On the Influences which Modify the Work of the Heart*

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

“…21 In 1879, Charles Smart Roy, one of Foster's pupils, described the dependence of the work of the frog heart on diastolic volume (Figure 1). His report, published the follow-ing year, 22 acknowledges a "debt of gratitude" to Kronecker, one of Ludwig's pupils. Roy's work showed that "at constant aortic pressure and heart rate, the [work of the heart] is capable of being varied within wide limits by variations in the venous pressure," and concluded that "we must look to the quantity of blood arriving at the heart as the predominating factor in regulating the work done."…”

“…If this be so, and there is every reason to believe in the truth of the generally accepted opinion (italics added), it follows that the quantity of blood thrown out at each systole will depend on the degree of distension assumed by the relaxed ventricle. 22 A decade later, Roy and Adami, 23,24 showed that the output of the mammalian heart increases when blood volume is increased and decreases when blood is removed from the circulation. 24 They also observed that a rise in aortic pressure "does not change the amount of blood thrown out by the heart" because when aortic pressure is increased, the "size [of the heart] at the end of systole is greater than with normal arterial pressure."…”

“…23 In 1897, Starling 25 mentioned Roy and Adami's finding that end-diastolic volume is increased by a rise in arterial pressure or increased venous return, but did not cite Roy's 1879 paper. 22 William Henry Howell and Frank Donaldson, Jr, who were trained at Johns Hopkins by one of Foster's students, studied the regulation of stroke volume in the mammalian heart. In their 1884 paper, 26 they reported that "the work done by the left ventricle at each systole increases with the venous pressure" (Figure 2).…”

Identification of the Time-Varying Ventricular Parameters During the Ejection Phase of the Cardiac Cycle: The Martingale Optimality Principle Approach

“…The ejection of blood from the heart is influenced by its filling, physiologic status, and the receiving arterial system (load), aspects recognized since [1]. Furthermore, the contractile properties of the ventricle represent good diagnostic tools for many heart diseases [2,3].…”