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. Author manuscript; available in PMC: 2010 Feb 1.
Published in final edited form as: Nat Genet. 2009 Jul 13;41(8):931–935. doi: 10.1038/ng.415

Figure 1.

Figure 1

Anatomy and pathophysiology of tetralogy of Fallot (TOF). Normal heart structure (a) promotes unidirectional flow of deoxygenated blood (blue) into the lungs and oxygenated blood (red) into the aorta. In TOF (b) pulmonary stenosis and narrowing of the right ventricular outflow tract (RVOT) impedes the flow of deoxygenated blood into the lungs, and both the ventricular septal defect (VSD) and overriding aorta (*) promote the flow of deoxygenated blood into the systemic circulation, to produce cyanosis (sometimes referred to as “blue baby” syndrome). Right ventricular hypertrophy (RVH) is also present. (c) A Doppler echocardiogram shows mixing of deoxygenated blood from the right ventricle (RV) and oxygenated blood from the left ventricle (LV) as blood is pumped out the overriding aorta (Ao) in a patient with TOF. RA, right atrium; LA, left atrium. Images from Multimedia Library of Congenital Heart Disease, Children’s Hospital, Boston, MA, editor Robert Geggel, MD, www.childrenshospital.org/mml/cvp, with permission.