The right ventricular apex was the preferred site for ventricular activation for pacemakers for several decades.After the realization that apical pacing was associated with an increased risk of heart failure and atrial fibrillation his bundle pacing was rediscovered.Although two cases series of his bundle paced patients were published in the 1970 s it was not until over forty years later that his bundle pacing finally began to become established and it was claimed by some electrophysiologists that the era of physiological pacing had arrived.
Although his bundle pacing was considered to be physiologic,it was more technically daunting and typically required a higher ventricular capture voltage.There was also some frequency of delayed lead displacement and a shortened battery life paralleled the higher capture voltages.
In 2017 Huang et al described the next development in conduction system pacing-left bundle branch area pacing. In this technique the sheath is advanced about 1.5 centimeter from the site of his signal recording towards the apex and deeply inserted into the ventricular septum.It is less technically demanding than is his bundle pacing and requires a lower capture voltage and in some EP centers i has replaced His pacing as the go to conduction system pacing of choice.
In 2020 Ponnusamy et al (1)described a case in which they were unable to obtain a satisfactory left bundle branch area lead placement and then maneuvered the lead 2 cm lower and positioned the lead in the area of the left posterior fascicle. A similar case had been described by LJ Zen et al in 2019(2)
The 12 lead EKG with Left posterior fascicular pacing demonstrates a pattern of left anterior hemiblock.
1) Ponnusany, SS et al. Left posterior fascicular pacing. J Innov Cardiac Rhythm Manage 2021 12 (5) 4493
2)Zeng, l, et al Permanent left posterior fascicular area pacing through the interventricular septum in a patient with infra-Hisian block, Heart rhythm Reports, 2019, Aug 5 (8) 411-413