Cor pulmonale is defined as an alteration in the structure and function of the right ventricle of the heart as a response to a disorder of the respiratory system. The chronic form usually leads to right ventricular hypertrophy, the acute form results in dilatation.
The symptoms of cor pulmonale, pulmonary heart disease vary as the disorder progresses. Individuals may be asymptomatic in the early stages or symptoms will suggest other milder conditions. However, as the disease progresses symptoms become more severe but vary between patients. Symptoms of pulmonary heart disease may include   :
Physical indicators of cor pulmonale on exam:
The diagnosis of cor pulmonale clinically may be difficult because its symptoms are similar to those of any pulmonary or cardiac disorder. Diagnosis of pulmonary heart disease depends on the presence of both pulmonary hypertension and right ventricular hypertrophy. These two signs can be detected by the following studies   :
The diagnosis of pulmonary hypertension traditionally is depended on measurements taken during invasive cardiac catheterisation  . An increased mean pulmonary arterial pressure is characteristic of pulmonary hypertension . The development of non-invasive methods to measure pulmonary hypertension using magnetic resonance imaging imaging alone is being researched . Magnetic resonance imaging can measure mean pulmonary arterial pressure as well as evaluate vascular anatomy and blood flow patterns .
Plasma brain natriuretic peptide (BNP) may be a reliable and accurate diagnostic test for pulmonary hypertension and right ventricular dysfunction . It is a cardiac hormone which is produced by the ventricle and secreted in response to increased ventricular stretch and tension  . There is a significant correlation between brain natriuretic peptide levels and pulmonary hypertension determined by echocardiography .
Chest X-ray will show right ventricular hypertrophy, right atrial dilatation, and a prominent pulmonary artery . Pulmonary fields show reduced vasculature, hyperinflation, increased translucency of the lung and/or a flattening of the diaphragm  . Echocardiogram shows indications of right ventricular hypertrophy, right axis deviation, and mitral valve abnormalities. Findings differ from patient to patient. Two-dimensional (2-D) echocardiography may demonstrate increased right ventricle wall thickness asign of chronic right ventricular pressure overload . Doppler echocardiography can estimate pulmonary arterial pressure and is the most reliable noninvasive means to do this . High-resolution echocardiography and magnetic resonance imaging can accurately measure pulmonary pressure, however, right heart catheterization is still considered the most precise method for diagnosis and evaluation of pulmonary hypertension  .
Elimination of the cause(s) of cor pulmonale is the most important intervention  . Smoking cessation and/or elimination of exposure to second-hand smoke is the major preventive measure. Exposure to dust, toxic fumes, asbestos, toxic chemicals, and known allergens are also necessary . Treatment of the underlying causative conditions is paramount to the prevention and treatment of cor pulmonale  . The goals of interventions focus on the treatment of the underlying pulmonary disease and improving oxygenation and right ventricular function by increasing right ventricular contractility and decreasing pulmonary vasoconstriction by improving pulmonary blood flow, decreasing pulmonary vascular pressure, increasing cardiac out-put, and preventing hypoxemia and therefore prevent pulmonary vascular changes  .
Treatment regimes may include    :
Currently, long-term oxygen therapy is the primary treatment to prevent pulmonary hypertension since the major causative factor is alveolar hypoxia   . Oxygen therapy can stabilize or partially reverse pulmonary hypertension  . It is unclear if this is the result of improved oxygenation, reduced systemic inflammation or reversal or stabilization of pulmonary hypertension  .
Oxygen therapy is almost always required to prevent hypoxemia that contributes to pulmonary vascular changes and cardiac ischemia  . Oxygen at a rate of 2 litres per minute is recommended. Excessive oxygen can in patients with chronic obstructive pulmonary disease who are chronically hypoxic. Sudden correction of hypoxia can remove the main stimulus to respiration and respiratory arrest can occur   .
Treatment to prevent congestive heart failure requires diuretics, nitrates to improve cardiac out-put, and phosphodiesterase inhibitors to improve heart contractility  .
Anticoagulant therapy is recommended for all patients with primary pulmonary hypertension   . The goal of their use is to prevent thromboembolisms that are a frequent complication of pulmonary hypertension   and a common cause of death in individuals suffering from cor pulmonale  .
Inhaled nitric oxide is a potent vasodilator. It must be used in conjunction with oxygen therapy it may worsen ventilation perfusion imbalance . When it is used with oxygen there is significant improvement in pulmonary vascular resistance, pulmonary hypertension and cardiac output . Sildenafil is a phosphodiesterase 5 inhibitor specific to pulmonary function. It causes vasodilation and increases the effects of inhaled nitric oxide  .
Diuretics are used to reduce right ventricular dilatation and improve cardiac output and reduce pulmonary edema . They can cause volume depletion that decrease cardiac output so should be used cautiously . Intravenous epoprostenol (Flolan) is used to improve symptoms and survival of patients with pulmonary hypertension . It has been shown to be effective but their long-term efficacy is not known .
