DK2985_C000 1..28 - AlSharqia Echo Club

550 Transesophageal Echocardiography(A) (B) (C)Figure 24.32 D-Transposition of the great arteries (TGA). (A) The aorta is connected to the right ventricle while the pulmonary arteryis connected to the left ventricle. Therefore, systemic venous blood returns to the right atrium, from which it goes to the right ventricle andthen back to the systemic circulation through the aorta. Pulmonary venous blood returns to the left atrium, from which it goes to the leftventricle and then to the pulmonary artery. Survival is possible only if there is a communication between the two parallel circuits, such aswith a patent ductus arteriosus. (B) The “atrial switch” operation: a baffle is created in the atria, so that blood returning from the systemicvenous circulation is diverted into the left ventricle and then the pulmonary artery (blue arrows), whereas blood returning from the pulmonaryvenous circulation is directed into the right ventricle and then the aorta (red arrow). (C) The “arterial switch” operation: the pulmonaryartery and ascending aorta are transected above the semilunar valves and coronary arteries, are then switched (neoaortic andneopulmonary valves). [With permission from Brickner et al. (18).]sequelae in patients who underwent an atrial switch operationinclude: right (systemic) ventricular dysfunction, significantTR, symptomatic bradycardia, tachycardia, or sicksinus syndrome. Other potential late complications includeobstruction of the SVC or IVC venous pathways, baffleleak resulting in significant left-to-right or right-to-leftshunting, progressive left ventricular outflow subpulmonaryobstruction (19,20). Some of those sequelae are bestapproached by percutaneous interventions: balloon angioplastyand stent insertion for baffle obstruction or occlusiondevices for baffle leaks. Other sequelae such asatrioventricular valve regurgitation, subpulmonary,obstruction, or ventricular dysfunction require surgery.The patient with a failing RV and severe TV regurgitationmay be considered for heart transplantation.Late complications of the arterial switch procedureinclude significant RVOT obstruction, myocardial ischemiafrom coronary artery obstruction, and neoaorticvalve regurgitation (21). Those complications need to beapproached surgically. Rastelli patients may developright ventricular to pulmonary artery conduit obstruction,subaortic obstruction across the left ventricular-aortatunnel, VSD and pulmonary branch stenosis.TEE in Operated Transposition of the GreatArteries (Table 24.2)The TEE examination of operated TGA should includeevaluation of ventricular function, atrioventricular valvecompetence, obstruction of the pulmonary or the systemicvenous pathways (baffle), and baffle leakage. Theseanomalies can be seen using a combination of the midesophagealfour-chamber and bicaval views. Transesophagealechocardiography can also be used to guidecatheter closure of baffle leaks or as a pre- and postoperativetool to assist the surgeon in the repair.C. Complex Single VentriclePatients with a single ventricle have either a single anatomicalventricle made up of a single pouch of undeterminateorigin or, more commonly, a functionally singleventricle with one well-formed ventricle accompanied bya second underdeveloped or rudimentary ventricle(Fig. 24.33). The atria can be solitus, inversus or ambiguous.The atrioventricular connection consists of a commonvalve or two separate valves, one patent and the otheratretic. The well-developed ventricular chamber can beof the left or right ventricular type. The ventriculoarterialconnection can be concordant or discordant, or the greatarteries can arise from the same ventricle and be eitherpatent or stenotic. The most common types of singleventricle of left ventricular morphology consist of tricuspidatresia, pulmonary atresia with intact ventricularseptum and double inlet LV (Fig. 24.33). The mostcommon single RV is the hypoplastic left heart syndrome(Fig. 24.34).Physiologically, the patient with a single ventricle maydisplay restricted pulmonary blood flow with cyanosis orobstructed systemic arterial flow with heart failure and