Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided ICD device is re - demonstrated with single lead terminating in the right ventricle . Moderate cardiomegaly is again noted . Mediastinal contours are similar . Previously demonstrated linear lucencies about the mediastinum are not visualized on the current exam , and no definite evidence for pneumomediastinum is present . There is mild upper zone vascular redistribution without overt pulmonary edema , overall improved . Patchy opacities in the lung bases likely reflect areas of atelectasis . No pneumothorax or pleural effusion is demonstrated . There are no acute osseous abnormalities .
    OUTPUT:
    
No definite findings suggestive of pneumomediastinum . Mild pulmonary vascular congestion , improved from the prior study , with bibasilar atelectasis .