Correlation of Left Ventricular Function by 3-Dimensional Echocardiography and Cardiac MRI in Post-Operative Tetralogy of Fallot Patient: A Prospective Study

Abstract

Background:  Left ventricular dysfunction is one of the risk factors for adverse outcomes in repaired TOF (rTOF). Due to unfavorable RV-LV interaction in rTOF, it is warranted that sophisticated diagnostic techniques are used to recognize the early LV dysfunction which may affect the outcome. Cardiac MRI (CMRI) is the preferred method for assessing LV volumes and ejection fraction, due to its superior spatial resolution and comprehensive volumetric data. Meanwhile, three-dimensional echocardiography is currently being explored as a promising new technique.

Aim: To assess the efficacy of three-dimensional echocardiography as a means of evaluating left ventricular (LV) function in patients who have undergone repair for Tetralogy of Fallot (TOF), and compare its performance with that of CMRI.

Materials and Methods: 37 patients (mean age ± standard deviation [SD], 20.46 ± 9.4 years) who had undergone TOF repair were included in the study. 3 patients had suboptimal echo window, so only 34 patients had 3 D echo, while 37 patients underwent cardiac MRI. Four or six full volumetric 3D volumetric data sets were acquired from apical 4C views using the 1.5–3.6 MHz 3D probe with GE Vivid 7 Ultrasound System (GE Healthcare, USA) at a frame rate of 20– 30 frames/s. CMR examinations were performed on 1.5T clinical MR Scanner (CMR Signa/GE CV/i. Left ventricular end-diastolic volume (LVEDV) and ejection fraction (EF) were calculated by both methods.

Results: The prevalence of LV dysfunction in rTOF was evaluated using both Cardiac MRI and 3D Echo. According to Cardiac MRI findings, 45.9% of patients exhibited mild dysfunction, 35.1% had moderate dysfunction, and 5.5% had severe dysfunction. Similarly, based on 3D Echo results, 50% of patients showed mild dysfunction, 29.4% had moderate dysfunction, and 5.9% had severe dysfunction. The majority of patients, as observed through both Cardiac MRI and 3D Echo assessments, displayed mild to moderate LV dysfunction. The mean LV End Systolic Volume on Cardiac MRI was 73.42 ± 29.61 while the mean LV End Systolic Volume on 3D Echo was 67.32 ± 25.11. There was no significant difference in mean LV End Systolic Volume in Cardiac MRI and 3D Echocardiography (p-value = 0.36).

Conclusion: 3D echocardiography serves as a promising tool for assessing LVEF and LV volume in postoperative TOF patients. Future studies on larger populations are warranted to further validate these results.