During active fixation of permanent pacemaker leads, the appearance of current of injury (COI) on intracardiac electrogram signals has long been used as an indicator of adequate mechanical contact between the lead and the myocardium. Despite its clinical relevance, COI assessment in practice remains largely subjective and relies on visual interpretation by the operator, while quantitative parameters and their predictive value for long-term lead stability have not yet been standardized. The aim of this study was to conduct a prospective longitudinal study to analyse the dynamics of COI during implantation of the pacing lead for left bundle branch area pacing (LBBAP) and to evaluate the association between acute COI changes and long-term stability of pacing parameters. Ten patients with preserved left ventricular ejection fraction and no evidence of cardiomyopathy were included. Intracardiac electrograms were recorded at the time of lead fixation, and again at 5 and 10 minutes after fixation. Several quantitative parameters representing the intensity and time course of COI were used. The results demonstrated that COI parameters were changing significantly after lead fixation, reflecting acute electrophysiological adaptation at the lead–myocardium contact. A key finding was that the rate of COI decline was associated with the long-term pacing threshold: a slower reduction in COI correlated with lower and more stable pacing thresholds at three months, whereas faster disappearance of COI was associated with less favourable stability. These findings suggest that quantitative analysis of COI may complement clinical judgement during LBBAP implantation and serve as an early indicator of the quality of lead fixation. The results represent a step toward more objective evaluation and potential standardization of COI measurement, although larger studies will be required to validate these observations.
|
