Praveen Mulki Shenoy1, Amith Ramos2, Narasimha Pai 3, Bharath Shetty4, Aravind Pallipady Rao5
BACKGROUND
The papillary muscle basal connections have significant clinical implications.
Variety of studies done on its morphology and function by various specialists in
different departments. A close look on these revealed the interconnections of
papillary muscles to one another and to the interventricular septum of both
ventricles is related to uncoordinated contractions of papillary muscles, leading to
hyper or hypokinesia or prolapse or even its rupture.
METHODS
Our study done in 25 formalin soaked hearts revealed after the deep and
meticulous dissection, reflecting the walls of ventricles laterally the numerous
interconnections of papillary muscles at its bases and IVS. Ventricles are opened
by inverted ‘L’ shaped incision and its reflected more laterally till all the papillary
muscles is visible in one frame after incising the moderator band. The connections
were noted, measured, photographed, tabulated, compared with similar studies
and analysed with experts with respective fields.
RESULTS
Almost all the specimens did have the interconnections. Further the post mortem
findings of the cardiac related deaths with involvement of papillary muscles
suggest damage to such ‘bridges’. The moderator band extensions to the base of
right APM, and its extension to the posterior groups is noted in all the specimens.
The bridge from the IVS to bases of both the groups of papillary muscles is noted
in left ventricle. In90% of specimens the one PPM is found to be loosely connected,
more so in left ventricle.
CONCLUSIONS
We are of a conclusion that such basal interconnections and to the interventricular
septum are responsible for rhythmic contractions of papillary muscles of both
ventricles. Since the AV valves have to open simultaneously, interconnections
becomes mandatory as the impulse has to reach it before it reaches the trabeculae
carniae. One of the Posterior papillary muscles is loosely connected to other
papillary muscles, may be the reason for its rupture, more so in left ventricle.
