His bundle electrograms.

Since the recording of the first human electrocardiogram by Wailer in I889 the science of electrocardiography has developed and advanced rapidly, but has been limited by the inability to record electrical activity from specialized areas of the heart. A significant contribution was made by Alanis, Gonzailez, and L6pez in 1958 when they recorded His bundle potentials in the isolated perfused dog heart using fine needle electrodes placed along the atrioventricular groove. The first His potentials to be recorded in humans were described by Giraud, Puech, and Latour (i960), and later by Watson, EmslieSmith, and Lowe (I967). However, it was left to Scherlag and associates (I969) to develop a simple and safe electrode catheter technique for the consistent recording of electrical potentials from the His bundle site in man. This technique was later extended to the recording of atrioventricular nodal and right bundlebranch potentials (Damato et al., i969a) and has resulted in an extensive investigation of the specialized conduction tissue in normal and abnormal circumstances. As a result certain age-old concepts have now been proved correct or have had to be modified, and in particular the traditional criteria for interpretation of many dysrhythmias have been shown to be inadequate.