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Updated: Aug 20, 2026

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
Published on: September 17, 2015
A new classification of the mitral papillary muscle
Denis Berdajs1, Patonay Lajos, Marko I Turina
1University Hospital Zürich, Department of Cardiovascular Surgery, Switzerland. denis_berdajs@hotmail.com
Background:
Mitral valve homograft implantation and reconstruction of the left ventricular subvalvular apparatus requires a good knowledge of the morphology of the left papillary muscles. A comprehensive description of the left ventricular subvalvular apparatus is presented to aid in this procedure and to support conventional and endoscope-assisted reconstruction of the chordae tendineae.
Material/Methods:
The subvalvular apparatuses of 100 unfixed human hearts were investigated. Papillary muscles were endoscopically examined on the hearts in situ, then the hearts were explanted and the subvalvular apparatus was macroscopically inspected. The geometrical arrangement of the chordae tendineae was determined.
Results:
We defined three groups of the left ventricular papillary muscle. In group I the basal part and the apex of the muscle were undivided. In group II there were two heads; in subgroup II/A the base of the papillary muscle was undivided and in II/B it was divided into two separate parts. In group III the papillary muscle had three heads. In subgroup III/A the base was undivided, while in III/B it was made up of two and in III/C three separate parts.
Conclusions:
We propose a classification of the left ventricular subvalvular apparatus based on the macroscopic and endoscopic investigations. It emphasizes the morphology of the apical and basal parts of papillary muscles and includes the geometrical arrangement of the chordae tendineae. Thus it may be of a great value in endoscopic and conventional mitral valve replacement or reconstruction of the chordae tendineae and in mitral valve homograft implantation.
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