Left bundle branch pacing lead for sensing ventricular arrhythmias in implantable cardioverter-defibrillator: A pilot study (LBBP-ICD study)

Background Left bundle branch pacing(LBBP) has been suggested as an alternative modality for biventricular pacing in cardiac-resynchronization therapy(CRT) eligible patients. As it provides stable R-wave sensing, LBBP has been recently utilized to provide sensing of ventricular arrhythmia in patients receiving implantable cardioverter defibrillator(ICD) with CRT Objectives Aim of our study was to analyze the long-term safety and efficacy of LBBP lead for appropriate detection of ventricular arrhythmia and delivery of anti-tachycardia pacing(ATP) among patients requiring defibrillator therapy with CRT Methods CRT eligible patients who underwent successful LBBP-optimized ICD(LOT ICD) and LBBP-optimized CRT-D(LOT CRT-D) were enrolled. The LBBP lead was connected to RV-P/S port after capping the IS-1 connector-plug of the DF-1-ICD lead. LOT ICD or LOT CRT-D was decided based on correction of conduction system disease. Documented arrhythmia episodes and therapy delivered were analyzed. Results 30 patients were enrolled. Mean age 59.7±10.5 years. LBBP resulted in increase in LV ejection fraction(LVEF) from 29.9±4.6% to 43.9±11.2%(p <0.0001). During mean follow-up of 22.9±12.5 months, 254 ventricular arrhythmia events were documented. Appropriate(n=225;89%) events included NSVT(94%;n=212 episodes), VT(3.5%;n=8) and VF(1.5%;n=5). ATP efficacy in terminating VT was 75%. 11% of episodes(n=29) were inappropriately detected due to T-wave over-sensing(TWOS). Inappropriate therapy(ATP) was delivered for 14 episodes(5.5%). Three patients(10%) had worsening of tricuspid regurgitation. Conclusion Sensing from the LBBP lead for arrhythmia detection is safe as nearly 90% of the episodes were detected appropriately. Future studies with dedicated LBBP defibrillator lead along with algorithms to avoid oversensing can help in combining defibrillation with conduction system pacing.