Does Fourier phase shift correlate with conduction delay in bundle branch block?

Abstract

Fourier analysis of radionuclide ventriculography is adept at qualitatively demonstrating interventricular conduction delay in bundle branch block. In this study of eighteen patients, there is a considerable individual variation when the phase delay is expressed as an absolute conduction delay (milliseconds). Much of this variability persists after curve representation by the Fourier function has been optimized. It is suggested that this variability is due to differences in the shape of the right and left ventricular time-activity curves, reflecting differences in contraction and relaxation in the two ventricles. Such differences may be more pronounced in some subjects than others. These results suggest that absolute conduction delay cannot be reliably achieved by this method.