The Limbic Ledge A Landmark for Transseptal Left Heart

SINCE its initial description, ' transseptal left heart catheterization has been in-creasingly used as a diagnostic and a re-search technic. While refinements in instrumentation have emerged 2, 3 the method of septal puncture has remained unchanged. The original de-scription of septal puncture required that the catheter and needle assembly be positioned in the right atrium at a point near the junc-tion of the lower and middle thirds of the atrium against the septal wall. With the tip pointing posteriorly and to the left, the needle was unsheathed and passed through the septum into the left atrium. The uncer-tainty and anxiety in locating the best punc-ture site are implied by Cope 4 and Al-dridge5 who have used the aortic valve, visual-ized by a retrograde aortic catheterization as an indirect aid to septal puncture site, but to our knowledge no direct, right atrial land-mark has been utilized for this objective. In addition no modification of the puncture site has been. suggested to accommodate the ana-tomic variations found in abnormal hearts. This paper describes an aid to transseptal catheterization based on the identification of the limbus fossa ovalis, the ledge overhanging the fossa. The application of this modified technic and its increased safety are presented in a series of 145 patients. Method After standard percutaneous right femoral vein insertion, the sheathed Brockenbrough needle is advanced with the tip directed to the patient'