Cardiac and pulmonary diseases. A pathophysiologic interelationship.

Left heart diseases, in particular mitral stenosis, are often associated with anatomic and functional alterations of the lung. According to the pulmonary structures involved they could be named chronic secondary intersticial and vascular lung diseases. Congenital heart diseases with pre- or post-tricuspid shunts are also often associated with anatomic and functional alterations of the lung. This condition also constitutes a chronic secondary vascular lung disease (atrial septal defect) or a chronic primary vascular lung disease ( ventricular septal defect, patent ductus arteriosus). Primary lung diseases (interstitial pulmonary fibrosis, pulmonary emphysema, recurrent pulmonary embolism) are often associated with right ventricular hypertrophy with or without dilation, a condition commonly named chronic cor pulmonale. On the whole the interrelationships between heart and lung diseases are as follows: a) anatomic and functional alterations of the lung due to left heart diseases are mediated through pulmonary venous hypertension; b) anatomic and functional alterations of the lung due to congenital heart diseases are mediated through the increased pulmonary blood flow with or without transmission of the systemic blood pressure to the pulmonary vasculature, and c) anatomic and functional alterations of the right ventricle due to primary or secondary lung diseases are mediated through arterial pulmonary hypertension. In summary, the interrelationships between heart and lung diseases are mainly mediated through the pulmonary venous or pulmonary arterial hypertension.