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By John Gorcsan III, William A. Mandarino, Lee G. Deneault, Shigeki Morita, Akihiko Kawai, Bartley P. Griffith, Robert L. Kormos. The International Journal of Cardiac Imaging 10, 103–111, June 1994. Publisher title, full byline, author affiliations and abstract verified at link.springer.com/article/10.1007/BF01137705 . Abstract: six excised dog hearts were perfused ex vivo; an intraventricular balloon supplied volume and a micromanometer catheter supplied pressure. Automated echocardiographic borders measured mid-ventricular short-axis area. Three volume runs in 1 mL increments per heart yielded 1,080 simultaneous observations. The experiment compared pressure-area with pressure-volume relationships; it did not establish clinical validation. Full article not inspected.

Robert L. Kormos is a named coauthor of the 1994 primary study estimating ventricular compliance from automated echocardiography and pressure measurements. The publisher supplies the full name and describes the shared isolated-heart measurement experiment.^[ref]

The apparatus makes the reference quantity unusually concrete: an intraventricular balloon supplies known volume changes, rather than inferring every volume from the same image being tested. A micromanometer records pressure, and a computer interface pairs it with short-axis ventricular area.

An original calibration example separates absolute volume from its increments. If a reference has a fixed offset $V_m=V+b$, then $\Delta V_m=\Delta V$ and $d{V}_m/dp=dV/dp$. The offset does not disappear from the reported absolute volumes. If instead $V_m=gV+b$, the inferred ventricular compliance is multiplied by $g$. With true compliance 4 mL/mmHg and $g=1.05$, it becomes 4.2 mL/mmHg. Agreement about increments is therefore different from agreement about the curve's absolute location.

The primary experiment varied balloon volume repeatedly and compared image-area and volume-based pressure relations. Its favorable experimental correspondence and explicit need for clinical validation document a methodological contribution, without establishing an identical result for every chamber or loading condition.^[ref]