Improvement in cardiac structure and functions early after transcatheter closure of secundum atrial septal defect in children and adolescents - Murat Muhtar Yılmazer; Barış Güven; Özgül Vupa-Çilengiroğlu; Taliha Öner; Savaş Demirpençe; Timur Meşe; Vedide Tavlı (The Turkish Journal of Pediatrics)