title: Quantitative Evaluation of the Substantially Variable Morphology and Function of the Left Atrial Appendage and Its Relation with Adjacent Structures.
abstract: OBJECTIVE
  To investigate quantitatively the morphology, anatomy and function of the left atrial appendage (LAA) and its relation with adjacent structures.
  
  
  METHODS
  A total of 860 patients (533 men, 62.0%, age 55.9±10.4 year) who had cardiac multidetector computed tomography angiography from May to October 2012 were enrolled for analysis.
  
  
  RESULTS
  Seven types and 6 subtypes of LAA morphology were found with Type 2 being the most prevalent. Type 5 was more significantly (P<0.05) present in women (8.0%) than in men (4.2%). LAA orifice was oval in 81.5%, triangular in 7.3%, semicircular in 4%, water drop-like in 3.2%, round in 2.4% and foot-like in 1.6%. The LAA orifice had a significantly greater (P<0.01) major axis in men (24.79±3.81) than in women (22.68±4.07). The LAA orifice long axis was significantly (P<0.05) positively correlated with the height, weight and surface area of the patient. The LAA morphology parameters displayed strong positive correlation with the left atrium volume, aortic cross area long axis or LSPV long axis but poor correlation with the height, weight, surface area and vertebral body height of the patients. Four types of LAA ridge were identified: AI, AII, B and C with the distribution of 17.6%, 69.9%, 5.9% and 6.6%, respectively. The LAA had a significantly (P<0.05) greater distance from its orifice to the mitral ring in women than in men. The LAA had two filling and two emptying processes with the greatest volume at 45% phase but the least volume at 5% phase. The LAA maximal, minimal and emptying volumes were all significantly (P<0.05) positively correlated with the body height, weight and surface area, whereas the LAA ejection fraction had an inverse correlation with the LAA minimal volume but no correlation with the maximal volume.
  
  
  CONCLUSIONS
  The LAA has substantially variable morphologies and relation with the adjacent structures, which may be helpful in guiding the LAA trans-catheter occlusion or catheter ablation procedures.
authors.affiliation: Department of Medical Imaging, Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Cai-Ying
authors.initials: CY
authors.lastname: Li
authors.affiliation: Department of Medical Research, Shijiazhuang First Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Bu-Lang
authors.initials: BL
authors.lastname: Gao
authors.affiliation: Department of Medical Imaging, Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Liu
authors.affiliation: Department of Medical Research, Shijiazhuang First Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Qiong-Ying
authors.initials: QY
authors.lastname: Fan
authors.affiliation: Department of Medical Research, Shijiazhuang First Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Xue-Jing
authors.initials: XJ
authors.lastname: Zhang
authors.affiliation: Department of Medical Research, Shijiazhuang First Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Guo-Chao
authors.initials: GC
authors.lastname: Liu
authors.affiliation: Department of Medical Imaging, Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Hai-Qing
authors.initials: HQ
authors.lastname: Yang
authors.affiliation: Department of Medical Imaging, Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Ping-Yong
authors.initials: PY
authors.lastname: Feng
authors.affiliation: Department of Medical Imaging, Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Medical Imaging, Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Song
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult