Patients with Tetralogy of Fallot have lower systolic KE in the left ventricle and higher diastolic KE in the right ventricle
© Sjöberg et al. 2016
Published: 27 January 2016
There is a persisting debate regarding indications and timing of pulmonary valve replacement in patients with pulmonary insufficiency after repair of Tetralogy of Fallot (ToF). The status of right ventricular function is important is this decision but remains elusive. 4D-flow CMR enables quantification of ventricular kinetic energy (KE) which may provide improved understanding of the pathophysiology of the dilated ventricle with impaired function. In this study we wanted to quantify ventricular KE in patients with pulmonary insufficiency after repair of ToF.
Nine patients with pulmonary insufficiency after repair of ToF (3 females, median age 22 years, range 18-51) underwent cardiovascular magnetic resonance (CMR) with a 1.5 T Philips scanner including four-dimensional phase-contrast flow sequence. Eight healthy volunteers (2 females, median age 26, range 23-36) were used as controls. Ventricular segmentation was performed in cine ssfp images, 30 time frames per cardiac cycle covering the heart and imported to the 4D flow dataset. Ventricular KE calculated as KE=½mv² was summed over all voxels inside the right and left ventricle and calculated for each time frame.
ToF patients have decreased left ventricular systolic KE compared to controls, indicating left ventricular affection in ToF patients, possibly through septal dyssynchrony. During diastole, right ventricular KE is increased compared to controls, most likely caused by the pulmonary regurgitation. Thus, 4D-flow MRI offers new insights in ToF physiology and inter-ventricular interaction.
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