**2. Indication, contraindication, and complications**

TEE has proven to be an invaluable tool for patients underwent cardiac surgery and cardiac catheterization for congenital heart disease. More than that, TEE is useful for high risk congenital heart disease patients who will have non-cardiac surgeries. It can help with hemodynamic monitoring, and provide real-time detailed anatomic information. In addition, it can help assess ventricular volume and function, intracardiac shunt, valvular disease, right ventricle (RV) or pulmonary artery (PA) systolic pressure, and pericardial effusions. It is reasonable to use intraoperative TEE routinely in congenital heart surgery (Randolph et al., 2002). According to the "practice guidelines for perioperative TEE", TEE should be used in all adult open heart procedures (Thys et al., 2010). The task force of American Society of Echocardiography also described surgery for congenital heart disease is an indication for performance of TEE (Ayres et al., 2005).

Perioperative TEE exam cannot replace the preoperative diagnostic exam. A thorough imaging study must be performed before the operation. Each imaging study has its limitation. TEE performed before surgical incision may disclose a different diagnosis and even result in cancellation of the operation (Huang et al., 2009).

However, there are some situations that TEE is contraindicated. Patients with unrepaired tracheoesophageal fistula, esophageal obstruction or stricture, perforated hollow organ, or

Intraoperative Transesophageal Echocardiography for Congenital Heart Disease 117

Ostium primum ASD is also known as partial atrioventricular canal defects (see below). It is located in the inferior portion of the interatrial septum. It can be visualized in midesophageal four- chamber view (Figure 2). Incomplete formation of the septum primum is

Sinus venosus ASD occurs near the superior vena cava (SVC) or inferior vena cava (IVC) entrance. This kind of defect is often associated with partial anomalous pulmonary venous drainage. After surgical repair, we should look not only for the residual shunt, but also the

Coronary sinus defects are rare, and result from a communication between the left atrium

Preoperative TEE exam should confirm the location, size, shunt magnitude and direction, atrioventricular(AV) valve competence, RA and RV size, associated anomalies, and ventricular function. Post-bypass TEE exam should evaluate the adequacy of surgical repair,

and coronary sinus. They are commonly associated with a persistent left side SVC.

Fig. 2. Mid-esophageal four-chamber view demonstrates a primum atrial septal defect (arrow). RA, right atrium; RV, right ventricle; LA, left atrium; LV, left ventricle.

sometimes associated with anterior mitral leaflet cleft and regurgitation.

unobstructed flow in SVC, IVC, and pulmonary veins (Figure 3).

valvular competence, and ventricular function.

poor airway control should consider transthoracic echocardiography or epicardial echocardiography instead. Besides, patients with history of esophageal surgery, esophageal varices or diverticulum, gastric or esophageal bleeding, oropharyngeal pathology, severe coagulopathy, cervical spine injury or anomaly require extra attention for TEE probe insertion. Although TEE examination is semi-invasive, some people do suffer from complications related to TEE probe insertion (Huang et al., 2007). These include bradycardia due to vagal stimulation, oropharyngeal injury, and esophageal perforation (Kamra et al., 2011). Besides, airway compromise, vascular compression, and dysphagia may be seen after TEE probe insertion. Physicians should respect individual differences and be vigilant to possible complications.
