Features
Signs suggestive of heart failure such as dyspnea, orthopnea, peripheral edema,palpable liver, and distended neck veins can be observed in patients with COPD without RVF. But when neck pains are distended during inspiration as well as expiration. RVF is more likely present. Hyperinflated lungs alter the position of the heart and frequenlly make the examination difficult. The apical impulse and the right ventricular lift are often not palpable, and the right ventricular S3 gallop may be heard in the epigastrium. In emphysema, the heart sounds may be best heard in the subxiphoid area. Extremities may be warn1 due to peripheral vasodilatation caused by hypercapnia, or there may be cyanosis due to low flow or hypoxemia. All the signs of PAH as described in earlier sections are present in majority of cases.
Investigations
1)Chest Roentgenogram
The radiographic findings of pulmonary hypertension in patients with normal lung parenchyma (such as in PPH) are well described. Most diseases h a t cause cor pulmonale have grossly abnormal chest roentgenograms, and the radiologic diagnosis of PAH in these diseases is more difficult. Right ventricular enlargement may be difficult to detect in the vertical heart of emphysema, and comparison with previous films may be helpful. The lungs may show features of emphysema, fibrosis or bronchiectasis.
2) Electrocardiogram
Electrocardiographic patterns are influenced by many factors such as PAP, rotation, and displacement of the heart by hyperinflated lungs, arterial blood gases,myocardial ischemia, and metabolic disturbances .The value of the ECG in diagnosis of cor pulmonale, therefore, depends on the underlying disease and complicating conditions. Absence of changes indicating right ventricular disease does not rule out cor pulmonale because the ECG may be normal in advanced cor pulmonale. Tall peaked P waves in leads I1 and AVF may reflect positional changes rather than right atrial enlargement. Right bundle branch block bccurs in about 15 per cent of patients. A pattern of S 1, 43, and T3 carries reasonable sensitivity and specificity for cor pulmonale in COPD. Arrhythmias are infrequent in uncomplicated cor pulmonale, but when present, they are mostly supraventricular and may reflect blood gas abnormalities, hypokalemia, or excess of drugs such as digitalis, tl~eophyline, and beta agonists. Ventricular arrhythmias, when present are associated with a high mortality.Diseases of the Lungs a ~ ~ d Pulmonary Circulation
3) Echocardiography
The presence of chronic obstructive or restrictive lung disease often distorts cardiac anatomy and makes echocardiographic evaluation of right heart chambers difficult.Advances in echocardiography (2DE, subcostal views, transesophaygeal echocardiography) have facilitated better assessment of right ventricular chamber size and wall thickness, as well as changes in the intraventricular spetum resulting from RVH. Because the right ventricle is asymmetric, measurement of righl ventricular volume is difficult even with two dimensional views. Right ventricular pressure ,overload usually is detected by hypertrophy of the anterior right ventricular wall and by dilatation of the chamber. Hypertrophy of the septum can be found, and paradoxical septa1 encroachment into the left ventricular chamber can be seen in severe cor pulmonale. Right velltricular volulne overload and abnormal ventricular septa1 motion occur with advent of tricuspid and pulmonary regurgitation.Doppler techniques have become the non-invasive method to assess degree of PAH and other haemodynamic variables.
Arterial Blood Gases (ABG)
Ailalysis of blood gases for PH, PO,, PCO, is important in guiding therapy. It is common to see reduction in oxygen saturation, oxygen content Po2 and variable increase in PCO,. There can be respiratory or metabolic acidosis or alkalosis depending on associated metabolic factors.
Pulmonary Function Test (PFT)
I Spirometry, lung volumes (functional residual capacity) and other PFT will reveal the nature and degree of impairment of lung function. PFT studies often show reduction in FEVl (forced expiratory volume in first second) and in forced vital capacity
(FVC). The residual volume is increased and total lung volume is normal.
Other tests
CTz scan is often required to delineate nature of lung disease and CTPA may be needed to exclude PE. Lung biopsy is rarely needed to diagnose conditions like sarcoidosis or tuberculosis.
