Functional Analysis of the Components of the Right Ventricle in the Setting of Tetralogy of Fallot

Abstract

Background— Anatomic and functional observations suggest that the right ventricle (RV) can be analyzed in terms of its inlet, apical trabecular, and outlet components. Our study was designed to evaluate the regional adaptation of these components to different conditions of loading, with additional analysis of the surgical techniques used for primary repair. Methods and Results— We studied prospectively 45 patients with tetralogy of Fallot (age, 20.5�8.1 years) and 24 control subjects (age, 20.1�5.8 years). All subjects were studied by using cardiac MRI. End-diastolic (EDV), end-systolic (ESV), stroke volumes (SV), and ejection fraction (EF) were determined for the overall RV and separately for its inlet, apical trabecular, and outlet components. The patients had pulmonary regurgitant fractions of 33.2�11.1%, and RV peak-systolic pressures of 40.7�16.1 mm Hg. In controls, the apical trabecular component EDV was 51.5�11.1 mL/m 2 (54.3�6.8% of the total RV EDV), ESV was 19.2�6.3 mL/m 2 (47.6�10.5% of RV ESV), and SV was 32.3�6.9 mL/m 2 (58.9�6.6% of RV SV), resulting in an EF of 63.1�7.7%. When considering all patients, the apical trabecular component took up the greatest part of the overload, having an EDV of 76.5�18.1 mL/m 2 , and an ESV of 31.6�12.8 mL/m 2 , reflecting an increase of 49 and 67% over controls, respectively ( P <0.001). EF was 59.7�10.7%, and was maintained at control levels ( P =0.132). In controls, the outlet had considerable ejecting force, with an EF of 54.8�9.1%, whereas it was decreased in the patients with tetralogy (EF=28.5�11.9%). There was significant increase of ESV ( P <0.001), but not of EDV, with EF decreased by 45% ( P <0.001). The inlet was not significantly affected by overload. The surgical technique did not significantly affect any measured parameter for any component. Conclusions— In patients with tetralogy of Fallot, subsequent to surgical correction, the individual components of the RV respond in characteristic fashion to RV overload.

Pulmonary Annular Motion Velocity Assessed Using Doppler Tissue Imaging – Novel Echocardiographic Evaluation of Right Ventricular Outflow Tract Function –

“…Although in the normal heart it is reported that the function of the inflow and outflow components of the RV can be closely related, 16 this relationship would be weak and unpredictable in patients with TOF. 17 Our study also demonstrated a significant correlation between pulmonary and tricuspid annular motions in the peak velocities of the s1' and e' trols (P<0.001, P<0.05, P<0.001 and P<0.05, respectively).…”

Torsional Mechanics of the Left Ventricle in Patients After Surgical Repair of Tetralogy of Fallot

“…While the exact mechanism remains to be elucidated, the recent report of differential response of the three RV components to volume overload in the setting of TOF mighty shed some light on a possible explanation. 19 In the aforementioned study, the RV apical component, as a contrast to the inlet and outlet components, has been shown to take up the greatest part of the volume load secondary to pulmonary regurgitation while providing the major ejectile momentum of the ventricle. Disproportional enlargement of the RV apical trabecular component might potentially exert more prominent effects on LV apical rotation because of the ventricular-ventricular interaction.…”

Pulmonary Vascular Resistance, Collateral Flow, and Ventricular Function in Patients With a Fontan Circulation at Rest and During Dobutamine Stress

“…12,19,20 Sequence parameters were TR and TE, 3.4 and 1.7 milliseconds; slice thickness, 6 mm; no gap; in-plane resolution, 1.9ϫ1.3 mm 2 ; 45 phases per cardiac cycle; number of averages, 1; and sensitivity encoding reduction factor, 2. Analysis was done using View Forum release 6.1 software.…”