Correlation study of left atrial pressure and pulmonary rheogram.

In order to observe correlations between LAP and PRG data, we placed small inflated balloons in the left atria of dogs to change LAP. We found good correlations between LAP and Q-6 interval (r = 0.88, P less than 0.001), b-s interval (r = -0.78, P less than 0.001), Hs (r = -0.59, P less than 0.001), Hs X b-s interval (r = -0.65, P less than 0.001), and HD/Hs (r = 0.50, P less than 0.001). The mechanisms of change of these parameters were investigated and corresponding regression equations derived. The authors point out that D wave enlargement and HD/Hs increase are determinant indices of LAP elevation and may be used to estimate LAP and to differentiate LAP elevation from simple pulmonary hypertension. Therefore, we conclude that PRG may reflect changes of pressure or volume in the pulmonary vein and thus provide a noninvasive method of monitoring cardiac preload and the pulmonary cycle. In addition, this research may provide the experimental basis for employing PRG in the study of such pathological processes as mitral valve lesion, left heart failure, etc.