WALTHAM, MA - On December 16th, Waltham 911 center received a call for a pedestrian struck on Stow Street, near Ravenswood Road, with a man in cardiac arrest. Engine 4, Squad 5, and Medics 1 and 2 were dispatched. Engine 4 signed off with a man unconscious, but breathing. He was transported to Lahey Hospital in serious condition.