Transthoracic echocardiography (TTE) is the most common type of cardiac echocardiography exam. The examination can be performed on a cooperative, awake patient, but the images are complicated by patient size, bone, soft tissue, and lung tissue interactions. As a result, the ultrasound beams from the transducer head must be aimed through “acoustic windows” in the thorax to image the heart. There are four typical acoustic windows; the parasternal, apical, subcostal, and suprasternal notch (Figure 1). The parasternal window is typically used for 2 chamber, long-axis views and short axis views of the heart. The apical window is typically used for the standard 4 chamber, long-axis view. The subcostal window is particularly useful for patients with lung disease or recent open-heart surgery and provides good views of major vascular connections to the heart and the interatrial septum. The suprasternal window is valuable for aortic root imaging.

Transesophageal echocardiography (TEE) involves the placement of an echocardiography transducer into the esophagus or the stomach of an anesthetized patient. This placement eliminates the need to use acoustic windows, minimizes interference from the lungs, and increases the resolution of the images obtained, due to the closer proximity of the transducer to the heart. TEE is useful for intraoperative monitoring of anesthetized patients and is used for patients in which TTE did not produce quality images.

Intracardiac echocardiography (ICE) provides better resolution than either TTE or TEE (see Figure 2 for images of transducers). The echocardiography transducer is placed into a vein and advanced through the superior vena cava into the right atrium. By placing the transducer directly into the heart, higher frequencies of sound waves can be used, creating excellent spatial resolution.