Heart ventricle pumps in teleosts and elasmobranchs: a morphodynamic approach

Structural restrictions and functional plasticity related to different heart ventricle myoarchitectures have been analyzed in fish. Two aspects have been considered: the first concerns the relationships between the structural design of the ventricular pump and its mechanical behavior; the second considers the impact of the ventricular architecture on some hydraulic aspects of coronary flow. Stroke work measures the combination of pressure and volume work performed by the cardiac pump. When several elasmobranchs and teleosts are ranked on the basis of the relative contribution of pressure and volume to the stroke work, a spectrum of dynamic cardiac patterns is obtained. Thus, it is possible to distinguish between ventricles producing mainly pressure work and those producing mainly volume work. Most species, including elasmobranchs, are located between these two extremes. Indicative examples, such as tuna and icefish, show the existence of a definite relationship between the myoarchitecture of the ventricle and the mechanical behavior of the whole heart expressed in terms of pressure generation and volume movement. Regardless of neurohumoral or metabolic regulation, the different coronary flow profiles, such as those detected in salmonids and elasmobranchs, appear closely related to the myo‐angioarchitecture of the ventricular wall. The importance of internal morphological determinants, which cannot simply be explained as adaptations to special life‐style patterns but result from the morphoconstructional aspects of the internal cardiac machinery, is emphasized