Small-Airways Function in Myocardial Infarction

Small-airways function was measured by closing volumes in 40 patients after uncomplicated acute myocardial infarction who had no evidence of congestive heart failure by physical or radiologic examination. Mean value for closing volume was 125 per cent predicted in 25 patients studied in the first two weeks after infarction as opposed to a mean value of 104 per cent in 14 patients studied in the second two-week period after infarction (p<0.01). Seven patients with elevated closing volumes in the first two weeks after infarction had normal values when re-evaluated four to 12 months later. Acute diuresis with furosemide reduced the elevated closing volumes to normal in two patients studied in the first week after infarction. These findings suggest the occurrence, even in uncomplicated myocardial infarction, of transient left ventricular failure with pulmonary vascular congestion and transudation of fluid into the interstitial space, leading to premature airway closure. (N Engl J Med 290:761–765, 1974)