Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right atrial and ventricular pacemaker / defibrillator leads course in expected position . Changes of coronary artery bypass grafting are seen , with median sternotomy wires and mediastinal clips . Moderate cardiomegaly is unchanged , though central venous congestion and interstitial edema have slightly improved . There are persistent small bilateral pleural effusions and bibasilar pulmonary opacities .
    OUTPUT:
    
1 . Moderate congestive heart failure , improved from prior examination . 2 . Persistent bibasilar opacities may represent atelectasis , aspiration , and / or pneumonia .