Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are low in volume but clear . The cardiac silhouette is possibly mildly enlarged . Low lung volumes may be responsible for mild widening of the mediastinal silhouette . The hilar contours and pleural surfaces are normal . No pleural effusion is present . A left - sided pacer terminates with its leads in the right atrium and right ventricle . Non-standard placement of the right atrial lead is unchanged .
    OUTPUT:
    
Mild cardiomegaly . No acute intrathoracic process .