Clinical Use of an Implantable Standby Pacemaker

A completely implantable pacemaker that will not compete with naturally occurring conducted beats has been used in five patients. An external model of the same design was successfully used in an additional 12 patients. The implantable model, inserted transvenously, has a single cathode in the right ventricle and an anodal plate on the surface of the power pack. The cathode serves as the sensing probe as well as the driving electrode. Although, to our knowledge, this is the first description of such an implantable device, Lemberg previously described an external "demand" pacemaker.¹ The merits of transvenous pacing will not be discussed here. Reference can be made to the original work of Furman et al²for unipolar pacing and Parsonnet et al³for bipolar pacing. The use of an implantable pacemaker attached to a permanent transvenous electrode has been reported by the authors and by other investigators.⁴