Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A pacemaker generator overlies the left anterior chest wall . The leads appear intact and project over the expected location of the right atrium and right ventricle . The lung volumes are low . Bibasilar opacities likely represent dependent atelectasis . No large pleural effusion is identified . There is mild pulmonary vascular congestion , though no overt edema . Mediastinal and hilar contours are within normal limits . Calcifications are noted within the aortic arch . The cardiac silhouette is severely enlarged .
    OUTPUT:
    
1 . Intact pacemaker leads in standard position . 2 . Low lung volumes with bibasilar atelectasis . 3 . Mild pulmonary vascular congestion , though no overt edema or large pleural effusions . 4 . Severe cardiomegaly .