The significance of aortic overriding and pulmonary stenosis in tetralogy of Fallot

Abstract

We are indebted to Dr Yurekli and his colleagues for their kind comments 1 regarding our review 2 of the problems produced by hearts with overriding aortic valves. We agree totally with the sentiments that they have expressed. We endorse in particular their comment that techniques such as MRI or CT angiography are now able to demonstrate the anatomy as well, or even better, than the morphologist who holds the heart itself in his or her hands. We hope that this fact was well demonstrated in our review itself. We also support the suggestions made by Dr Yurekli and his colleagues regarding the potential pitfalls awaiting those who might be tempted to achieve transcatheter closure in the setting of overriding arterial valves. The very presence of the malalignment between the muscular ventricular septal components, which underscores the overriding, points to the difficulties of achieving complete closure when inserting a planar device within the curved surface that we believe should be considered as representing the "ventricular septal defect". This potential problem is perhaps even greater than the chance of the device impinging on the leaflets of the aortic valve, and is present when the malaligned outlet septum is muscular rather than fibrous.