Bronchodilators are the primary treatment regime for COPD . They can be combined with inhaled corticosteroids for better results and fewer side effects . Nifedipine, a calcium antagonist, reduces both pulmonary and systemic vasomotor tone at rest and during exercise. It has been shown to increase resting cardiac output by 26% .
Theophylline has significant antiinflammatory effects in chronic obstructive pulmonary disease . It has been shown to restore steroid sensitivity . The use of digoxin in the treatment of cor pulmonale is controversial. Research has shown that heart failure was significantly worsened in some patients, paticularly those with atrial fibrillation, and showed no improvement in other patients .
Polycythemia, an increased number of red blood cells in response to chronic hypoxemia, is a common occurrence in chronic obstructive pulmonary disease  . This increases blood viscosity decreasing pulmonary profusion and contributing to pulmonary hypertension. When the hematocrit is greater than 60% therapeutic phlebotomies is recommended to reduce the red blood cell count . Losartan used weekly in escalating doses daily for 4 weeks caused a significant reduction in the hematocrit . This ‘bloodless phlebotomy’ appears to be a promising therapy .
Lung volume reduction surgery (LVRS) reduces hyperinflation and improves gas exchange  . It may result in better distribution of pulmonary blood flow and ventilation perfusion balance . It is an extremely invasive intervention and should be reserved after other treatments have failed. Non-pharmacologic interventions for chronic pulmonary disease include long-term oxygen therapy, nasal positive pressure ventilation, pulmonary rehabilitation, lung-volume-reduction surgery and, most important, smoking cessation .
The development of cor pulmonale is associated with poor prognosis, increased cardiac death rate, and impaired health status from chronic respiratory disease  . Two factors have been shown significant for prognosis in cor pulmonale; the pulmonary arterial oxygen saturation and the use of anticoagulant therapy . In severe chronic obstructive pulmonary disease and cor pulmonale activities of daily living, such as climbing stairs or walking, can be difficult and cause an acute episode of increased pulmonary hypertension .
Long-term oxygen therapy is the only treatment, apart from smoking cessation, that has been shown to improve survival rates in severe cases of chronic pulmonary disease and cor pulmonale . Cor pulmonale, hypoproteinemia and a high PaCO2 level have been identified as risk factors for early readmission of patients with chronic obstructive pulmonary disese . Readmission rate of about 6.8% have been reported .
Cor pulmonale and pulmonary hypertension are difficult to diagnose and to treat . Untreated it is characterized by a progressive increase in pulmonary vascular resistance leading to right ventricular failure and death . In the past decade there have been remarkable improvements in therapy for this disorder .
The heart and lungs are intricately connected. Pulmonary heart disease, by definition, indicates that the lungs cause the heart to fail  . Two major causes of cor pulmonale are changes to the pulmonary vascular from tissue damage and chronic pulmonary vasoconstriction due to chronic hypoxemia . Cigarette smoking and air pollution are the main risk factors for lung disease and the potential for developing cor pulmonale. Cor pulmonale is a progressive disease and if left untreated results in significant disability, impaired quality of life, and eventually death .
The causes of cor pulmonale include  :
It is difficult to determine the exact incidence of cor pulmonale . The reported prevalence varies depending on the definition of pulmonary hypertension, the group studied, and the method of measuring . Approximately 6-7% of all heart disease in adults in the United States is due to cor pulmonale. More than 50% of cases of cor pulmonale are due to chronic obstructive pulmonary disease (COPD), chronic bronchitis or emphysema  . The primary cause of these conditions is cigarette smoking . About 15 million people in the United States suffer from chronic pulmonary disease .
Each year there are approximately 20,000 deaths and 280,000 hospital admissions due to pulmonary heart disease . In patients experiencing pulmonary emboli who have a co-morbidity of chronic cor pulmonale the mortality rate may be as high as 17 to 30% higher than in patients with the co-morbidity .
The heart is responsible for circulating blood throughout the body with the two ventricles acting as the pumps. The left ventricle pumps blood throughout the body. The right ventricle pumps blood to the lungs where it is oxygenated and then returned to the left heart for distribution . Normally the pulmonary system offers minimal resistance. However with chronic obstructive pulmonary disease (COPD) and disorders that increase pulmonary vascular resistance, pulmonary hypertension occurs  .
The pathology of pulmonary hypertension is the result of pulmonary vascular vasoconstriction, smooth muscle cell proliferation, and thrombosis  . These changes are due to an imbalance between vasodilators (prostacyclin, nitric oxide, vasoactive intestinal peptide) and vasoconstrictors (thromboxane A2, endothelin, serotonin) . Current treatment is directed at restoring the balance between these factors .
