Some Axioms, Popular Notions, and Misconceptions Regarding Cardiovascular Control

Abstract

The present status and future prospects of cardiovascular research have been evaluated in terms of a series of axioms that may serve to summarize this report and to guide our efforts in the future. Axiom I. An important objective of cardiovascular physiology is elucidation of the mechanisms of function and control in animals and human subjects under normal conditions. Axiom II. The use of ambiguous and poorly defined terms tends to obscure ignorance and impede progress. Axiom III. Ideally, investigation of physiologic mechanisms should be conducted with minimal disturbances of either the organ system or its controls. Axiom IV. Experimental data are applicable without reservation only to the specific conditions under which they were collected. Axiom V. Extrapolation in the application of experimental data to species or to conditions of function different from those in which the information was collected should be based on knowledge of the kind and extent of deviation of the experimental from the normal. Axiom VI. The circulation of anesthetized animals must be regarded as experimental models of normal cardiovascular function. Axiom VII. Experimental models are frequently desirable and useful, but their validation requires quantitative comparison of the specific model with the physiologic mechanism or condition it is designed to represent. Axiom VIII. With the development of technics for comprehensive analysis of cardiovascular function in alert, active animals, general anesthesia, thoracotomy, and heart-lung preparations should be less frequently employed for studies of cardiovascular responses. Axiom IX. The use of general anesthesia to perform on animals the same procedures that are routinely accomplished on human subjects with nothing more than topical anesthesia (venipunctures, catheterization, etc.) may complicate interpretation of experimental observations without contributing significantly to the humane treatment of animals. Axiom X. Before extrapolating from one species to another, an investigator has a responsibility to determine to the best of his ability the extent to which appropriate correspondences have been established for the functions or control mechanisms under study. Axiom XI. A scientific term is most useful when it has a unique definition that immediately indicates what characteristics or properties must be quantitatively measured to determine its existence or change in its status. Axiom XII. Changes in function induced by an investigator during physiologic experiments indicate potential rather than actual mechanisms. The responses to artificially induced loads indicate what can happen rather than what does happen during normal spontaneous reactions. Axiom XIII. Although newly discovered natural laws may frequently bring order and clarity out of chaos, simplicity is not a reliable criterion for the validity of postulates regarding physiologic function or control mechanisms.