[The heart in lung diseases].

Adaptation of the heart to the disturbed gas exchange function in chronic diseases of the lung consists of hypertrophy of the right ventricle (cor pulmonale). Prognosis of the chronic cor pulmonale depends on the degree of the pulmonary hypertension. Chronic obstructive diseases of the lung (COLD) are, in accordance with their widespread occurrence, the most frequent contributing causes to the development of chronic cor pulmonale. Sleep apnoea can also lead to pulmonary hypertension, independent of COLD. The diagnostic value of measurement of pulmonary arterial pressure at rest and under stress, compared with noninvasive examination methods such as echocardiography or radionuclide venography, remains indubitable. Treating the underlying pulmonary disease is the therapy of choice. Long-term O2 therapy is the only safely established cardiac therapeutic principle in hypoxaemic patients that prolongs survival times.