Abnormalities in Left Ventricular Rotation Are Inherent in Young Children with Repaired Tetralogy of Fallot and Are Independent of Right Ventricular Dilation

Left Ventricular Torsion Obtained Using Equilibrated Warping in Patients with Repaired Tetralogy of Fallot

Patients after surgical repair of Tetralogy of Fallot (rTOF) may suffer a decrease in left ventricular (LV) function. The aim of our study is to evaluate a novel method of assessing LV torsion in patients with rTOF, as an early indicator of systolic LV dysfunction. Motion tracking based on image registration regularized by the equilibrium gap principle, known as equilibrated warping, was employed to assess LV torsion. Seventy-six cases of rTOF and ten normal controls were included. The group of controls was assessed for reproducibility using both equilibrated warping and standard clinical tissue tracking software (CVI42, version 5.10.1, Calgary, Canada). Patients were dichotomized into two groups: normal vs. loss of torsion. Torsion by equilibrated warping was successfully obtained in 68 of 76 (89%) patients and 9 of 10 (90%) controls. For equilibrated warping, the intra- and interobserver coefficients of variation were 0.095 and 0.117, respectively, compared to 0.260 and 0.831 for tissue tracking by standard clinical software. The intra- and inter-observer intraclass correlation coefficients for equilibrated warping were 0.862 and 0.831, respectively, compared to 0.992 and 0.648 for tissue tracking. Loss of torsion was noted in 32 of the 68 (47%) patients with rTOF. There was no difference in LV or RV volumes or ejection fraction between these groups. The assessment of LV torsion by equilibrated warping is feasible and shows good reliability. Loss of torsion is common in patients with rTOF and its robust assessment might contribute into uncovering heart failure in an earlier stage.

Impact of pulmonary valve replacement on left ventricular rotational mechanics in repaired tetralogy of Fallot

BACKGROUND

In repaired tetralogy of Fallot (rTOF), abnormal left ventricular (LV) rotational mechanics are associated with adverse clinical outcomes. We performed a comprehensive analysis of LV rotational mechanics in rTOF patients using cardiac magnetic resonance (CMR) prior to and following surgical pulmonary valve replacement (PVR).

METHODS

In this single center retrospective study, we identified rTOF patients who (1) had both a CMR ≤ 1 year before PVR and ≤ 5 years after PVR, (2) had no other intervening procedure between CMRs, (3) had a body surface area > 1.0 m2 at CMR, and (4) had images suitable for feature tracking analysis. These subjects were matched to healthy age- and sex-matched control subjects. CMR feature tracking analysis was performed on a ventricular short-axis stack of balanced steady-state free precession images. Measurements included LV basal and apical rotation, twist, torsion, peak systolic rates of rotation and torsion, and timing of events. Associations with LV torsion were assessed.

RESULTS

A total of 60 rTOF patients (23.6 ± 7.9 years, 52% male) and 30 healthy control subjects (20.8 ± 3.1 years, 50% male) were included. Compared with healthy controls, rTOF patients had lower apical and basal rotation, twist, torsion, and systolic rotation rates, and these parameters peaked earlier in systole. The only parameters that were correlated with LV torsion were right ventricular (RV) end-systolic volume (r = - 0.28, p = 0.029) and RV ejection fraction (r = 0.26, p = 0.044). At a median of 1.0 year (IQR 0.5-1.7) following PVR, there was no significant change in LV rotational parameters versus pre-PVR despite reductions in RV volumes, RV mass, pulmonary regurgitation, and RV outflow tract obstruction.

CONCLUSION

In this comprehensive study of CMR-derived LV rotational mechanics in rTOF patients, rotation, twist, and torsion were diminished compared to controls and did not improve at a median of 1 year after PVR despite favorable RV remodeling.

Left ventricular rotational abnormalities in adult patients with corrected tetralogy of Fallot following different surgical procedures (Results from the CSONGRAD Registry and MAGYAR-Path Study)

Background

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease (CHD). Abnormal aortic dimensions and elasticity parameters have been long described for corrected TOF (cTOF) together with left ventricular (LV) rotational abnormalities, but results are conflicting. The present study focuses on investigating LV rotational mechanics in cTOF, and possible correlation of these parameters with aortic elasticity. It was also aimed to be examined whether different surgical strategies have any effect on these results.

Methods

The study involved 26 adult cTOF patients, from which 14 had palliative surgery first and a late total correction (pcTOF), while early total correction was the treatment of choice in 12 patients (etrTOF). Their results were compared to those of 37 age- and gender-matched healthy adults. Routine transthoracic two-dimensional Doppler echocardiography extended with assessment of aortic elastic properties and three-dimensional speckle-tracking echocardiography (3DSTE) was performed in all cTOF patients and controls.

Results

Sixteen out of 26 cTOF patients showed normally directed LV rotational mechanics, while apical or basal LV rotations were in the same clockwise or counterclockwise directions in 7 and 3 cTOF cases, respectively (LV 'rigid body rotation', RBR). Significantly reduced LV apical rotation and twist could be demonstrated in all cTOF patients with preserved LV basal rotation regardless of previous procedure. pcTOF patients showed significantly reduced LV apical rotation as compared to that of etrTOF cases. Significant correlations could be demonstrated between LV apical rotation and aortic stiffness index (r=-0.55, P=0.03) and aortic distensibility (r=0.52, P=0.04).

Conclusions

Significant LV rotational abnormalities could be demonstrated in cTOF with the high prevalence of LV-RBR. pcTOF patients showed significantly reduced LV apical rotation as compared to that of etrTOF cases. Unexpected abnormal physiologic response of LV rotational mechanics to increased aortic stiffness can be detected in cTOF patients without LV-RBR.