Case series
A total of 22 patients underwent LBBP using the EIS catheter in National Heart Centre Singapore between May 2021 and October 2021. These included 21 pacemakers (4 patients with symptomatic sinus node dysfunction, 6 Tachy-Brady syndrome, 11 patients with high grade AV nodal conduction disease), and 1 cardiac resynchronization therapy devices. The mean age of patients were 71.7 years and 16 (72.7%) were males. Baseline patient characteristics are shown in Table 1.
A total of 19 (86%) LBBP was successfully performed out of 22 patients. There were 3 unsuccessful LBBP attempts:
  1. Patient 8 is a 75-year-old male with ischemic cardiomyopathy and left bundle branch block (LBBB) on baseline ECG. Attempts at LBBP in multiple positions did not result in a satisfactory narrowing of the QRS, suggesting that the conduction delay likely occurred distal to the septal LBB. An Abbott QuartetTMQuadripolar Traditional S-shape 86 cm coronary sinus lead was positioned in the lateral branch of the coronary sinus. Biventricular (BiV) pacing with SyncAV programmed on, resulted in a BiV paced QRS of 103 ms.
  2. Patient 15 is a 74-year-old female with symptomatic complete heart block (CHB). There was initial successful LBBP implantation with a non-selective LBBP QRS of 115 ms. Lead dislodgement occurred within 24 hours, necessitating lead revision and conversion to a conventional RV mid-septum pacing lead position.
  3. Patient 20 is a 79-year-old female with symptomatic tachy-brady syndrome. Repeated initial attempts at LBBP yielded unacceptably high pacing thresholds (the patient was on a Vaughan William Class 1C agent for rhythm control). The final position with acceptable pacing and sensing threshold likely captured only the left ventricular septum (paced QRS 130 ms, at both high and low outputs).