Utility of a novel pacing guidewire in pre-implantation testing at different left ventricular sites in cardiac...

This study aimed to evaluate the utility of a novel pacing guidewire in pre-implantation testing of different left ventricular (LV) sites during cardiac resynchronization therapy (CRT) procedures.

Ten consecutive patients (8 male, mean age 65.8 ± 4.9) undergoing CRT procedures were studied. Pacing threshold and R-wave sensing measured by the guidewire and LV lead at different LV sites were compared.

Thirty sites (6 apical, 13 middle, and 11 basal; 15 lateral and 15 anterior) were tested. There was significant correlation between pacing threshold (r = 0.878, p < 0.0001), and R-wave sensing (r = 0.896, p < 0.0001) obtained by guidewire and those obtained by LV lead. Separating into lateral and anterior sites, significant correlation was also found in pacing threshold (lateral r = 0.658, p = 0.008; anterior r = 0.886, p < 0.0001) and R-wave sensing (lateral r = 0.887, p < 0.0001; anterior 0.865, p < 0.0001). For basal and middle sites, significant correlation was found in pacing threshold (basal r = 0.890, p < 0.0001; middle r = 0.878, p < 0.0001), and R-wave sensing (basal r = 0.930, p < 0.0001; middle r = 0.823, p < 0.001). No and borderline correlation was found in pacing threshold (r = 0.548, p = 0.26) and R-wave sensing (r = 0.835, p = 0.039), respectively, for apical sites. Concordance rate for the presence of phrenic nerve stimulation at high pacing output was 87%.

The accuracy of the novel pacing guidewire in pre-implantation testing in CRT procedures is site-dependent. There was good correlation with LV lead in the measurement of pacing threshold and R-wave sensing at basal and middle sites, but not apical sites. Presence of phrenic nerve stimulation can be predicted by guidewire testing with high accuracy.