Assessment of Right Ventricular Volume in Tetralogy of Fallott (TOF) Patients

Assessment of Right Ventricular Volume using the VentriPoint Medical system in patients with Tetralogy of Fallot following repair; a comparison study to cMRI. The objective of this study is: To evaluate the accuracy of the VentriPoint Medical System to calculate right ventricular volumes in patients with Tetralogy of Fallot following surgical repair. Secondary objectives are: To validate Inter and Intra observer variability at 3 clinical sites. The analyses will be the same for EDV and ESV. For either right ventricular volume, the primary effectiveness measure is the % difference between VMS and cMRI results, i.e. (VMS-cMRI)\*100%/average of VMS and cMRI results. There will be two null hypotheses for the primary analysis: H0+: true mean % difference \> 10% and H0-: true mean % difference \< -10% The observed mean % difference will be presented with 95% confidence intervals. The VMS right ventricular volume estimates will be regarded as equivalent to cMRI estimates if both H0+ and H0- are rejected at a 1-sided 0.025 level by a paired t test for both EDV and ESV. Since H0+ and H0- cannot both be true, the total type I error rate for each measure is 0.025 and the overall type I error rate for both EDV and ESV is 0.05.