Background: Conduction system pacing is a novel pacing technique that aims to maintain physiological activation of the ventricles. It can be achieved by pacing the His-bundle or the left bundle branch area. Left bundle branch area pacing (LBBAP) has many advantages over His-bundle pacing including being technically easier and having more stable and lower thresholds. It may have the potential to become the predominant form of pacing for bradyarrhythmias and perhaps for cardiac resynchronization therapy. However, its use has only been studied in high-volume, tertiary centres and real-world experience in smaller hospitals is unknown. We present our real-world experience of LBBAP in a busy district general hospital.
Method: Patients underwent LBBAP if they had a bradycardia indication for pacing, but not if they met criteria for cardiac resynchronization therapy. Implant data and any acute complications were recorded. LBBAP capture was assessed according to previously defined criteria, briefly; during unipolar-tip pacing, there was evidence of right bundle branch morphology in lead V1, a constant V6 peak left ventricular activation time of <80 ms at 5 V and 1 V, or a transition from non-selective to selective left bundle branch capture at near-threshold outputs. The procedure was undertaken using 3830 Medtronic or Ingevity plus Boston leads.
Results: LBBAP was attempted in 14 patients: 75 ± 11 years, 79% male, left ventricular ejection fraction of 49 ± 6% and intrinsic QRS duration of 111 ± 22 ms. The indication for LBBAP was high-degree atrioventricular block in 71% of patients and sinus node disease in 29%. Thirteen cases resulted in successful LBBAP according to the pre-defined criteria, but in 1 case we were unable to achieve LBBAP capture, so a conventional endocardial right ventricular lead was implanted. The mean fluoroscopic time was 20 ± 9minutes and radiation dose of 84 ± 22 cGy/cm2. The paced QRS duration was 109 ± 16 ms, R wave sensing was 14 ± 6 Mv and pacing thresholds were ≤1 V at 0.4 ms in all cases. There was no significant difference in the paced and intrinsic QRS duration (P=0.944). The pacing parameters remained stable at the post-implant check and there were no major or minor acute complications.
Conclusion: Our initial experience with LBBAP shows it can be effectively carried out in a district general hospital without the need for a dedicated electrophysiological haemodynamic system. Further studies are needed to assess its overall safety and clinical utility for different pacing indications. ❑
Figure 1: A) ECG intrinsic rhythm- CHB, B) ECG in bipolar pacing, C) ECG in unipolar pacing, D) fluoro-image/septogram showing lead position in LAO 30
