sail sound		An auscultatory finding in some patients with Ebstein anomaly. The S1 includes mitral valve closure as its first component with a delayed tricuspid component. The abnormally large tricuspid anterior leaflet snapping like a sail catching the wind causes this delayed closure. The sail sound is not an ejection click, although it may simulate one.
scimitar syndrome		A constellation of anomalies including infradiaphragmatic total or partial anomalous pulmonary venous connection of the right lung to the inferior vena cava, often associated with hypoplasia of the right lung and right pulmonary artery. The lower portion of the right lung tends to receive its arterial supply from the abdominal aorta. The name of the syndrome derives from the appearance on PA chest x-ray of the shadow formed by the anomalous pulmonary venous connection, which resembles a Turkish sword, or scimitar.
secondary erythrocytosis		erythrocytosis. see also polycythemia vera.
Senning procedure (operation)		An operation for complete transposition of the great arteries in which venous return is directed to the contralateral ventricle by means of an atrial baffle fashioned in situ by using right atrial wall and interatrial septum. As a consequence, the right ventricle supports the systemic circulation. A type of “atrial switch” operation. see also Mustard procedure. see also atrial switch operation. see also double switch operation. (Senning A. Surgical correction of transposition of the great vessels. Surgery 1959;45:966-980.)
Shone complex (syndrome)		An association of multiple levels of left ventricular inflow and outflow obstruction (subvalvar and valvar LVOTO, coarctation of the aorta and mitral stenosis [parachute mitral valve and supramitral ring]). (Shone JD et al: The developmental complex of "parachute mitral valve”, supravalvular ring of left atrium, subaortic stenosis and coarctation of aorta. Am J Cardiol 1963;11:714-725.)
Shprintzen syndrome		see velo-cardio-facial syndrome. see CATCH 22.
shunt		Movement of blood through a congenitally abnormal or surgically created connection and communication between two circuits, at the level of the atria, ventricles, or great vessels. “Shunt” is a physiologic term, in contrast to “connection” which is an anatomic term.
single (as in atrium, ventricle, etc.)		Implies absence of the corresponding contralateral structure. Contrasts with “common”, which implies bilateral structures with absent septation. see also common.
sinus venosus		An embryologic structure, precursor of the inferior vena cava, superior vena cava and coronary sinus and part of the definitive right atrium,located external to the primitive right atrium in the early embryologic period (3 to 4 week gestation). The sinus portion of the right atrium receives the inferior vena cava, superior vena cava and coronary sinus. The right and left valves of the sinus venosus separate the sinus venosus from the primitive right atrium, the embryologic precursor of the trabeculated or muscular portion of the right atrium and the right atrial appendage, which in turn communicates with the tricuspid valve. The left valve of the sinus venosus joins the interatrial septum, retrogresses and is absorbed. The right valve of the sinus venosus enlarges and functions to deflect oxygenated fetal blood coming from the placenta via the inferior vena cava across the foramen ovale. see also cor triatriatum dexter, sinus venosus defect.
sinus venosus ASD		see ASD.
sinus venosus defect		A communication located postero-superior (or rarely postero-inferior) to the oval fossa, commonly associated with partial anomalous pulmonary venous connection (most often right pulmonary veins, especially the right upper pulmonary vein in association with a postero-superior defect), which is functionally identical to an atrial septal defect, but properly named a sinus venosus defect because it occurs due to abnormal development of the sinus venosus in relation to the pulmonary veins and is not a defect in the interatrial septum. The caval vein overrides the rim of the fossa ovalis leading to a biatrial communication, a characteristic anatomical feature. see also atrial septal defect
situs		syn. sidedness. The position of the morphologic right atrium determines the sidedness and is independent of the direction of the cardiac apex, or the positions of the ventricles or the great arteries.
situs ambiguus		Indeterminate sidedness (in the setting of atrial isomerism).
situs inversus		Mirror-image sidedness, i.e. opposite of normal. Left-sided morphologic right atrium.
situs inversus totalis		Total mirror-image sidedness. The position of all lateralized organs is inverted.
situs solitus		Normal sidedness. Right-sided morphologic right atrium.
Spinnaker formation		Undue and aneurysmal prominence of the persistent right valve of the sinus venosus which may traverse the tricuspid valve and protrude into the right ventricle and/or right ventricular outflow tract, leading to right ventricular outflow tract obstruction. syn. windsock formation. see Thebesian valve, Eustachian valve, Chiari network
stent		Intravascular (intraluminal) prosthesis to scaffold a vessel following transluminal balloon dilatation, for the purpose of maintaining patency.
Sterling Edwards procedure		A palliative operation for transposition of the great arteries in which the atrial septum was resected, repositioned, and sutured to the left of the right pulmonary veins to produce drainage into the right atrium. The procedure produced left to right shunt of oxygenated blood directly into the systemic atrium and ventricle and offloaded the pulmonary circulation in patients with complete transposition of the great arteries and high pulmonary flow. (Edwards WS, Bargeron LM et al. Reposition of right pulmonary veins in transposition of the great vessels. JAMA 1964;188:522-523. Edwards WS, Bargeron LM. More effective palliation of the transposition of the great vessels. J Thorac Cardiovasc Surg 1965;19:790-795.)
straddling A-V valve		see atrio-ventricular valve.
subpulmonary ventricle		The ventricle that relates most directly to the pulmonary artery.
supero-inferior heart		A term applied to a heart the ventricles of which are in a markedly supero-inferior relationship due to abnormal displacement of the ventricular mass along the horizontal plane of its long axis. Often coexists with criss-cross atrio-ventricular relationships. see also criss-cross heart. syn. over-and-under ventricles; upstairs-downstairs heart.
supracristal		Located above the crista ventricularis in the RV outflow tract, hence contiguous with the origin of the great arteries. see crista ventricularis.
supraregional referral centre (SRRC)		A “full service” centre for providing optimal care of adult patients with CHD comprising specialized resources, the availability of cardiology specialists with specific training and experience in ACHD, the availability of other cardiology sub-specialists and other medical and paramedical personnel with special training/experience in the problems of congenital heart disease, and offering opportunities for training, research and education in the field. syn. national referral centre.
supravalvar mitral ring		An anomaly found in the left atrium that produces congenital mitral stenosis. see also cor triatriatum. see also Shone complex.
switch-conversion of transposition		An operation performed in patients with congenitally corrected transposition of the great arteries, or in patients who had previously had a Mustard or Senning procedure for complete transposition of the great arteries, to allow the left ventricle to assume the function of the systemic ventricle. The first stage may involve pulmonary artery banding to induce pulmonary left ventricular hypertrophy. The second stage involves an arterial switch operation in both groups and a Mustard or Senning operation in patients with congenitally corrected transposition, or removal of the Mustard/Senning atrial baffles and reconstruction of an atrial septum in patients with complete TGA. see also double switch operation.
systemic A-V valve		The atrio-ventricular valve guarding the inlet to the systemic ventricle.
systemic A-V valve		The atrio-ventricular valve guarding the inlet to the systemic ventricle.