Pulmonary hypertension is always the underlying pathology for right ventricular hypertrophy in cor pulmonale . Hypertrophy is an adaptive response to chronic hypoxia. In order to provide the force required to move blood against the greater resistance in the pulmonary vasculature the right ventricle enlarges and the musculature thickens . Acute, rather than chronic, pulmonary heart disease results in right ventricular dilatation  . Dilatation is stretching of the musculature of the ventricle as due to a sudden increase in pulmonary pressure. This occurs from a pulmonary embolism or acute respiratory distress syndrome (ARDS) . Both of these occurrences result in decreased cardiac output and eventually right sided heart failure. If left untreated either will progress to congestive heart failure and death . Several mechanisms lead to pulmonary hypertension and pulmonary heart disease including:
Pulmonary hypertension in cor pulmonale is the result of hypoxia causing pulmonary vasoconstriction, polycythemia, and pulmonary vascular bed destruction  . Pulmonary vasoconstriction is an adaptive response to divert blood from unventilated alveoli to maintain ventilation-perfusion balance and a normal PaO2   . Pulmonary vascular remodeling due to chronic ischemia causes fibrosis and proliferation of smooth muscle of small pulmonary arteries . These narrow, thickened pulmonary arteries are less compliant and increase resistance to blood flow .
In response to chronic hypoxemia the body produces an excess number of erythrocytes in an effort to increase the oxygen carrying capacity of the blood  . The resulting polycythemia increases the viscosity of the blood decreasing blood flow throught the pulmonary vasculature even further. This impairs oxygenation and contributes to pulmonary hypertension . Pulmonary hyperinflation is also associated with pulmonary hypertension. Severe emphysema causes air-trapping that may play a role in the development of pulmonary hypertension . Elevated brain natriuretic peptide (BNP) level may be a natural mechanism to compensate for pulmonary hypertension and right heart failure by promoting diuresis and natriuresis, vasodilating systemic and pulmonary vessels, and reducing circulating levels of endothelin and aldosterone.
In patients with advanced chronic obstructive pulmonary disease, oxygen saturation falls during REM sleep by 20%–30% . Nocturnal desaturation in COPD can lead to the development of pulmonary hypertension and cor pulmonale .
A majority of cases of cor pulmonale can be prevented by  :
Correction of abnormal gas exchange and ventilation through oxygen supplementation and vasodilators can decrease pulmonary hypertension. Doing this will improve survival and quality of life for those with chronic pulmonary disease .
Cor pulmonale also known as pulmonary heart disease (Latin: cor- heart; pulmōnāle- of the lungs) refers to the interconnectedness of the pulmonary and cardiac systems. It is characterized by hypertrophy and failure of the right ventricle of the heart  . The abnormalities in in the structure and function of the right ventricle in cor pulmonale occur in response to increased pulmonary vascular resistance and/or pulmonary hypertension  .
Pulmonary hypertension, a disabling chronic disorder of the pulmonary vasculature, is characterized by increased pulmonary artery pressure due to increased pulmonary vascular resistance . Pulmonary hypertension is the most common cause of cor pulmonale, but a wide variety of cardiopulmonary disease processes can cause the condition  .
The course of cor pulmonale is usually chronic and it progresses slowly . Cor pulmonale can be life-threatening if untreated. The major risk factors for lung disease are cigarette smoking and air pollution which are preventable . Elimination of cigarette smoking, second-hand smoke and air pollution could significantly decreases the incidence of cor pulmonale.
What is cor pulmonale?
Cor pulmonale refers to heart disease that results from chronic pulmonary disease. It is characterized by pulmonary hypertension, elevated pressure within the blood vessels of the lungs, and enlargement and abnormal function of the right ventricle of the heart. The most common causes of cor pulmonale are chronic obstructive pulmonary disease (COPD), emphysema, and pulmonary emboli (blood clots). If left untreated cor pulmonale will progress to heart failure and death.
What are the symptoms?
The symptoms of cor pulmonale are not specific but are similar to any heart of lung conditions. They include:
What causes cor pulmonale?
The most common causes are cigarette smoking and exposure to toxic fumes and particulates (asbestos, coal dust, chemicals). Pulmonary hypertension in cor pulmonale is the result of destruction of the cells and blood vessels of the lungs that narrows the pathways to the flow of blood. Enlargement and decreased function of the right ventricle of the heart is due to the increased work required by the right ventricle to push blood through these narrowed vessels.
Who gets cor pulmonale?
Cor pulmonale is diagnosed by the presence of pulmonary hypertension and right ventricle enlargement. Pulmonary hypertension can be detected by measuring the pressure within the pulmonary arteries. This is done using cardiac magnetic resonance imaging (MRI) and/or cardiac catherization. Right ventricular enlargement can be detected and measured using chest X-rays, electrocardiogram, and echocardiogram.
How is cor pulmonale treated?
Cor pulmonale is treated by treating the underlying pulmonary hypertension and preventing low oxygen levels and blot clot formation. Long-term oxygen therapy is the most efficient method of treatment. Other medications that may be used are hypertensive drugs, vasodilators, bronchodilators, diuretics, and anticoagulants.
What are the complications?
Complications of cor pulmonale include:
How can it be prevented?
The primary way to prevent the condition is to prevent chronic ling disease. The best way of doing this is to: