Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . Patchy left base opacity is seen , possibly due to atelectasis vs artifact ; no focal consolidation seen on CT . Dual - lead left - sided pacemaker is again seen with leads extending to the expected positions of the right atrium and right ventricle . The right lung is clear . No large pleural effusion or pneumothorax is seen . Cardiac and mediastinal silhouettes are unremarkable . Aortic knob calcification is seen . There is no overt pulmonary edema .
    OUTPUT:
    
Patchy left base opacity is seen , possibly due to atelectasis vs artifact ; no focal consolidation seen on CT .