Author + information
- Received January 20, 1992
- Revision received August 14, 1992
- Accepted August 19, 1992
- Published online March 1, 1993.
- Fred M. Kusumoto, MD∗,1,
- Isobel A. Muhiudeen, MD, PHD,
- Helmut F. Kuecherer, MD2,
- Michael K. Cahalan, MD and
- Nelson B. Schiller, MD, FACC
- ↵∗Address for correspondence: Fred M. Kusumoto, MD, University of California, San Francisco, Moffitt Hospital M-1186 No. 0214, 505 Parnassus Avenue, San Francisco, California 94143-0214.
Objectives. We hypothesized that the directional movement of the interatrial septum and its curvature may reflect the pressure relations between the left and right atria.
Background. Interventricular septal shape is primarily dependent on the pressure gradient between the left and the right ventricle. No analogous study has carefully evaluated the determinants of interatrial septum shape and motion.
Methods. Patients (n = 52) undergoing cardiac or vascular surgery were studied intraoperatively at multiple intervals with transesophageal echocardiography and simultaneous measurement of central venous pressure, pulmonary capillary wedge pressure and airway pressure.
Results. Overall interatrial septum shape, which usually curved toward the right atrium, changed concordantly with the interatrial pressure gradient (pulmonary capillary wedge pressure-central venous pressure difference). The degree of interatrial septum curvature was also primarily dependent on the interatrial pressure gradient and, to a lesser extent, was affected by changes in left atrial size (F = 130.4 vs. F = 14.1). During passive mechanical expiration, the interatrial pressure gradient, usually positive, often reverses transiently and the interatrial septum momentarily bows toward the left atrium. Midsystolic reversal was seen in 64 of 72 episodes when the pulmonary capillary wedge pressure was ≤15 mm Hg but in only 2 of 40 episodes when it was >15 mm Hg (sensitivity = 0.89, specificity = 0.95, positive predictive value = 0.97).
Conclusions. These findings suggest that overall interatrial septum shape depends on the pressure gradient between the left and right atria. Midsystolic reversal of the interatrial septum, which probably reflects the increased venous return in the right relative to the left atrium during mechanical expiration, may be a useful indicator of the pulmonary capillary wedge pressure.
↵1 Dr. Kusumoto is supported in part by Grant HL07192 from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
↵2 Dr. Kuecherer is supported in part by the Deutsche Forschungsgemeinschaft (DFG 644/1-1), Heidelberg, Germany.
☆ This study was presented in part at the 63rd Scientific Sessions of the American Heart Association, Dallas, Texas, November 1990.
☆☆ All editorial decisions for this article, including selection of referees, were made by a Guest Editor. This policy applies to all articles with authors from the University of California, San Francisco.
- Received January 20, 1992.
- Revision received August 14, 1992.
- Accepted August 19, 1992.