| 摘要 |
<p>A non-invasive apparatus for obtaining a quantitative determination of mean left atrial pressure comprises a balloon (24) to be inserted by means of a catheter (20) into the esophagus (26) and positioned adjacent the left atrium. As the balloon is gradually inflated, a tracing of mean balloon pressure is obtained. In addition, a tracing of balloon pressure on a steady baseline and with low frequency oscillations due to respiration filtered out is obtained whereby the tracing represents balloon pressure oscillations effected by left atrial pressure. In accordance with the oscillometric principle the mean balloon pressure is measured at the time when the amplitude of the balloon pressure oscillations effected by the left atrial pressure is at a peak. This mean balloon pressure is indicative of approximate mean left atrial pressure. Mean left atrial transmural pressure may be determined by subtracting therefrom the mean esophageal pressure as measured at a position in the esophagus where it is unaffected by the heart.</p> |
