Case 3:
A 65-year-old woman with NICM, LBBB and LV dysfunction (ejection fraction 30%) was referred for CRT. LBBP was performed using C315His sheath and 3830 Selectsecuretm lead. While positioning the lead deep inside the septum, PVCs with changing morphology were noted. Rotation was stopped immediately on observing PVC (VES3) with narrow QRS duration and qR in lead V1 (Figure 3A). No potentials were noted during baseline LBBB rhythm. The pacing threshold was 0.3V at 0.5ms and pacing impedance of 580 ohms. The final LBB paced QRS morphology mimicked VES3 (Figure 3B) with duration of 124ms (pLVAT – 78ms). RBB delay was corrected by optimizing the AV interval and pacing output (Figure 3C).