BackgroundEchocardiogram has limitations in effectively assessing right ventricular (RV) function in children post tetralogy of Fallot (TOF) repair. We evaluated the utility of speckle tracking echocardiography (STE)‐based RV global longitudinal strain (GLS) for the assessment of RV systolic function.MethodsAll patients with repaired TOF who had both echocardiograms and cardiac MRI (CMR) within a 6‐month interval were included. RV volumes and ejection fraction (EF) were obtained by CMRs. Traditional echocardiographic function parameters and RV GLS were compared to CMR‐derived RV EF. Subjects were divided into two groups based on CMR RV EF (group I: RV EF ≥45%; and group II: RV EF <45%).ResultsA total of 57 subjects were included. Mean age was 13.0±3.6 years and 58% were males. Group I had 39 subjects and group II had 18. Only six of the 18 patients (33%) in group II were identified as having at least mild RV dysfunction by echocardiogram. The mean RV GLS was significantly abnormal in group II (−15.3±3.8%) compared to group I (−20.9±3.3%; P<.001). By ROC analysis, an RV GLS cutoff value of −18% had 78% sensitivity and 77% specificity in identifying RV EF <45% (area under curve .87, P<.001). Intra‐ and inter‐observer reproducibility of RV GLS were good.ConclusionRV GLS is a simple and effective tool for the assessment of RV systolic function in patients post TOF repair. This technique would help further refine patient selection for timing of CMR and management.