[Phase imaging of isotopic ventriculographies: contribution to the study of the Wolff-Parkinson-White syndrome].

This study compared the phase images of 12 normal subjects and 14 patients with right ventricular and 5 patients with left ventricular preexcitation. The phase images obtained from equilibrium radionuclide ventriculographies in the left anterior oblique portion with an ECG trigger: Fourier analysis was used to measure the phase and amplitude of the variations. In normal subjects the mean difference in phase was nearly zero: in 12 of the 14 patients with right ventricular preexcitation, right ventricular preceded left ventricular contraction (LV phase - RV phase = + 23 degrees); injection of Ajmaline normalised the ECG and suppressed the premature right ventricular contraction during right ventricular preexcitation (LV phase - RV phase = nearly zero), demonstrating a direct relationship between the abnormal depolarisation and abnormal contraction. In left sided Kent bundles, phase imaging did not seem to show significant premature ventricular contraction under basal conditions. Atrial pacing, which accentuated both left and right electrical preexcitation, increased the difference in ventricular phase. Finally, a satisfactory correlation was observed between the presumed locations of the accessory pathways and the zones of premature right and left ventricular contraction.