NONINVASIVE ASSESSMENT OF RIGHT-VENTRICULAR DIASTOLIC FUNCTION BY ELECTRICAL-IMPEDANCE TOMOGRAPHY

Study objectives: Electrical impedance tomography (EIT) offers the pos sibility to study blood volume changes within the light atrium during the cardiac cycle. The aim of this study was to determine the applicab ility of EIT in the assessment of light ventricular diastolic function in COPD. Design:By means of region of interest analysis, impedance ch anges within the right atrium during the cardiac cycle were plotted as a function of time, As a diastolic index of the light ventricle, die light atrium emptying volume (RAEV), defined as tile ratio between the volume change during tile rapid filling phase relative to the total v entricular filling volume, was calculated, In a first study, the valid ity of the EIT method was assessed by comparison of the RAEV measured by EIT and MRI in a group of eight patients with severe COPD and seven control subjects. A second study was undertaken to assess the relatio n between RAEV and pulmonary artery pressure in a group of 27 patients measured by right-sided heart catheterization. Results: The correlati on coefficient between RAEV measured with MRT and EIT was 0.78. The di fference between RAEV measured by MRI and EIT was 8.3+/-15.7% (mean+/- SD) for the control subjects and 3.5+/-10.9% for the COPD patients, RA EV values measured by EIT and MRI were larger in the control group (47 .1+/-7.6%) compared with die patient group (38.1+/-10.4%). There mas a clear nonlinear relationship between RAEV and the pulmonary artery pr essure (y=315 x(-0.64), r=0.83, p <0.001). Conclusion: Our results ind icate that RAEV measured by EIT is a useful noninvasive and inexpensiv e method for assessing light ventricular diastolic function in COPD pa tients.