Microanatomy of Left Bundle Branch in Chinese Adult Hearts: Aiming to the Research on Morphological Information.

Background: The left bundle branch (LBB) in human heart is very thin and certainly individually different, so the corresponding anatomical data is relatively rare. The gradual spread of His-Purkinje system pacing and aortic valve replacement is in great need of support from the morphological data of LBB. Our pre-investigation suggested that the morph of LBB may be ethnically different. Therefore, we herein focus on exploring and summarizing the morphological characteristics of LBB in the Chinese adult hearts. Methods : The LBB of 35 Chinese adult hearts were microanatomized by the system of stereomicroscope & camera, and then the anatomical elements of the LBB were examined, measured and statistically analyzed under this system. Results : The widths of proximal portion of the LBB were approximately 1 cm ( x ¯ ± S, 0.92 ± 0.22 cm), and the shapes of it were flat and broad. This characteristic of shape bears traces of natural selection. On the other hand, in the view from the left ventricular septum, the minimum distances between the anterior boundary of LBB and the right coronary aortic valve ring (RCAR) were only about 1 mm ( x ¯ ± S, 1.02 ± 0.58 mm), and the posterior boundary almost coincided with the posterior angle of the membranous septum (Near the central fibrous body). By comparison, some anatomical elements of LBB in the Chinese adult heart should be different from those in other ethnic heart. Conclusion : The RCAR and the posterior angle of the membranous septum can be used to estimate the range of the proximal portion of LBB in Chinese hearts.