 Bartley P. Griffith

Bartley P. Griffith coauthored the 1994 experiment comparing image-derived ventricular area with a balloon-based pressure-volume reference. The publisher's full byline directly verifies the identity. The study used perfused dog hearts, a micromanometer catheter and automated echocardiography to investigate estimates of ventricular compliance.^[ref]

His university profile identifies his professional field as surgery, including heart and lung transplantation and the development of circulatory-support devices.^[ref]

A central issue is the conversion between a geometric surrogate and the mechanical quantity of interest. If volume and area are linked by a differentiable relation $A(V)$, the chain rule givesThe reciprocal slope $dA/dp$ has area-per-pressure units, whereas ventricular compliance $dV/dp$ has volume-per-pressure units. They require a geometric conversion before being interpreted as the same physical quantity.

For an original local example, suppose $dA/dV=0.10\mathrm{c}{\mathrm{m}}^2/mL$ and $dp/dA=2mmHg/c{\mathrm{m}}^2$. Then $dp/dV=0.20$ mmHg/mL and $dV/dp=5$ mL/mmHg. Simply copying the area-pressure inverse slope would give 0.5 square centimetres per mmHg, a different observable.

This illustrates why an experimental reference is valuable even when the surrogate and reference curves have similar shapes. The paper's abstract explicitly confines its conclusion by noting that clinical application remains to be validated.^[ref]