• OBJECTIVE
    • To compare the determination of stroke volume (SV) and cardiac output (CO) using 2-dimensional (2D) versus 3-dimensional (3D) transesophageal echocardiography (TEE).
  • DESIGN
    • Prospective observational study.
  • SETTING
    • Tertiary care university hospital.
  • PARTICIPANTS
    • 35 patients without structural valve abnormalities undergoing isolated coronary artery bypass grafting.
  • INTERVENTIONS
    • Left ventricular outflow tract (LVOT) diameter determined with 2D TEE was used to estimate LVOT cross-sectional area (CSALVOT). LVOT area was measured directly with 3D TEE by planimetry on an en face view. SV and CO were calculated for both methods using the continuity equation.
  • MEASUREMENTS AND MAIN RESULTS
    • The area of the LVOT differed significantly between methods, being significantly larger in the 3D method (3.57±0.70 cm(2)v 3.98±0.93 cm(2)) . This resulted in a 10% lower CO with the 2D method of LVOT area estimation.
  • CONCLUSIONS
    • LVOT area is underestimated with the single- axis 2D method when compared with 3D planimetered area. This results in a CO that is approximately 10% lower with the 2D method.