Abstract 13585: Non-Circular Shape of Right Ventricular Outflow Tract: A Real-Time Three-Dimensional Transesophageal Echocardiography Study
Introduction: The shape of the right ventricular outflow tract (RVOT) has been assumed to be circular. The aim of this study was to assess RVOT morphology using real-time three-dimensional transesophageal echocardiography (3D TEE).
Methods: This prospective study included 114 patients who underwent 3D TEE. 2D TEE measured maximum and minimum RVOT diameters (RVOTD max and min) during a cardiac cycle. 3D TEE assessed RVOT geometry (Figure A), and determined RVOT area max and min, RVOT fractional area change, and RVOT shape index (Vertical RVOTD / Horizontal RVOTD; Figure A). Cardiac output (CO) was measured with a Swan-Ganz catheter, 2D TEE, and 3D TEE in 20 patients. All patients were classified into Group 1 (RVOT shape index ≤1) or Group 2 (RVOT shape index >1) on a basis of the RVOT shape (Figure B).
Results: Mean RVOT area max and min, and RVOT fractional area change by 3D TEE were 6.5 ± 1.9 cm2, 3.8 ± 1.4 cm2, and 41.7 ± 12.6%, respectively. Mean RVOT shape index were 0.84 ± 0.21 at max (range 0.52-1.43) and 0.82 ± 0.20 at min (range 0.50-1.48). 2D TEE, compared with 3D TEE, underestimated RVOTD max (p<0.001). CO determined by 3D TEE (4.6 ± 1.5 L/min) had better agreement with CO determined by a catheter (4.5 ± 1.5 L/min) than 2D TEE (4.2 ± 1.3 L/min) (r = 0.83 and 0.53, respectively). As for the shape of RVOT, circular RVOT (RVOT shape index: 0.95-1.05) was found only 17 pts (14.9%). Additionally, 82 pts (71.9%) were categorized into Group 1, while 32 pts (28.1%) into Group 2.
Conclusions: 3D TEE revealed that RVOT geometry was not generally circular but oval with 2 different types. Because of the detailed morphological information of RVOT, 3D TEE could provide more accurate assessment of CO than 2D TEE.
- © 2011 by American Heart Association, Inc.