title: Atrial septal pouch - Morphological features and clinical considerations.
abstract: BACKGROUND
  The atrial septal pouch (SP) is a new anatomical entity within the interatrial septum. The left-sided SP may be the source of thrombus and contribute to ischemic stroke. The aim of this study was to provide a detailed morphometric description of the SP.
  
  
  METHODS
  Two hundred autopsied hearts (23% deriving from females) with a mean age of 46.7±19.1years were investigated. We assessed the morphology of the interatrial septum. We obtained measurements and casts of the SPs, and we conducted histological staining of the left-sided SPs.
  
  
  RESULTS
  Patent foramen ovale was observed in 25% of hearts. We found a left SP in 41.5%, right in 5.5% and a double SP in 5.5% of hearts. We found the patent foramen ovale (PFO) more often in younger hearts, and the SP and smooth septum were more prevalently found in older hearts (p=.0023). The mean volume of the left-sided SP was 0.31±0.11ml, which represented 13.6±9.4% (range: 3.1-44.9%) of the left atrial appendage volume. The SP shape resembled a cone or a cylinder with some smaller diverticula originating from the main body. The SP free wall was composed of two layers of endocardium, transverse muscle fibers and connective tissue.
  
  
  CONCLUSIONS
  A left-sided SP was present in 47% of individuals. The SP arises as a result of PFO channel closure. The anatomy of left-sided SP may promote blood stasis and thrombus formation. The universal formula for SP volume was calculated.
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland. Electronic address: mkh@onet.eu.
authors.forename: Mateusz K
authors.initials: MK
authors.lastname: Hołda
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Koziej
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Jakub
authors.initials: J
authors.lastname: Hołda
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piątek
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Kamil
authors.initials: K
authors.lastname: Tyrak
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Weronika
authors.initials: W
authors.lastname: Chołopiak
authors.affiliation: Department of Forensic Medicine, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Filip
authors.initials: F
authors.lastname: Bolechała
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Jerzy A
authors.initials: JA
authors.lastname: Walocha
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Wiesława
authors.initials: W
authors.lastname: Klimek-Piotrowska
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054087:Atrial Septum / Q000033:anatomy & histology* / Q000166:cytology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D054092:Foramen Ovale, Patent / Q000473:pathology*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D011897:Random Allocation; D055815:Young Adult
keywords: Interatrial septum; Left atrial appendage; Left atrium; Patent foramen ovale; Stroke