Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left - sided transvenous pacemaker is seen with leads in the standard position . Moderate cardiomegaly is stable . Increased opacity at the bilateral lung bases most likely represents an increase in bilateral small effusions and atelectasis ; however , can not exclude infection . There is no evidence of pulmonary vascular congestion . There is no pneumothorax .
    OUTPUT:
    
Increased opacity at the bilateral lung bases most likely due to small effusions and atelectasis ; however , can not exclude infection .