Speckle Tracking Echocardiography before and after Surgical Pulmonary Valve Replacement in Tetralogy of Fallot Patients: Can STE Elucidate Early Left Ventricular Dysfunction?

Background:
Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Most studies have focused on Right Ventricular (RV) dysfunction, while the left ventricle has received less attention in patients with TOF.
Objectives:
This study aimed to investigate the Left Ventricular (LV) function after surgical Pulmonary Valve Replacement (sPVR) in patients with repaired TOF (rTOF) by Speckle Tracking Echocardiography (STE).
Methods:
This single-center, observational, cross-sectional study was conducted on 58 volunteers (age: 15 - 31 years) divided into three groups as follows: 22 PVR patients (mean age: 18.96 ± 7 year), 16 patients with rTOF, and 20 healthy controls who were matched regarding the PVR age range. 2D echocardiography (including Doppler and M-Mode indices of the right and left ventricles) and Speckle Tracking Echocardiography (STE) (Global Longitudinal Strains (GLS) and 18 segment analyses) were performed for all patients. All analyses were done using the SPSS software and P < 0.05 was considered to be statistically significant.
Results:
2D echocardiography showed normal LV Ejection Fraction (LVEF) in all study groups (64% in sPVR, 60% in rTOF (P = 0.127), and 62.5% in the control group). However, the mean GLS of the left ventricle significantly reduced in both sPVR (-17.5 ± 2.5%) and rTOF (-17.1 ± 4.7%) patients in comparison to the control group (-20.2 ± 0.7%) (P = 0.003). Yet, no significant difference was observed between the rTOF and sPVR groups regarding the GLS (P = 0.9).
Segmental analysis of the Longitudinal Strain (LS) indicated a significant decrease in the sPVR and rTOF groups in basal anterior, basal septal, basal anterolateral, mid-anterior, and anterolateral segments. Except for the lower LS in the apical-anteroseptal segment, this level was mostly spared in both sPVR and rTOF patients.
Conclusions:
LVEF was within the normal range among the sPVR patients, but the pattern of impaired segmental LS and GLS did not change compared to the rTOF group. In conclusion, sPVR might not have a significant effect on the improvement of LV function assessed by STE in patients with rTOF. LV damage occurring during the surgical correction of TOF might have a permanent deteriorating effect on LV function.