[Vagus mediated elevation of respiratory resistance in patients with acute myocardial infarction].

Changes in pulmonary function have been reported in patients after uncomplicated myocardial infarction, with reduction in lung volumes and flow rates. The significant increase in oscillatory resistance and impedance of the lung, was seen on the first day after myocardial infarction. The application of ipratropiumbromid, an anticholinergic broncholytic agent, significantly decreased oscillatory resistance and impedance, on the first day, but not to the same extent, after the fourth day. The reduction of oscillatory resistance and impedance could be attributed to blockade of a vagal mediated bronchoconstriction, which predominantly affects the small airways. The observed changes in pulmonary function, could therefore not only be due to congestion with increase in extravascular pulmonary fluid, but in the acute phase of myocardial infarction, also due to a reflex mechanism in which vagal mediated bronchoconstriction is demonstrated.