Usefulness of Three-Dimensional Transthoracic Echocardiographic Planimetry in a 4-Month-Old Infant with Comorbid Aortic Stenosis and Coarctation of the Aorta Complicated with Low Left Ventricular Ejection Fraction

• Comorbid valvular AS, CoA, and LV dysfunction can complicate the order of interventions. • Continuity equation cannot be used to assess AS severity in the setting of decreased LVEF. • 3D-TTE planimetry can evaluate AS severity in infants with good acoustic windows.