| Abstrakt: |
Electrophysiological delineation of the specialized conduction system was performed under cardiotomy on 64 patients: 51 with ventricular septal defect (VSD), 11 with tetralogy of Fallot (TOF) and 2 with transposition of the great arteries (TGA, III). Some histological study was done for confirmation. In large VSD of type II or III, superficial location of the His bundle was shown by a tall H deflection recorded along the inferior rim, coinciding with a high incidence of conduction disturbance in this malformation. One characteristic in TOF was a deflection recorded along the posteroinferior rim rather exclusively on the left ventricular side, coinciding with the anatomic course of the His bundle. A deflection was frequently recorded at an area a few mm posterior to the muscle of Lancisi (ML) or the Lancisi equivalent structure (LES); it was relatively common in ordinary types of VSD, and presumed as the penetrating site of the right bundle branch (RBB) and/or near the bifurcated portion of the His bundle. The second portion of the RBB was not clearly delineated in general, particularly in TOF, but always found within the septomarginal trabecle when delineated. Our conclusion, together with histological study, was that one may use the ML or the LES as a rough marking for the course of the RBB. By this recognition, the surgically induced complete right bundle branch block has been diminished significantly. Variation of the course of conduction system as well as limits of this diagnostic measure are described herein. |
