What are the limitations of TTE?

The modality depends on an adequate echocardiographic window. Imaging may be poor in patients with obstructive lung disease because ultrasound transmission through air is poor. Calcified or metallic substances (e.g., the rib cage, prosthetic heart valves) may block ultrasound transmission and cause shadowing. In some patients with a poor window it may be helpful to have them lean forward during the exam to bring more of the heart in contact with the chest wall.