The positional relationship between the coronary sinus musculature and the atrioventricular septal junction.
OBJECTIVE
The atrioventricular (AV) septal junction includes the coronary sinus (CS) and the compact part of the AV node and its posterior extensions. It has been recognized as the target site for ablation therapy of the AV nodal reentrant tachycardia and its variant forms. Despite the clinical significance of this region, the arrangement of the musculature in the AV septal junction, including the CS, has not fully been elucidated. We tried to explore the histological muscular diversity within the AV septal junction.


RESULTS
Sixteen autopsied human hearts (seven women), mean age 59.8 years, without structural anomalies, were studied. We removed the whole AV septum, including the CS opening after the macroscopic measurements, and prepared serial sections parallel to mitral and tricuspid annuli (short-axis style) to elucidate the positional relationships between the compact AV node and the CS musculature. Out of 16 hearts, the CS musculature extended deeply into the AV septal junction in eight hearts. In the other eight hearts, the CS musculature was located above the AV septal junction. In the former group, we found that the offset of both annuli was wide (mean 3.8 +/- 1.4 vs. 2.4 +/- 1.1 mm), the distance between CS opening and membranous septum was long (mean 14.8 +/- 1.6 vs. 12.3 +/- 2.2 mm), and the CS opening level was lower and closer to the His bundle level (mean 2.8 +/- 1.9 vs. 5.8 +/- 2.9 mm) (P < 0.05).


CONCLUSIONS
The deep extension of CS musculature into the AV septal junction seems to increase the tissue non-uniformity in this area.
Department of Pathology, National Cardiovascular Center, 5-7-1 Fujishirodai Suita-City, 565-8565 Osaka, Japan. takamatu@hsp.ncvc.go.jp
Taka-aki
TA
Matsuyama
Hatsue
H
Ishibashi-Ueda
Yoshihiko
Y
Ikeda
Yuko
Y
Yamada
Hideo
H
Okamura
Takashi
T
Noda
Kazuhiro
K
Satomi
Kazuhiro
K
Suyama
Wataru
W
Shimizu
Naohiko
N
Aihara
Shiro
S
Kamakura
Shin
S
Inoue
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054087:Atrial Septum / Q000033:anatomy & histology*; D001283:Atrioventricular Node / Q000033:anatomy & histology; D001344:Autopsy; D054326:Coronary Sinus / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D054088:Ventricular Septum / Q000033:anatomy & histology*