Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were reviewed and compared to prior studies . Pacemaker leads from a left pectoral bielectrode pacer pass through the SVC and end in the upper atrium and the right ventricle respectively . Precise location is only possible with ultrasound correlation with the patient 's complex cardiac anatomy . Moderate cardiomegaly is unchanged . Small sternotomy wires suggest prior corrective surgery in childhood . Focal round opacity containing two linear radiodense lines and calcification over the left cardiac contour are likely from the patient 's prior mitral valve and patch leak repair respectively . Fragments of four implantable pacer leads project over the lower midline . Normal pleural and mediastinal surfaces .
    OUTPUT:
    
Pacemaker leads from a left pectoral bielectrode pacer pass through the SVC and end in the upper atrium and the right ventricle respectively .