Left heart volume and left ventricular mass (LV mass) were calculated from biplane cineangiocardiograms in 58 tetralogy of Fallot (TF) patients preoperatively, in 31 patients after shunt procedure, and in 24 patients after complete correction. Preoperatively, the LV end-diastolic volume and left atrial maximal volume (LAmax) were normal in cyanotic infants less than 2.0 years old and in acyanotic patients more than 2.0 years old. These variables, however, were less than normal in cyanotic children > 2.0 years old. Left ventricular ejection fraction (LVEF) and LV systolic index (LVSI) were both less than normal in all groups preoperatively. LV mass was normal preoperatively. After successful shunt procedure, there was a significant increase (P< 0.01) in LVEDV, LVSI, LAmax, and LV mass. The LVEF, however, remained less than normal. After successful corrective surgery, the total group showed a significant increase (P< 0.01) in LVEDV, LVSI, LAmax,and LV mass as compared with preoperative values. Furthermore, the LVEDV was slightly but significantly higher than normal and the LV ejection fraction remained significantly depressed from normal. There was an inverse correlation between LVEDV or LVSI, expressed as a percent of normal, and hemoglobin concentration but not with the net left-to-right shunt or aortic saturation.The decreased LV ejection fraction in cyanotic tetralogy patients in the presence of decreased peak LV pressure (decreased afterload) as well as the decreased LVEF after shunt procedure or complete correction (increased preload) suggests that LV function is depressed in tetralogy patients and remains depressed despite corrective surgery.