A unifying representation of ventricular volumetric indexes

We studied volumetric characteristics of the ventricle in various hearts covering a wide (patho)physiological range, using the individual operating point at basal conditions. The aim of this analysis is to formulate a unifying relationship between volumetric parameters which will be applicable to cardiac ventricles regardless of underlying pathology. Analyzing our own measurements as well as additional data published elsewhere indicates that end-systolic volume (ESV) versus end-diastolic volume (EDV) yields a high linear population based correlation coefficient. This analytical expression can subsequently be used for the evaluation of clinically relevant derived indexes. For example, the new approach permits estimation of important physiological quantities such as stroke work and myocardial oxygen consumption, while isopleths and regions with equal ejection fraction can all be inscribed as linear relationships within a single graph. Based on statistical considerations, we demonstrate that in terms of correlation this new graphical representation is superior to the curve relating output (stroke volume) to input (preload) of the ventricle. We conclude that the ESV versus EDV representation facilitates insight into cardiac volumetric behavior and permits prediction of clinically relevant cardiodynamic effects, as produced by ventricular dimensional changes, for example induced by surgical or pharmacological intervention, or by the progression of cardiac disease.