Left ventricular (LV) dysfunction in patients with repaired tetralogy of Fallot (rTOF) is an important risk factor for adverse outcomes. The aim of this study was to assess the details and time course of such LV dysfunction using layer-specific strain analysis by echocardiography.Methods and Results:The 66 patients with rTOF (mean age, 16.3±9.3 years) were divided into 3 groups (T1: 4-10 years, T2: 11-20 years, T3: 21-43 years), and 113 controls of similar age (mean age, 17.2±9.3 years) were divided into 3 corresponding groups (C1, C2, and C3). Layer-specific longitudinal strain (LS) and circumferential strain (CS) of 3 myocardial layers (endocardial, midmyocardial, and epicardial) were determined by echocardiography. Basal and papillary endocardial CS values were decreased in T1 compared with C1. With the exception of papillary epicardial CS, basal/papillary CS and LS of all 3 layers decreased in T2 compared with C2. Excepting papillary epicardial CS, all other values were decreased in T3 compared with C3.