Leonardo da Vinci and the first hemodynamic observations.

Leonardo da Vinci was a genius whose accomplishments and ideas come down to us today, five centuries later, with the freshness of innovation and the fascination of discovery. This brief review begins with a summary of Leonardo's life and a description of the most important works of art that he bequeathed us, and then concentrates on his last great challenge. There was a point at which Leonardo's passion for art gave way to the study of human anatomy, not only to improve his drawing but to go beyond what had been simply a representation of form to understand the underlying functioning. Among his many interests, we focus on his study of the heart and blood vessels, which he observed carefully in animals and human autopsies, and reproduced in drawings of great quality with annotations of astonishing acuteness. The experience that he had acquired from observing the flow of water in currents and around obstacles, and the conclusions that he drew concerning hydrodynamics, were central to his interpretation of the mechanisms of the heart and of blood flow, to which he devoted much of his time between 1508 and 1513. From these studies, immortalized in drawings of great clarity, come what are acknowledged to be the first hemodynamic records, in which Leonardo demonstrates the characteristics of blood flow in the aorta and great vessels and the importance of blood reflux and the formation of eddies in the sinus in aortic valve his assiduous and careful observations, and his subsequent deductions, Leonardo put forward detailed findings on hemodynamic questions that advanced technology has only recently enabled us to confirm.