Abstract 6070: Alterations of Left Ventricular Strain and Twist as Relates to RV Size in Patients with Tetralogy of Fallot Studied by Gradient-Echo Cine MRI: Delineation of Ventricular/Ventricular Interaction
Our goal was to analyze myocardial tissue strain and twist in patients with post op tetralogy of Fallot (TOF) using a novel MR speckle tracking method for MR gradient-echo loops as relates to right ventricular (RV) size. We studied 25 patients with TOF (6mo-14yrs) and 10 healthy adults (24 –35 yrs). All MRI images were acquired with an ECG gated 3T Magnet with segmented gradient-echo cine-loop sequences (short/long axis/rotated) to cover the entire RV and left ventricle (LV). All images were analyzed offline by vector velocity imaging (VVI, Siemens) and TomTec RV 4D analysis. RV size, function and myocardial strain and twist were correlated in each patient. LV myocardial circ strain was measured at -9% to -15% in TOF patients along with septal dyssynchrony. A marked decrease in LV twisting to −2° to −7° (m −4° ±3°) and loss of septal twist initiation were found. RVEF was measured between 35– 46%; EDV was 45.3ml to 95.3ml while ESV was 29.4ml to 63.4ml. There was a close correlation between loss of circular strain and twist initiation with 4D measured RV size and RVEF. In healthy adults measured circ strain was -19% to -26% with highest values in the septal and inferior area (-26% ±6%) and lower values at the anterior free wall; they also exhibited a natural counterclockwise LV twist of − 6° to −14° (m −7° ±4°) with twisting starting in the septal area. RVEF was measured between 48 –59%. RV EDV was measured at 28ml to 63ml, ESV at 10.4 ml to 42ml in controls. This clinical study indicates that septal dysfunction exists in patients post repair TOF. A negative correlation exists between RV size and LV myocardial strain and twist in TOF patients.