SWITCH FROM VOLUME PUMP TO PRESSURE PUMP VENTRICLE: A MORPHODYNAMIC STUDY IN THE EUROPEAN EEL (Anguilla anguilla)

Due to its structural and functional plasticity the fish heart ventricle adapts to volume and pressure hemodynamic loads by distinct chamber remodellings (Tota and Gattuso, 1996). This can be best illustrated by ranking elasmobranchs and teleosts on the basis of the relative contribution of pressure and volume to the stroke work. The spectrum of cardiac dynamic patterns obtained allows to distinguish between heart ventricles producing mainly pressure work (prototype: tuna) and those producing mainly volume work (prototype: Antarctic icefish) (Tota and Gattuso, 1996). This adaptational flexibility of the ventricle chamber is also illustrated by some fish species that either by growing or under 60 particular environmental challenges can move from one ventricular pattern to another. As a paradigm of this point we have studied cardiac rearrangements in fresh water eels (Anguilla anguilla). Changes in mechanical cardiac performance and heart morphology relative to body growth were analysed in juvenile (96.8 ± 27.5 g body weight, mean ± SD) and adult (656 ± 12 g bod