Radionuclide Assessment of Left and Right Ventricular Functions in Patients With Tetrology of Fallot

Using 10-15 mCi 99mTc-Iabelled red blood cells, ECG-gated radionuclide ventriculography was performed in 16 cyanotic pediatric patients with tetralogy of Fallot to assess the right and left ventricular function. Phase and amplitude analysis of scintigraphic images and multiharmonic Fourier analysis of time activity curve were generated. Mean ejection fraction (EF) of right and left ventricles were 28±11 % and 48.9±10 %, respectively. 50 % of patients had decreased right ventricular EF values. Systolic and diastolic functional parameters were also calculated. Right ventricular 1/3 EF, 1/3 FF (filling fraction), PER (peak ejection rate), 1/3 ER (ejection rate), 1/3 FR (filling rate) values were lower than those of normals (p<0.005). 1/3 FF value of left ventricle was decreased in comparison to normal (p<0.05). TPE (time to peak ejection)/TPF (time to peak filling) and PER/PFR ratios were increased.Systolic ejection time interval of right ventricle was prolonged and difference of phase angle among two ventricles was increased. Right ventricular standard deviation of phase histogram was enlarged. TPE/T values were higher than normals for both ventricles. TPF/T values were in the normal range. Systolic and diastolic parameters used in the present study may be valuable for the quantative evaluation of the right and left ventricular function.