Ernest Henry Starling, His Predecessors, and the “Law of the Heart”

The discovery that end-diastolic volume regulates the work of the heart is generally credited to Ernest Henry Starling, who described this relationship in a series of papers between 1912 and 19141–4⇓⇓⇓ and in his Linacre Lecture, which was given at Cambridge University in 1915 and published in 1918.5 In these papers, Starling and his collaborators acknowledge that they were not the first to describe this relationship6; they cite the work of Blix7 and Evans and Hill8 on the length-dependence of energy release by skeletal muscle, Frank’s 1895 description of the influence of diastolic volume on the work of the frog ventricle,9 and contemporary descriptions in canine10 and feline hearts.11 The present article reviews evidence that what we now call “Starling’s Law of the Heart” or “The Frank-Starling Relationship” was widely appreciated by late 19th century physiologists. Starling’s Law of the Heart is a manifestation of the length-tension relationship seen in skeletal muscle, which was well known to physiologists during the second half of the 19th century. This relationship was discovered in 1832 by Schwann; Needham, who described this history,12 stated that Schwann’s discovery “caused a great sensation among physiologists of the time,” in part because this discovery was made at a time when muscle performance was being analyzed in terms of the then new science of thermodynamics. That contracting muscles liberate energy as both work and heat was first noted by Helmholtz, whose 1848 description of heat production by muscle “… lighted a flame which… burnt brightly in Germany till the end of the [19th] century.”13 Recognition of the role of rest length in determining energy release by skeletal muscle led to studies of cardiac energetics during the second half of the 19th century. ### Diastolic Volume and the Work of the Heart #### Early German Contributions Carl Ludwig …