Case 4:
A 73 years old woman with normal LV function presented with symptomatic complete heart block. LBBP was done using 3830 Selectsecuretm lead and C315His sheath. The pacing lead was positioned deep inside the septum by 4-5 rapid turns. PVCs with changing morphology were noted during lead advancement. Lead rotation was stopped immediately after observing narrow complex PVC (VES4) with qR pattern in lead V1 (figure 4A). Electrograms from the pacing lead demonstrated sharp left bundle potential (Figure 4C) preceding the ventricular electrogram (LB-ventricular interval of 20ms). Pacing threshold was 0.4V at 0.5ms and lead impedance was 680 ohms. The paced QRS morphology mimicked the narrow PVC morphology (VES4) with QRS duration of 114ms with pLVAT in lead V5 of 70ms (Figure 4B). RBB delay was corrected by optimizing pacing output to allow anodal capture (Figure 4D)