Transfer function analysis of the ventricular function: a new method for calculating right ventricular ejection fraction.

The relationship between the ventricular transfer function and ejection fraction has been investigated by the routine procedure of first-pass radionuclide angiocardiography. Ejection fraction has been shown to equal 1-e(-b), where b is the ratio of the R-R interval over the mean transit time difference between ventricular and atrial time-activity curves. To evaluate the effect of region of interest (ROI) on the right ventricular ejection fraction (RVEF), the results of the transfer function analysis (TFA) technique using precise ROI, TFA using rectangular ROI, and the routine method were compared. Regression analyses among RVEFs obtained from the above ROI methods yielded good correlations. Reliable RVEFs have been obtained even in the case of an improper bolus injection. Thus, the TFA technique is a new, simple, and reliable method for calculating RVEF without needing to outline the right ventricle precisely.