Isaac "Jack" Starr (March 6, 1895 – June 22, 1989), known as the father of ballistocardiography,[3][4] was an American physician, heart disease specialist, and clinical epidemiologist notable for developing the first practical ballistocardiograph.

[5] At the request of Richards, Starr became one of the first assistant professors at the University of Pennsylvania School of Medicine in 1928, doing research which used physics and mathematics in the study of the heart,[2] and leading a course in clinical pharmacology for the medical students.

This project, a suspended bed rigged with springs to pick up resonance frequencies and amplify them, inspired Starr to develop a practical version for use in his own research, with the help of the Eldridge Reeves Johnson Foundation for Medical Physics.

"[12] During World War II, Isaac Starr and Dr. Eugene A. Stead were members of a committee of the National Research Council that was tasked with deciding which chemicals and medications were considered important to medicine.

[12] Starr was one of the first people to suggest that venous congestion was related to the volume of blood and the muscle tone of the vessels, while a weakened heart's contributions were less important than previously thought.