Text Box: ANATOMIC PATTERNS OF LEFT VENTRICULAR OUTFLOW TRACT OBSTRCTION IN ATRIOVENTRICULAR SEPTAL DEFECT
Huang MR, Paul M Weinberg, Shang-Liang Chen
The Shanghai Children' s Medical Center, Shanghai, China
The Children 's Hospital of Philadelphia, Philadelphia, USA
 
Objective: The long and narrow left ventricular outflow tract (LVOT) is a known anatomic feature of atrioventricular septal defect (AVSD). It can easily lead to LVOTO in some cases. The delineation of anatomic pattern in AVSD complicated with LVOTO is important for successful surgical management. We sought to determine the anatomic patterns of LVOTO and their relative frequency.
Methods: We analyzed 88 posmorterm heart specimens with AVSD, which had not been operated, on 62with complete AVSD, 26 with incomplete AVSD.
Results: LVOTO was present in 26/88 (30%): 16/62(26%) with complete AVSD and 10/26(38%) with incomplete AVSD. There were 4 anatomic patterms of LVOTO:  Adhesion of common AV valve leaflet to the septum in 13(50%); abnormal chordal attachment to septum in 10(38%); extension of anteriolateral papillary muscle into LVOT in 2(8%); and malalignment of the posterior portion of the infundibular septum towards the left in 1(3%).
Conclusion:  AVSD has a high tendency to result in complicate the LVOTO, especially in cases with incomplete AVSD; abnormal attachment of common valve leaflet and chordal attachment to the septum were two main patterns.
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