Use of Speckle Tracking Echocardiography to Assess Left Ventricular Systolic Function in Patients with Surgically Repaired Tetralogy of Fallot: Global and Segmental Assessment

Abstract

Patients with repaired Tetralogy of Fallot (rToF) can have significant right and left ventricular dysfunction which can impact clinical outcome. Conventional echocardiographic evaluation using ejection fraction can be limited in detecting early stages of deteriorating left ventricular (LV) systolic function. Speckle-tracking echocardiography (STE) provides a promising emerging tool for early detection of LV systolic dysfunction. The aim of this cross-sectional study is to evaluate the left ventricular global and regional function using STE in rToF patients with preserved left ventricular ejection fraction to detect early signs of LV dysfunction. The study is a retrospective review of the medical records and transthoracic echocardiograms of rTOF patients who were seen in the pediatric cardiology clinic at our institution from August 2016 till May 2018. The rTOF group was compared with a matched healthy control group. Offline strain analysis of TTE studies was completed in each subject according to mode set by the American Society of Echocardiography. Twenty-two patients with rTOF and 22 age-matched controls (rTOF 18.7 ± 6 years and control 14.6 ± 9.6 years, P value 0.19) were included during the study period. The rTOF group consisted of 12 males and 10 females, whereas the control group consisted of 15 males and 7 females. There was no significant difference in terms of LV ejection fraction using both 2-chamber as well as 4-chamber views. Global LV longitudinal strain was significantly lower in the rTOF group compared with the control group (rTOF - 15.92 ± 3.16 vs control - 22.79 ± 2.45, P value 0.00). All 17 segments showed significantly lower longitudinal strains in rTOF group compared with the control group. Global circumferential left ventricle strain was significantly lower in the rTOF patients compared with the control group (- 17.24 ± 5.86 vs - 22.74 ± 3.99, P value 0.001). 13 out of 16 segments had lower circumferential strains in the rTOF patients compared with controls. Asymptomatic surgically repaired TOF patients exhibited abnormal segmental and global left ventricle longitudinal and circumferential strains despite having normal left ventricle ejection fraction. Our findings suggest subclinical damage to the left ventricle systolic function post-surgical repair of TOF. 2-D speckle-tracking echocardiography may be used as a valuable method in the early recognition of left myocardial systolic function impairment in patients after TOF repair. The application of this method to guide clinical decision and management of rTOF patients such as earlier pulmonary valve replacement or risk stratification for sudden cardiac death needs further investigation.

Long-term follow-up and sex differences in adults operated for tetralogy of Fallot

“…One study showed that asymptomatic paediatric TOF population with a normal LV EF already exhibited abnormal segmental and global LV longitudinal and circumferential strains compared with a matched healthy control group. 19 Interestingly, our study showed that male patients with TOF had worse RV function compared with female patients at long-term follow-up. This finding supports previous findings of Menting et al as they showed that male patients with TOF had significantly lower LV GLS and RV free wall strain compared with female patients and speculated that RV dysfunction adversely affects LV function, probably by mechanical coupling of the ventricles.…”

“…One study showed that asymptomatic paediatric TOF population with a normal LV EF already exhibited abnormal segmental and global LV longitudinal and circumferential strains compared with a matched healthy control group. 19 …”

Speckle tracking echocardiography before and after Surgical pulmonary valve replacement in Tetralogy of Fallot patients: Can STE elucidate early left ventricular dysfunction?

“…Such nding reveals the limitation of routine 2D echocardiography to assess and follow up of left ventricle function in these groups of patients. Speckle tracking echocardiography is more sensitive to the detection of left ventricle abnormalities than 2D echocardiography (3,15,(18)(19)(20)(21)(22)(23), and with regarding our nding it may be useful to unmask left ventricle dysfunction in the setting of repaired Tetralogy of Fallot follow up. Although to evaluate this hypothesis, we suppose more studies and prospective analysis of Speckle tracking echocardiography role in repaired Tetralogy of Fallot patients.…”

Biventricular strain and strain rate impairment shortly after surgical repair of tetralogy of Fallot in children: A case‐control study

“…In addition to changes in myocardial architecture, other factors including hypertrophy and hypoxic condition before corrective surgery, probable intraoperative myocardial damage, and pulmonary regurgitation following surgical repair contribute to postoperative ventricular dysfunction. It has been shown that transventricular incision for closing ventricular septal defect and relief of right ventricular outflow tract obstruction in TOF children increases the rate of late right ventricular dysfunction and worsens the long‐term clinical outcomes 1,14 . Furthermore, severe pulmonary regurgitation can put a volume overload on the right ventricle that may adversely affect the right ventricle systolic function.…”

“…Also, TOF children with double outlet right ventricle, atrioventricular septal defect or Secundum atrial septal defect, genetic syndromes, and postoperative complications were excluded from the study. The sample size was calculated based on the prior study by Mohammad Nijres et al 14 reporting means of global circumferential left ventricular strain in repaired TOF patients (−17.24) and control group (−22.74). Hence, the estimated sample size for each group was 18 based on a type I error of 5%, power of 90%, and a formula for comparing means between two groups.…”