Case 2:
A 72 years old man was referred for the management of permanent atrial fibrillation with uncontrolled ventricular rates and LV dysfunction. Echocardiography showed moderate mitral regurgitation with LV ejection fraction of 32%. Atrioventricular junction (AVJ) ablation with physiological pacing option was recommended. LBBP was attempted as previously described. PVCs of changing morphology were noted while placing the lead deep inside the septum. Rotation was stopped immediately after observing PVC (VES2) with narrow QRS duration and qR in lead V1 (Figure 2A). Non-selective to selective capture of LBB could be demonstrated at near threshold output (Figure 2D). LBB paced QRS mimicked VES2 with duration of 124ms and pLVAT of 65ms (Figure 2B). The pacing threshold was 0.6V/0.5ms and lead impedance of 730 ohms. LBB potential was recorded on the LBBP lead electrogram (LBB-ventricular interval of 25ms, Figure 2C). AVJ ablation was completed using an irrigated-tip ablation catheter.