Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . Lung volumes are low . Moderate cardiomegaly is chronic , but worsened engorgement and cephalization of lung vessels is consistent with acute cardiac decompsation . Lungs are clear . The aortic knob is calcified . No substantial pleural effusion or pneumothorax .
    OUTPUT:
    
Acute decompensation of chronically enlarged heart .