The transvenous, or pervenous, procedure involved incision of a vein into which was inserted the catheter electrode lead under fluoroscopic guidance, until it was lodged within the trabeculae of the right ventricle.
This method was to become the method of choice by the mid-1960s.
In 1958 Colombian doctor Alberto Vejarano Laverde and Colombian electrical engineer Jorge Reynolds Pombo constructed an external pacemaker, similar to those of Hopps and Zoll, weighing 45 kg and powered by a 12 volt car lead acid battery, but connected to electrodes attached to the heart.
This apparatus was successfully used to sustain a 70-year-old priest, Gerardo Florez.
Lidwell may have been aware of this and did not proceed with his experiments in humans".