title: Isolated right atrial appendage (RAA) rupture in blunt trauma--a case report and an anatomic study comparing RAA and right atrium (RA) wall thickness.
abstract: BACKGROUND
  Heart chambers rupture in blunt trauma is uncommon and is associated with a high mortality. The determinant factors, and the incidence of isolated heart chambers rupture remains undetermined. Isolated rupture of the right atrium appendage (RAA) is very rare, with 8 cases reported in the reviewed literature. The thin wall of the RAA has been presumed to render this chamber more prone to rupture in blunt trauma.
  
  
  OBJECTIVE
  To report a case of isolated RAA rupture in blunt trauma, and to compare right atrium (RA) and RAA wall thickness in a necropsy study.
  
  
  METHODS
  The thickness of RA and RAA wall of hearts from cadavers of fatal penetrating head trauma victims was measured. Our case of isolated RAA rupture is presented. The main findings of the 8 cases reported in the literature, and the findings of our case, were organized in a table.
  
  
  RESULTS
  The comparison of the data showed that wall thickness of the RAA (0.53 +/- 0.33 mm) was significantly thinner than that of RA (1.11 +/- 0.42 mm) (p < 0.05).
  
  
  CONCLUSIONS
  In all these 9 cases of isolated RAA rupture, cardiac tamponade occurred, RAA rupture was diagnosed intraoperatively and sutured, and the patients survived. Main mechanisms hypothesized for heart chamber rupture include mechanical compression coincident with phases of cardiac cycle, leading to high hydrostatic pressure inside the chamber. Published series include numerous cases of RA rupture, and only a few cases of RAA rupture.
  
  
  CONCLUSIONS
  Thus, our data suggests that wall thickness is not a determinant factor for RA or RAA rupture in blunt trauma.
authors.affiliation: Emergency Surgery Service, Clinics Hospital, University of São Paulo Medical School, Rua Dr, Eneas de C Aguiar, 255 CEP 05403-000, São Paulo, SP, Brazil. adofmusp@hotmail.com
authors.forename: Adoniram M
authors.initials: AM
authors.lastname: Figueiredo
authors.forename: Renato S
authors.initials: RS
authors.lastname: Poggetti
authors.forename: Fabio G
authors.initials: FG
authors.lastname: Quintavalle
authors.forename: Belchor
authors.initials: B
authors.lastname: Fontes
authors.forename: Moise
authors.initials: M
authors.lastname: Dalva
authors.forename: Riad N
authors.initials: RN
authors.lastname: Younes
authors.forename: Fabio B
authors.initials: FB
authors.lastname: Jatene
authors.forename: Dario
authors.initials: D
authors.lastname: Birolini