**4. Conclusion**

134 Echocardiography – In Specific Diseases

which is unable to maintain a pulmonary or systemic circulation independently (Khairy et al., 2007). This anatomical category includes hypoplastic left heart syndrome, tricuspid atresia, and double-inlet LV (Figure 19). Two-ventricular repair may not be feasible in some complex congenital heart disease even with balanced ventricles, such as malpositioned or straddling AV valve, or DORV with a remote VSD, and single ventricle management

Fig. 19. Single ventricle physiology. (A) Hypoplastic left heart syndrome. The mid-

atresia (arrow) and hypoplasia of right ventricle (RV). RA, right atrium.

obstruction both contribute to the clinical manifestation.

esophageal short-axis view shows the mitral atresia (arrow) and hypoplasia of left ventricle (LV). (B) Tricuspid atresia. The mid-esophageal short-axis view demonstrates the tricuspid

In single ventricle anatomy, the functional ventricle provides a common mixing chamber, and must pump both the systemic and pulmonary circulations, which easily lead to volume overload, cyanosis, or congestive heart failure. This pathophysiology encompasses a complex group of diseases. The presence of systemic and pulmonary outflow tract

Current surgical management of single ventricle is divided into 3 stages. Stage I operation technique is dependent on patients' status. Surgical palliation is to achieve following goals: unobstructive systemic blood flow, balanced and limited pulmonary blood flow, minimal AV valve regurgitation, nondistorted pulmonary arteries, and unrestricted return of blood to the ventricle. If pulmonary flow is unrestricted, pulmonary banding is done to minimize ventricular overload and avoid pulmonary hypertension. If systemic obstruction is noted, Norwood operation or Damus-Kaye-Stansel palliation is used. A systemic to pulmonary shunt, such as Blalock-Taussig (B-T) shunt is placed to provide pulmonary blood flow in patients with obstructed pulmonary circulation. In addition, AV valve repair and atrial septostomy may be needed according to patients' condition. The preoperative TEE exam includes the evaluation of AV and VA connections, AV valve morphology and function, degree of outflow tract obstruction, size and morphology of ventricles, and associated cardiac anomalies. The postoperative TEE exam should focus on the presence of systemic outflow tract obstruction, AV valve function, status of pulmonary blood flow and ventricular function.

Stage II operation mainly aims to connect SVC to PA and eliminate or restrict other sources for pulmonary blood flow. Bidirectional Glenn shunt and hemi-Fontan anastomosis are representatives. Bidirectional Glenn shunt is built from SVC to PA. After the operation, the

strategy must be undertaken.

Congenital heart disease is a complex disease entity of various severities. Intraoperative TEE offers valuable information about patients' anatomy and pathophysiology. In addition to diagnosis confirmation, TEE is a useful guide for surgical planning and anesthetic management. Intraoperative assessment by TEE images may be difficult due to complicated pathological presentations. A thorough understanding of anatomy, pathophysiology, and surgical procedure of congenital heart disease is required for interpretation of intraoperative TEE.

**Part 3** 

**Echocardiography in Special Disease** 

#### **5. References**

