Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: single lead left - sided pacemaker present , with lead tip over right ventricle , not significantly changed . Right IJ Swan - Ganz catheter , tip overlying main pulmonary artery , a retracted compared with the prior study . Again seen is cardiomegaly , with sternotomy wires . There is upper zone redistribution and mild vascular plethora , minimally improved . There is atelectasis at both lung bases , slightly improved in retrocardiac region . Otherwise , no focal opacity . No gross effusion .
    OUTPUT:
    
Cardiomegaly , similar to prior . Repositioning of Swan - Ganz catheter , with tip now overlying main pulmonary artery . Retrocardiac opacity is slightly improved . Right cardiophrenic patchy opacity , question atelectasis , is unchanged . No new infiltrate identified . Upper zone redistribution and mild vascular plethora is minimally improved .