Zoll Medical Corp., designers and manufacturers of propriety noninvasive devices used to provide treatment to cardiac arrest victims, will soon be moving its headquarters from 32 Second Ave. in Burlington to 269 and 271 Mill Road in Chelmsford, MA. With plans of moving in July of this year, Zoll will be taking up the entire three floors of 269 Mill Road, totaling 129,959 square feet. The remaining 30,041 square feet will be subleased from the second floor of 271 Mill Road.