BACKGROUND Total cavopulmonary connection has been proposed as a rational alternative to atriopulmonary connection for complex Fontan operations. In addition to fluid dynamic advantages proposed by de Leval, total right heart bypass may address an emerging important issue after repair of single ventricle: late atrial arrhythmias. The purpose of this study is to document the postoperative hemodynamic findings in 22 consecutive patients who received a total extracardiac right heart bypass with an inferior vena cava-to-pulmonary artery extracardiac Dacron conduit with a modified Glenn anastomosis (superior vena cava-to-pulmonary artery anastomosis). RESULTS Twenty-eight patients with complex congenital heart disease underwent this surgical procedure. One patient died (early mortality, 3.5%). Mean follow-up was 13.9 months. Postoperative cardiac catheterization and echo Doppler studies were performed in 22 of the 27 survivors. In 18 of 22 patients, hemodynamic data were satisfactory; a preferential direction of caval flows to both lungs was observed. Echo Doppler assessments show that forward cavopulmonary flow appears as a predominant early diastolic event, in contrast to what occurs in atriopulmonary connections. This hemodynamic model emphasizes the possible role of the diastolic ventricular performance (as a "suction pump") in Fontan circulation. Early postoperative atrial arrhythmias were observed in two of the survivors. CONCLUSIONS The technical advantages and the hemodynamic benefits of this form of right heart bypass are encouraging. Although the use of artificial material in this procedure is extensive, none of the survivors showed thromboembolic complications or peel formations with narrowing and/or obstruction. Further investigations during a longer follow-up are needed to confirm the early and intermediate results, especially the reduction of late atrial arrhythmias.