COMPARison of Lumenless versus Stylet-driven Lead Systems in Left Bundle Branch Pacing - COMPARE LBBP

Left bundle branch pacing (LBBP) is a rapidly emerging pacing modality. Traditionally, lumenless fixed helix lead is used for LBBP delivered with a fixed curve or preshaped deflectable delivery catheter. However, it can also be done with stylet driven lead when used with appropriate delivery catheter. In this clinical trial one arm will receive lumen less lead and another will receive stylet driven lead for LBBP. No investigational therapy is involved as both methods are tested and currently in use. Intervention arm will receive stylet driven lead system. LBBP will be performed with stylet driven lead delivered to target location through a delivery catheter. A pre-shaped delivery catheter (such as CPS Locator 3D sheth) will be used which is standard of care. Left bundle capture will be confirmed by paced RBBB morphology plus one of the following. 1. V6-R wave peak time <75 ms in patients with narrow QRS and <80 ms in patients with bundle branch block, 2. V6-V1 inter peak interval of >44 ms, 3. transition from nonselective to selective left bundle branch or left ventricular septal capture. 'Template beat' be used to guide the procedure if induced during lead implantation. Procedure will be performed once and confirmation of left bundle branch capture will be considered acute success. Usual procedural duration is ~1-2 hours. Procedure will be performed by experienced cardiac electrophysiologist specialised in left bundle branch pacing. Another cardiac electrophysiologist will be independently responsible for validating the left bundle branch capture and independent team of cardiac physiologists will be responsible for collecting data regarding procedure start, end and electrocardiographic parameters.