Comparison of the effect on right atrial pressure of abdominal compression versus the Valsalva maneuver.

When the right atrial pressure (RAP) exceeds the left atrial pressure, right-to-left shunting can occur. Normally, the Valsalva maneuver is used to facilitate elevation of RAP. However, performing the Valsalva maneuver can be problematic in certain situations. The aim of this study was to test the hypothesis that the application of abdominal pressure would increase the pressure within the right atrium compared with the left atrium, making it an adequate alternative to the Valsalva maneuver. Twelve patients were prospectively evaluated during right-sided cardiac catheterization with the application of abdominal pressure as well as a Valsalva maneuver. RAP and left atrial pressure were measured simultaneously. In 11 patients, the mean RAP was lower than the mean pulmonary capillary wedge pressure at baseline. The mean RAP was significantly higher than the mean pulmonary capillary wedge pressure during abdominal compression (24.8 ± 9.9 vs 21.6 ± 8.8 mm Hg, p = 0.001). When the Valsalva maneuver was performed, mean RAP was also significantly higher than the mean pulmonary capillary wedge pressure (25.3 ± 10.9 vs 22.1 ± 10.3 mm Hg, p = 0.008). In conclusion, abdominal compression is similar to an optimal Valsalva maneuver for increasing RAP and thus the right-to-left pressure gradient. Performing abdominal compression provides a simple alternative to the Valsalva maneuver for creating a transient increase in RAP.