Abstract 1940: Diastolic Untwisting is Altered in Tetralogy of Fallot Patients: A Novel MR Speckle Tracking Method for Cine-MRI
Background: In tetralogy of Fallot (TOF), satisfactory post-op outcome is not solely dependent on systolic right and left ventricular (RV,LV) function. Early signs of LV diastolic dysfunction need to be studied in this patient group.
Methods: We studied 15 patients with TOF (6mon-45y) post repair and 8 healthy adults (24 –35y). MR images were acquired with an ECG gated 1.5/3T Magnet with segmented gradient-echo cine-loop sequences (short/long/rotated axis) to cover the entire RV and LV. Images were analyzed offline by VVI (Siemens). RV size and function were correlated for each patient by 4D analysis (TomTec) of RV volumes and ejection fraction; LV myocardial strain, direction of twist and untwisting, time to peak twist and time to peak diastolic untwisting were measured.
Results: In healthy controls, LV strain was measured at −18.5% ± 7% and twist at −9.6° ± 4.3° (p ≤ 0.05); time to peak systolic twist was less heterogeneous and twist direction uniformly counterclockwise (ccw). Also, time to peak diastolic untwisting was significantly longer (320ms ± 120ms) in normals than in the TOF group. In the TOF group, decreases in LV strain (m −11.4% ± 4.6%), and twist (m −6.4° ± 3.6°) were found. Time to peak ccw systolic twist was prolonged and more heterogeneous in TOF patients than in controls. Time to peak diastolic untwisting was decreased and more variable in TOF patients (m 140ms ± 85ms, p ≤ 0.05).
Conclusions: The degree and duration of both systolic twisting and diastolic untwisting are abnormal in post-op TOF patients, as are time to peak and duration of diastolic untwisting.