LATE VENTRICULAR GEOMETRY AND PERFORMANCE CHANGES OF FUNCTIONAL SINGLE VENTRICLE THROUGHOUT STAGED FONTAN RECONSTRUCTION ASSESSED BY MAGNETIC-RESONANCE-IMAGING

Objectives. We sought to test the hypothesis that late ventricular geo metry and performance changes occur in functional single ventricles as they progress through staged Fontan reconstruction. Background. Index es of ventricular geometry and performance are important in evaluating the functional state of the heart, Magnetic resonance imaging determi nes these indexes in complex ventricular shapes with minimal geometric assumptions. Previous studies have shown that 1 week after hemiFontan , the mass/volume ratio markedly increases. Methods. Multiphase, multi slice, spin echo (n = 5) and cine (n = 30) magnetic resonance imaging was performed in 35 patients with a functional single ventricle (1 wee k to 12 years old) at various stages of Fontan reconstruction (15 in t he pre hemiFontan stage, 11 after [6 to 9 months] the hemiFontan proce dure and 9 after [1 to 2 years] the Fontan procedure). Volume and mass were calculated at end-systole and end-diastole. Ventricular output w as then obtained. Ventricular centroid motion was also calculated. Res ults. No difference was noted (power >72%) from the pre-hemiFontan sta ge to 6 to 9 months after the hemiFontan procedure in (mean +/- SD) en d-diastolic volume (104 +/- 24 vs. 123 +/- 40 cc/m(2)), mass (171 +/- 46 vs. 202 +/- 61 g/m(2)), ventricular output (7.9 +/- 2.2 vs. 6.6 +/- 2.4 liters/min per m(2)) or centroid motion (6.9 +/- 2.8 vs. 6.7 +/- 2.6 mm/m(2)). Patients in the Fontan group demonstrated a marked decre ase in all indexes, indicating significant volume unloading and decrea se in mass and ventricular performance. Mass/volume ratio,vas not sign ificantly different among all three groups. Conclusions. No geometric and performance changes from the volume loaded stage are noted 6 to 9 months after the hemiFontan procedure; however, major changes occur 1 to 2 years after the Fontan procedure. The dramatic changes in the mas s/volume ratio seen early after the hemiFontan procedure were not dete cted at 6 to 9 months. Furthermore, diminution of mass, volume and ven tricular performance are present at least 2 years after the Fontan pro cedure.