Management
The underlying lung disease is the focus of therapy and is the best way to reduce the light ventricular pressure work associated with the disease. Any exposure 10 smoke (smoking), dust or toxic agents should be avoided. If RVF has not appeared, a major goal is to prevent its onset. When it appears, it should be treated but the response will be poor unless cardiac work is reduced by control of pulmonary hypertension.
Treatment to Decrease Pulmonary Hypertension
Relief of hypoxia is of prime impol-tance in reducing pullnonary hypertension, both to prevellt and to treat cor pulmonale. This may be done in two ways: (1) treatment of the underlying disease, and (2) 0, administration. Neither will lower PAP in all patients because hypertension is often intractable in those with an anatomic restriction of the pulmonary vascular bed. Most patients with chronic cor pulmonale have a component of hypoxic pulmonary vasoconstriction, and all patients should be treated with oxygen in amounts adequate to restore arterial tension to greater than 60 m m ofHg. Corticosteroids may be helpful in some patients with interstitial lung disease and in patients with a bronchospastic component of COPD. Measures should be instituted to treat the systemic disease with which obliterative vascular disease is associated.
In COPD, the primary focus is relief of hypoxemia by restoration of effective ventilation or by 0, administration. Net alveolar ventilation may be improved by therapy, including bronchodilators for bronchospasm, antibiotics to prevent or treat acute exacerbations of bronchitis, bronchial toilet for removal of secretions, and avoidance of aiiway irritants such as tobacco smoke. Nocturnal aspiration of gastric fluid is now known to be a common cause of exacerbation of chronic lung disease. Tranquilizers, sedatives, and narcotics should be avoided in unstable patients and patients with hypoventilation. Correction of hypoxia and acidosis may produce a striking reduction in PAP. In diseases that alter lung function but not structure, effective alveolar ventilation must be restored by treatment of the underlying disease or by use of mechanical ventilation. Short-teim ventilatory stimulants may be useful
in some cases of decreased ventilatory drives, although nasal CPAP has become the first choice in most cases of sleep apnea.
Arterial Blood Gases (ABG)
Ailalysis of blood gases for PH, PO,, PCO, is important in guiding therapy. It is common to see reduction in oxygen saturation, oxygen content Po2 and variable increase in PCO,. There can be respiratory or metabolic acidosis or alkalosis depending on associated metabolic factors.
Pulmonary Function Test (PFT)
I Spirometry, lung volumes (functional residual capacity) and other PFT will reveal the nature and degree of impairment of lung function. PFT studies often show reduction in FEVl (forced expiratory volume in first second) and in forced vital capacity
(FVC). The residual volume is increased and total lung volume is normal.
Other tests
CTz scan is often required to delineate nature of lung disease and CTPA may be needed to exclude PE. Lung biopsy is rarely needed to diagnose conditions like sarcoidosis or tuberculosis.
Management
The underlying lung disease is the focus of therapy and is the best way to reduce the light ventricular pressure work associated with the disease. Any exposure 10 smoke (smoking), dust or toxic agents should be avoided. If RVF has not appeared, a major goal is to prevent its onset. When it appears, it should be treated but the response will be poor unless cardiac work is reduced by control of pulmonary hypertension.
Treatment to Decrease Pulmonary Hypertension
Relief of hypoxia is of prime impol-tance in reducing pullnonary hypertension, both to prevellt and to treat cor pulmonale. This may be done in two ways: (1) treatment of the underlying disease, and (2) 0, administration. Neither will lower PAP in all patients because hypertension is often intractable in those with an anatomic restriction of the pulmonary vascular bed. Most patients with chronic cor pulmonale have a component of hypoxic pulmonary vasoconstriction, and all patients should be treated with oxygen in amounts adequate to restore arterial tension to greater than 60 m m ofHg. Corticosteroids may be helpful in some patients with interstitial lung disease and in patients with a bronchospastic component of COPD. Measures should be instituted to treat the systemic disease with which obliterative vascular disease is associated.
