AN APPROACH TO VENTRICULAR EFFICIENCY BY USE OF CARBON 11-LABELED ACETATE AND POSITRON EMISSION TOMOGRAPHY

Background. Positron emission tomography-derived C-11-labeled acetate kinetics have been shown to reflect myocardial oxidative metabolism. T he objective of the study was to use this metabolic imaging technique in combination with an evaluation of left ventricular work as an index of ventricular mechanical efficiency. Methods and Results. The effect s of ventricular ejection fraction and loading on this index were stud ied quantitatively in a canine experimental model. There was a curvili near relationship beween efficiency and the end-diastolic volume per u nit mass (r = 0.84), which appeared to integrate the main determinants of left ventricular mechanical performance successfully and allowed t he detection of a decreased ventricular efficiency in acute experiment al heart failure.Conclusions. This approach appears to have the potent ial to assess the energetic working point of the ventricle in clinical heart disease and follow the effects of therapy. The data demonstrate the feasibility of an estimate of ventricular efficiency that relies on noninvasive data-acquisition techniques.