cor pulmonale (right heart failure) is defined as an alteration in the structure and function of the right ventricle caused by a primary disorder of the respiratory system. pulmonary hypertension is the common link between lung dysfunction and the heart in cor pulmonale. right-sided ventricular disease caused by a primary abnormality of the left side of the heart or congenital heart disease is not considered cor pulmonale, but cor pulmonale can develop secondary to a wide variety of cardiopulmonary disease processes.
[color=#af0000]t[color=#af0000]he pathophysiology of cor pulmonale is divided to two:
1. mechanism of pulmonary hypertension , under this is
a. hypoxia and acidosis - the vasoconstrictive effect of hypoxia is a potent stimulus for hypertension. this mechanism may be augmented by acidosis which has also an effect on the pulmonary vasculature.
b. obliteration or obstruction of the pulmonary vascular bed - substantial loss of the pulmonary vascular bed can result from emphysema.
2. development of cor pulmonale - this is as follows:
a. although acute hypoxia elicits approximately the same pressor response, each bout of pulmonary hypertension predisposes the patient to progressively higher levels of residual hypertension after recovery.
b. the resultant sustained pulmonary hypertension causes smooth muscle hypertrophy in the pulmonary arteries and then in the peripheral pulmonary vessels. the pulmonary vascular bed becomes more rigid and less reactive to changes in cardiac output.
c. this, in turn, affects the performance of the right ventricle, causing right ventricular hypertrophy and right-sided heart failure (i.e., cor pulmonale).
in chronic cor pulmonale, rv hypertrophy (rvh) generally predominates. in acute cor pulmonale, right ventricular dilatation mainly occurs. the rv is a thin-walled chamber that is more a volume pump than a pressure pump. it adapts better to changing preloads than afterloads. with an increase in afterload, the rv increases systolic pressure to keep the gradient. at a point, a further increase in the degree of pulmonary arterial pressure produces significant rv dilatation, an increase in rv end-diastolic pressure, and rv circulatory collapse.
a decrease in rv output with a decrease in diastolic left ventricle (lv) volume results in decreased lv output. because the right coronary artery, which supplies the rv free wall, originates from the aorta, decreased lv output diminishes blood pressure in the aorta and decreases right coronary blood flow. what ensues is a vicious cycle between decreases in lv and rv output.
physical findings may reflect the underlying lung disease or pulmonary hypertension, right ventricular hypertrophy (rvh), and rv failure. an increase in chest diameter, labored respiratory efforts with retractions of the chest wall, distended neck veins with prominent a
waves, and cyanosis may be seen.
the heart and lung are intricately related. whenever the heart is affected by disease, the lungs will follow and vice versa. pulmonary heart disease is by definition a condition when the lungs cause the heart to fail.
the heart has two pumping chambers. the left ventricle pumps blood throughout the body. the right ventricle pumps blood to the lungs where it is oxygenated and returned to the left heart for distribution. in normal circumstances, the right heart pumps blood into the lungs without any resistance. the lungs usually have minimal pressure and the right heart easily pumps blood through.
cor pulmonale - wikipedia, the free encyclopedia
however when there is lung disease present, like emphysema, chronic obstructive lung disease (copd) or pulmonary hypertension, the small blood vessels become very stiff and rigid. the right ventricle is no longer able to push blood into the lungs and eventually fails. this is known as pulmonary heart disease. pulmonary heart disease is also known as right heart failure or cor pulmonale. the chief cause of right heart failure is the increase in blood pressure in the lungs (pulmonary artery).
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