 The new device launched a small company that grew to be known as the Zoll Medical Corporation.Paul Zoll developed methods of applying electric shocks to the surface of the chest that stimulated the heart within.When the heart of his first clinical success ceased to beat because its native stimulus signal failed, Zoll saved the man by substituting a sequence of chest shocks produced by an experimental pacemaker borrowed from Otto Krayer of the Harvard Medical School Department of Physiology.