Is this a case control study or retrospective cohort study?

From the echocardiography database at a tertiary care center, 1,625 subjects (mean age, 44 6 14 years; 47% men) with normal echocardiographic findings between 2000 and 2009 were identified. Gender dif- ferences and association with body surface area were assessed retrospectively for right atrial long-axis and short-axis dimensions, right ventricular short-axis dimension, end-diastolic and end-systolic right ventricular area, right ventricular fractional area change, and tricuspid annular plane systolic excursion. The impact of nor- mal values stratified for gender and body surface area was tested in 24 patients with moderate-sized to large atrial septal defects.