title: Study of the traction resistance of mitral valve chordae tendineae.
abstract: OBJECTIVE
  To determinate the extension and the resistance of the primary mitral valve chordae tendineae when submitted to traction. The importance of keeping the integrity of papillary muscle, chordae tendineae, and mitral valve cuspid when the replacement of this valve occurs is clear, but the knowledge of the maximum resistance that a primary tendinea chorda can withstand is not known.
  
  
  METHODS
  Eight hearts were dissected, and one hundred and thirty two primary human chordae tendineae were measured (length and thickness) and submitted to traction under controlled conditions so that the absolute resistance, resistance relative to thickness (relative resistance), and elongation could be measured.
  
  
  RESULTS
  The correlation between the elongation at the moment of rupture and the thickness was equal to 1.54 + 17.02 x thickness (P = 0.026); and to absolute resistance was equal to 0.95 + 1.42 x resistance (P < 0.001); and to the resistance relative to thickness (relative resistance) was equal to 1.95 + 0.08 x relative resistance (P = 0.009). The correlation between the absolute resistance and the thickness was equal to 0.26 + 14.53 x thickness (P < 0.001).
  
  
  CONCLUSIONS
  The resistance of primary mitral valve chordae tendineae is associated with its thickness and elongation at the moment of rupture, but is not associated with the length. The elongation at the moment of rupture shows a relationship with the resistance relative to thickness (relative resistance) and with the thickness of the primary chordae tendineae, but not with the length of the chordae tendineae.
authors.affiliation: Heart Institute, Hospital das Clínicas, São Paulo University Medical School, São Paulo, SP, Brazil. frede_lobo@yahoo.com.br
authors.forename: Frederico Lafraia
authors.initials: FL
authors.lastname: Lobo
authors.forename: Flávio Roberto
authors.initials: FR
authors.lastname: Takeda
authors.forename: Carlos Manuel de Almeida
authors.initials: CM
authors.lastname: Brandão
authors.forename: Domingo Marcolino
authors.initials: DM
authors.lastname: Braile
authors.forename: Fabio Biscegli
authors.initials: FB
authors.lastname: Jatene
authors.forename: Pablo Maria Alberto
authors.initials: PM
authors.lastname: Pomerantzeff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002815:Chordae Tendineae / Q000502:physiology*; D004548:Elasticity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D010210:Papillary Muscles / Q000502:physiology; D012421:Rupture; D013314:Stress, Mechanical