Concept
The Senning procedure is an atrial switch heart operation performed to treat transposition of the great arteries. It is named after its inventor, the Swedish cardiac surgeon Åke Senning (1915–2000), also known for implanting the first permanent cardiac pacemaker in 1958. This procedure, a form of atrial switch, was developed and first performed by Senning in 1957 as a treatment for d-TGA (dextro-Transposition of the great arteries) before improvements in cardiopulmonary bypass made more curative surgical techniques feasible. In this congenital heart defect, the venous circulation drains into the right ventricle but from this chamber, blood is directed towards the systemic circulation through the aorta. This is also expressed by the term ventriculoarterial discordance, that is the ventricles are connected to the wrong great artery (the right ventricle to the aorta, thus pumping blood from the systemic venous back into the systemic arterial circulation). Thus, d-TGA is not to be confused with l-TGA, where there is both atrioventricular and ventriculoarterial discordance. In absence of a shunt, patients with d-TGA could not survive, because there would be no flow of oxygenated blood (coming from the pulmonary veins) to the rest of the body after the normal prenatal shunts physiologically close a few weeks after birth. This congenital heart defect caused babies to "turn blue" due to the lack of oxygen flowing through the blood. Before this technique became available, in 1950, two cardiac surgeons, Blalock and Hanlon, had developed a palliative procedure which consisted in opening the atrial septum. Being that in TGA the atrial septum prevents oxygenated blood from reaching the systemic circulation, this simpler procedure leads to improvements in systemic arterial O2 saturation. With the Senning surgical repair, a baffle – or conduit - is created within the atria that reroutes the deoxygenated blood coming from the inferior and superior venae cavae to the mitral valve and therefore to the pulmonary circulation This is accomplished by creating a systemic venous conduit that channels deoxygenated blood from the superior and inferior vena cava towards the mitral valve.