Abstract: AIM: To investigate the changes of left ventricular( LV) size and function after transcatheter closure of patent ductus arteriosus( PDA) in patients with enlarged LV. METHODS: Patients aged≥12 years with isolated PDA and enlarged LV and undergoing successful transcatheter device closure between January 2004 and December 2012 were recruited and followed up by transthoracic echocardiogram.Patients with normal LV on the day following the procedure were followed-up for 6 months and those with enlarged LV were followed-up until the size was restored to normal. RESULTS: A total of 391 patients( 63 males) aged 12-75( 35 ± 16) years were included in the study. The diameter of the PDA at the pulmonary artery end was( 7 ± 2) mm. Both LV size and ejection fraction( LVEF) decreased 24 h after the procedure( P < 0. 05). Thirty-six( 9. 2%) patients were lost to follow-up. A normal-sized LV was observed in 140( 35. 8%) patients on the day following the procedure,including 108 patients( 30. 4%)at 1 month,38( 10. 7%) at 3 months,23( 6. 5%) at 6 months and 11( 3. 1%) at 12 months. An enlarged LV was still present in 35( 9. 9%) patients at 12 months after procedure. CONCLUSION: In patients with PDA and enlarged LV,device closure of PDA significantly decreases LV size and leads to marked deterioration of LV functions. Approximately 6 months are necessary for LVEF to restore to baseline level after PDA closure. Interruption of the left-to-right shunt does not indicate immediate normalization of size of the LV. In some patients,it takes 1 or more years for the LV to restore to normal size after this procedure.