In COPD, the primary focus is relief of hypoxemia by restoration of effective ventilation or by 0, administration. Net alveolar ventilation may be improved by therapy, including bronchodilators for bronchospasm, antibiotics to prevent or treat acute exacerbations of bronchitis, bronchial toilet for removal of secretions, and avoidance of aiiway irritants such as tobacco smoke. Nocturnal aspiration of gastric fluid is now known to be a common cause of exacerbation of chronic lung disease. Tranquilizers, sedatives, and narcotics should be avoided in unstable patients and patients with hypoventilation. Correction of hypoxia and acidosis may produce a striking reduction in PAP. In diseases that alter lung function but not structure, effective alveolar ventilation must be restored by treatment of the underlying disease or by use of mechanical ventilation. Short-teim ventilatory stimulants may be useful
in some cases of decreased ventilatory drives, although nasal CPAP has become the first choice in most cases of sleep apnea.
Adequate oxygenation may prevent the onset of heart failure, both acutely and over a long period of time. Any patient with cor pulmonale and RVF should be given sufficient 0, to restore PO, to levels above 60 rnmHg, but it should be given cautiously when Pco2 is high and the threat of respiratory acidosis is present. Oxygen therapy is usually well tolerated in patients with stable lung disease but not in patients with acute acidosis or respiratory muscle fatigue. When low flow nasal PO, causes increase in PCO,, mechanical ventilation may be required to relieve hypoxia. Studies have shown conclusively that home oxygen therapy, nocturnal or continuous, is beneficial in keeping patients with severe COPD functioning better for longer periods of time ; it may be effective both in lreating cor pulmonale and in postponing its onset. Continuous 24 hlday oxygen therapy is the desired goal in most patients, because desaturation occurs during both sleep and physical activity.
Treatment of Heart Failure
Cor pulmonale is heart disease, and while treatment of the lung disease and relief of hypoxia are necessary to reduce cardiac work, general principles of management of heart failure apply. Diuretics and phlebotomy can be appropriate measures for treatment of RVE Pulmonary vasodilators are efficacious in some patients with primary pulmonary hypertension but are of unproven value in cor pulmonale from COPD.
Beneficial effects of digitalis are not as obvious as obvious as in LVF, and arrhythmias caused by digitalis may occur at relatively low serum levels in patients with hypoxia and acidosis. Susceptibility to digitalis intoxication is enhanced in pulmonary disease. Its use in cor pulmonale therefore has been controversial.Nevertheless, studies have shown that digitalis improves right ventricular function in cor pulmonale, and it is an appropriate drug for treatment of RVF when given cautiously and at carefully controlled dosage levels. It should not be used during the acute phases of respiratory insufficiency when there are large fluctuations in levels of hypoxemia and acidosis but is reserved for the time when the patient is stabilized.
Surgical Treatment
There is no surgical treatment for most disease that causes cor pulmonale. Single lung, double lung and heart lung transplantation have all been used rarely. The best treatment in this group of patients remains prevention of lung disease and prevention of occurrence of PAH and subsequent heart failure.
Treatment of Heart Failure
Cor pulmonale is heart disease, and while treatment of the lung disease and relief of hypoxia are necessary to reduce cardiac work, general principles of management of heart failure apply. Diuretics and phlebotomy can be appropriate measures for treatment of RVE Pulmonary vasodilators are efficacious in some patients with primary pulmonary hypertension but are of unproven value in cor pulmonale from COPD.
Beneficial effects of digitalis are not as obvious as obvious as in LVF, and arrhythmias caused by digitalis may occur at relatively low serum levels in patients with hypoxia and acidosis. Susceptibility to digitalis intoxication is enhanced in pulmonary disease. Its use in cor pulmonale therefore has been controversial.Nevertheless, studies have shown that digitalis improves right ventricular function in cor pulmonale, and it is an appropriate drug for treatment of RVF when given cautiously and at carefully controlled dosage levels. It should not be used during the acute phases of respiratory insufficiency when there are large fluctuations in levels of hypoxemia and acidosis but is reserved for the time when the patient is stabilized.
Surgical Treatment
There is no surgical treatment for most disease that causes cor pulmonale. Single lung, double lung and heart lung transplantation have all been used rarely. The best treatment in this group of patients remains prevention of lung disease and prevention of occurrence of PAH and subsequent heart failure.
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