Background. No method has been available to assess the right ventricular (RV) pressure-volume relation in the operating room or intensive care unit. Left ventricular cross-sectional area measured by echocardiography using the technology of automated border detection has been used to construct left ventricular pressure-area (P-A) loops. In the human right ventricle, however, this approach has not been validated. Methods. We recorded RV P-A loops in 14 patients in the intensive care unit using transesophageal echocardiography. Multiple RV P-A loops were obtained by reducing preload with intravenous nitroglycerin, thereby elucidating the end-systolic P-A relation. Results. With an incremental dose of dobutamine, the slope of the RV end-systolic P-A relation increased (from 4.56 ± 2.42 to 7.34 ± 3.62 mm Hg/cm2, p < 0.01), with no change in the x-axis intercept, which implied increased contractility. Furthermore, in the operating room we validated the use of RV cross-sectional area as a surrogate for RV volume by demonstrating the close correlation between the stroke area (maximal RV area minus minimal RV area) and stroke volume (r = 0.962; p < 0.0001). Conclusions. Transesophageal echocardiography with automated border detection is a promising tool for elucidating RV function through the analysis of RV P-A loops.
All Science Journal Classification (ASJC) codes
- Pulmonary and Respiratory Medicine
- Cardiology and Cardiovascular Medicine