Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: New single lead pacemaker with the tip in the right ventricle . No pneumothorax . Mild pulmonary edema has improved . Bibasal subsegmental atelectasis , slightly increased in the right lower lobe . Mild cardiomegaly . Left shoulder arthroplasty is partially imaged
    OUTPUT:
    
Single lead pacer in good position , no pneumothorax .