Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ Key Features +++ Essentials of Diagnosis ++ Early heart failure (HF) with or without cyanosis Systolic ejection click +++ General Considerations ++ Accounts for < 1% of congenital heart malformations A single great artery arises from the heart, giving rise to the systemic, pulmonary, and coronary circulations The number of truncal valve leaflets varies from two to six, and the valve may be insufficient or stenotic Divided into subtypes by the anatomy of the pulmonary circulation A single main pulmonary artery may arise from the base of the trunk and gives rise to branch pulmonary arteries (type 1) Alternatively, the pulmonary arteries may arise separately from the common trunk, either in close association with one another (type 2) or widely separated (type 3) The degree of systemic arterial oxygen saturation depends on the ratio of pulmonary to systemic blood flow If pulmonary vascular resistance is normal, the pulmonary blood flow is greater than the systemic blood flow and the saturation is relatively high If pulmonary vascular resistance is elevated because of pulmonary vascular obstructive disease or small pulmonary arteries, pulmonary blood flow is reduced and oxygen saturation is low +++ Clinical Findings ++ Growth retardation, easy fatigability, and HF are most common manifestations High pulmonary blood flow is characteristic Cyanosis Usually minimal More profound in patients with decreased pulmonary blood flow Examination of the heart reveals a hyperactive precordium At the lower left sternal border A systolic murmur is heard A systolic thrill is common A loud holosystolic murmur is audible A loud early systolic ejection click is commonly heard A diastolic flow murmur can often be heard at the apex due to increased pulmonary venous return crossing the mitral valve An additional diastolic murmur of truncal insufficiency may be present S1 and S2 are single and loud A VSD is always present +++ Diagnosis +++ Imaging ++ Radiography Shows cardiomegaly; absence of the main pulmonary artery segment; and a large aorta, which has a right arch 30% of the time Pulmonary vascular markings vary with the degree of pulmonary blood flow Echocardiography Shows override of a single great artery (similar to tetralogy of Fallot, but no second great artery arises directly from the heart) Defines origin of the pulmonary arteries and the degree of truncal valve abnormality Color-flow Doppler can aid in the description of pulmonary flow and the function of the truncal valve, both of which are critical to management Identifies associated lesions that will impact surgical planning, such as the presence of an interrupted aortic arch +++ Diagnostic Procedures ++ Electrocardiography The axis is usually normal Right ventricular hypertrophy or combined ventricular hypertrophy is commonly present Cardiac catheterization Not routinely performed May be of value in older infants in whom pulmonary vascular disease must be ruled ... Your MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth