The study of the cardiovascular system dates back to the anatomic descriptions and speculations of Antiquity. Little progress was made during the Middle Ages and early Renaissance, until the birth of hemodynamics with William Harvey’s groundbreaking discovery of the circulation in 1628, based on experimentation and, to some extent, shrewd hypothesis, as without the microscope he had no proof of the existence of the capillary system. The mercury manometer was invented in 1828 by Jean-Louis Poiseuille. The pioneering work of 19th-century physiologists such as Karl Ludwig, Otto Frank, and Ernest Starling was followed by that of 20th-century clinicians like Helen Taussig, Alfred Blalock, Maude Abbott, and André Cournand. More recent milestones include the advent of investigational catheterization, culminating in percutaneous catheter-based methods for the treatment of certain forms of heart disease...