Differential Adaptation of Biventricular Myocardial Kinetic Energy in Patients With Repaired Tetralogy of Fallot
Shi-Ying Ke1, Ken-Pen Weng2,3, Meng-Chu Chang1
1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan.
Background:
The myocardial kinetic energy (KE) and its association with pulmonary regurgitation (PR) have yet to be investigated in repaired tetralogy of Fallot (rTOF) patients.
Purpose:
To evaluate the adaptation of myocardial KE in rTOF patients by tissue phase mapping (TPM).
Study Type:
Prospective.
Population:
A total of 49 rTOF patients (23 ± 5 years old; male = 32), 47 normal controls (22 ± 1 year old; male = 29).
Field Strength/Sequence:
3-T/2D dark-blood three-directional velocity-encoded gradient-echo sequence.
Assessment:
Left and right ventricle (LV, RV) myocardial KE in radial (KEr ), circumferential (KEø ), longitudinal (KEz ) directions. The proportions of KE in each direction to the sum of all KE (KErøz ): %KEr , %KEø , %KEz . PR fraction.
Statistical Test:
Student's t test, multivariable regression. Statistical significance: P < 0.05.
Results:
In rTOF group, LV KEz remained normal in systole (P = 0.565) and diastole (P = 0.210), whereas diastolic LV %KEz (62% ± 14% vs. 72% ± 7%) and systolic LV %KEø (9% ± 6% vs. 20% ± 7%) were significantly decreased. The KEr and %KEr of both ventricles significantly increased in the rTOF group (RV in diastole: 6 ± 3 vs. 3 ± 1 μJ and 54% ± 13% vs. 27% ± 7%). The rTOF group exhibited significantly higher RV/LV ratios of %KEr (systole: 1.3 ± 0.3 vs. 1.0 ± 0.3) and %KEø (systole: 1.6 ± 0.8 vs. 1.0 ± 0.3) and significantly lower ratios of %KEz in systole (0.7 ± 0.2 vs. 1.0 ± 0.1) and diastole (0.5 ± 0.2 vs. 0.9 ± 0.1). In multivariable regression analysis, the RV peak systolic KErøz , RV systolic KEz , and LV diastolic %KEø were independently associated with PR fraction in the rTOF group (adjusted R2 = 0.479).
Data Conclusion:
In rTOF patients, the adaptation of the KE proportion occurred earlier than that of the KE amplitude, and the biventricular balance of %KE was disrupted. PR may cause differential KE adaptation in RV and LV. TPM-derived KE may be useful in investigation of myocardial adaptation in rTOF patients.
Evidence Level:
2 TECHNICAL EFFICACY: Stage 3.
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